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  • Accidentally Changed Dual Monitor Setup and don't know how to reset it

    - by user203783
    I have a dual monitor setup with my laptop and an external Asus monitor running under Ubuntu 11.10. When I first started using Ubuntu, it synced both screens. What showed up on my laptop showed up on my eternal monitor. Last night, I accidentally knocked the HDMI cable from its port (not that unusual in the tight space I work in). When I plugged it back in, as usual, the external monitor only displayed my wallpaper. Usually, I just restart Ubuntu and it resets, but last night what I now realize was the display console came up and somehow I changed the setup. Now the two screens show different jobs so to speak. Also, the external monitor doesn't display the ribbon, making switching between Firefox tabs and windows or apps jarring. I write for a living and need to quickly check bits of research, notes or sources while writing and the extra switching between mouse pad and external mouse to get one or the other screen to respond interrupts my work flow. The only technical help I can offer is when the display console popped up, the graphical representation of the screens was that the external screen appeared layered over by about one-quarter of the laptop screen. Again, these were icons. I tried to replicate that after I obviously screwed things up. If someone could help. I would appreciate it. If I have to use terminal, that's fine. I started using computers for writing back when they were green DOS prompts. There's a certain elegance to prompt commands to me. Maybe it's the writer in me. Again, if anyone can help me return my screens to sync under Ubuntu 11.10, I would greatly appreciate it.

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  • Touchpad issues on HP Pavilion dm4 (can't right click)

    - by Habstinat
    Can anyone help me with my touchpad issues? I have a HP Pavilion dm4 and it has two areas on the bottom of the touchpad to designate right and left clicks. This mostly doesn't work on Ubuntu in the fact that it recognizes any taps on either tap zone as a left click. Instead, I have it set so if I tap anywhere on the pad it makes a left click. There should be, and there are, many ways in the mouse configuration window to simulate a right click using only a touchpad. None of these work. Changing mouse orientation doesn't do anything, "dwell click" also does nothing, and, the oddest part of this problem, whenever I try to turn "Simulated Secondary Click" off (it doesn't work anyways, but just to try to toggle it), the entire theme of my desktop changes to a gray Windows '95ey look. The only way to get rid of this is to close and reopen the mouse preferences window. My computer is fairly new and the Ubuntu installation is less than a day old. I didn't do anything that I think could cause this. The problem is that I can't right click. Help, please?s that I can't right click. Help, please? Afterword: I installed two scripts from http://sansmicrosoft.blogspot.com/2010/10/pavilion-dm4-1160-erratic-touchpad.html . They didn't do anything I couldn't already do, and they did not make it possible for me to right click. :(

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  • HDMI & Display Port stopped work on 11.10

    - by dizzy
    After upgraded two laptops to 11.10, HDMI and Display ports stopped to work. Symptoms on each (btw. it used to work with 11.04 on both): laptop Dell Inspiron 1525 (HDMI, Intel GMX 3100): after HDMI cable is plugged in, screen is corrupted (no panel, no icons), system is unresponsive, TV set receives some signal, but only blue screen and some regular ticks can be heard. Unplugging the cable system recovers. No logs were checked. Thinkpad W510 (DisplayPort, NVidia). Simple "Screens" utility does not recognizes TV set, but this is something to do with the differences between Nvidia driver API and the one expected from the utility, as far I could spot on the net. However, using Nvidia-settings, TV is recognized, but cannot be enabled and used. Beside that, touch pad freezes after HDMI2DisplayPort connector is plugged in the laptop (not immediately, but after few seconds - probably after some handshake with the TV set crashes). It is strange that no such bug reports can be found on the net. So, I guess it is something wrong on our laptops only, but would appreciate some hints (i.e. any known changes recently related to HDMI, Display Port, X-Windows, kernel... wherever I should take a look and fix the issue).

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  • If I had to create a server farm what should I do? (how others companies work?)

    - by Michel
    I have a business idea but this is not really my field so I'm trying to understand what I'm really dealing with. I have a general understanding of how a web farm works, I'm a web developer and I understand the technology behind it, but I'm curious to know specifically how a web farm is set up and which professionals are involved. Things to consider probably are the hardware, the power supply, the software managment, the cooling system and if possible the usage of green technology/power recycling. Basically, can you explain me how a web hosting company is structured and how it works? A big question, I know, but from what I already read here about the subject a lot of you know this stuff. Thanks for your time guys!

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  • HTG Reviews the CODE Keyboard: Old School Construction Meets Modern Amenities

    - by Jason Fitzpatrick
    There’s nothing quite as satisfying as the smooth and crisp action of a well built keyboard. If you’re tired of  mushy keys and cheap feeling keyboards, a well-constructed mechanical keyboard is a welcome respite from the $10 keyboard that came with your computer. Read on as we put the CODE mechanical keyboard through the paces. What is the CODE Keyboard? The CODE keyboard is a collaboration between manufacturer WASD Keyboards and Jeff Atwood of Coding Horror (the guy behind the Stack Exchange network and Discourse forum software). Atwood’s focus was incorporating the best of traditional mechanical keyboards and the best of modern keyboard usability improvements. In his own words: The world is awash in terrible, crappy, no name how-cheap-can-we-make-it keyboards. There are a few dozen better mechanical keyboard options out there. I’ve owned and used at least six different expensive mechanical keyboards, but I wasn’t satisfied with any of them, either: they didn’t have backlighting, were ugly, had terrible design, or were missing basic functions like media keys. That’s why I originally contacted Weyman Kwong of WASD Keyboards way back in early 2012. I told him that the state of keyboards was unacceptable to me as a geek, and I proposed a partnership wherein I was willing to work with him to do whatever it takes to produce a truly great mechanical keyboard. Even the ardent skeptic who questions whether Atwood has indeed created a truly great mechanical keyboard certainly can’t argue with the position he starts from: there are so many agonizingly crappy keyboards out there. Even worse, in our opinion, is that unless you’re a typist of a certain vintage there’s a good chance you’ve never actually typed on a really nice keyboard. Those that didn’t start using computers until the mid-to-late 1990s most likely have always typed on modern mushy-key keyboards and never known the joy of typing on a really responsive and crisp mechanical keyboard. Is our preference for and love of mechanical keyboards shining through here? Good. We’re not even going to try and hide it. So where does the CODE keyboard stack up in pantheon of keyboards? Read on as we walk you through the simple setup and our experience using the CODE. Setting Up the CODE Keyboard Although the setup of the CODE keyboard is essentially plug and play, there are two distinct setup steps that you likely haven’t had to perform on a previous keyboard. Both highlight the degree of care put into the keyboard and the amount of customization available. Inside the box you’ll find the keyboard, a micro USB cable, a USB-to-PS2 adapter, and a tool which you may be unfamiliar with: a key puller. We’ll return to the key puller in a moment. Unlike the majority of keyboards on the market, the cord isn’t permanently affixed to the keyboard. What does this mean for you? Aside from the obvious need to plug it in yourself, it makes it dead simple to repair your own keyboard cord if it gets attacked by a pet, mangled in a mechanism on your desk, or otherwise damaged. It also makes it easy to take advantage of the cable routing channels in on the underside of the keyboard to  route your cable exactly where you want it. While we’re staring at the underside of the keyboard, check out those beefy rubber feet. By peripherals standards they’re huge (and there is six instead of the usual four). Once you plunk the keyboard down where you want it, it might as well be glued down the rubber feet work so well. After you’ve secured the cable and adjusted it to your liking, there is one more task  before plug the keyboard into the computer. On the bottom left-hand side of the keyboard, you’ll find a small recess in the plastic with some dip switches inside: The dip switches are there to switch hardware functions for various operating systems, keyboard layouts, and to enable/disable function keys. By toggling the dip switches you can change the keyboard from QWERTY mode to Dvorak mode and Colemak mode, the two most popular alternative keyboard configurations. You can also use the switches to enable Mac-functionality (for Command/Option keys). One of our favorite little toggles is the SW3 dip switch: you can disable the Caps Lock key; goodbye accidentally pressing Caps when you mean to press Shift. You can review the entire dip switch configuration chart here. The quick-start for Windows users is simple: double check that all the switches are in the off position (as seen in the photo above) and then simply toggle SW6 on to enable the media and backlighting function keys (this turns the menu key on the keyboard into a function key as typically found on laptop keyboards). After adjusting the dip switches to your liking, plug the keyboard into an open USB port on your computer (or into your PS/2 port using the included adapter). Design, Layout, and Backlighting The CODE keyboard comes in two flavors, a traditional 87-key layout (no number pad) and a traditional 104-key layout (number pad on the right hand side). We identify the layout as traditional because, despite some modern trapping and sneaky shortcuts, the actual form factor of the keyboard from the shape of the keys to the spacing and position is as classic as it comes. You won’t have to learn a new keyboard layout and spend weeks conditioning yourself to a smaller than normal backspace key or a PgUp/PgDn pair in an unconventional location. Just because the keyboard is very conventional in layout, however, doesn’t mean you’ll be missing modern amenities like media-control keys. The following additional functions are hidden in the F11, F12, Pause button, and the 2×6 grid formed by the Insert and Delete rows: keyboard illumination brightness, keyboard illumination on/off, mute, and then the typical play/pause, forward/backward, stop, and volume +/- in Insert and Delete rows, respectively. While we weren’t sure what we’d think of the function-key system at first (especially after retiring a Microsoft Sidewinder keyboard with a huge and easily accessible volume knob on it), it took less than a day for us to adapt to using the Fn key, located next to the right Ctrl key, to adjust our media playback on the fly. Keyboard backlighting is a largely hit-or-miss undertaking but the CODE keyboard nails it. Not only does it have pleasant and easily adjustable through-the-keys lighting but the key switches the keys themselves are attached to are mounted to a steel plate with white paint. Enough of the light reflects off the interior cavity of the keys and then diffuses across the white plate to provide nice even illumination in between the keys. Highlighting the steel plate beneath the keys brings us to the actual construction of the keyboard. It’s rock solid. The 87-key model, the one we tested, is 2.0 pounds. The 104-key is nearly a half pound heavier at 2.42 pounds. Between the steel plate, the extra-thick PCB board beneath the steel plate, and the thick ABS plastic housing, the keyboard has very solid feel to it. Combine that heft with the previously mentioned thick rubber feet and you have a tank-like keyboard that won’t budge a millimeter during normal use. Examining The Keys This is the section of the review the hardcore typists and keyboard ninjas have been waiting for. We’ve looked at the layout of the keyboard, we’ve looked at the general construction of it, but what about the actual keys? There are a wide variety of keyboard construction techniques but the vast majority of modern keyboards use a rubber-dome construction. The key is floated in a plastic frame over a rubber membrane that has a little rubber dome for each key. The press of the physical key compresses the rubber dome downwards and a little bit of conductive material on the inside of the dome’s apex connects with the circuit board. Despite the near ubiquity of the design, many people dislike it. The principal complaint is that dome keyboards require a complete compression to register a keystroke; keyboard designers and enthusiasts refer to this as “bottoming out”. In other words, the register the “b” key, you need to completely press that key down. As such it slows you down and requires additional pressure and movement that, over the course of tens of thousands of keystrokes, adds up to a whole lot of wasted time and fatigue. The CODE keyboard features key switches manufactured by Cherry, a company that has manufactured key switches since the 1960s. Specifically the CODE features Cherry MX Clear switches. These switches feature the same classic design of the other Cherry switches (such as the MX Blue and Brown switch lineups) but they are significantly quieter (yes this is a mechanical keyboard, but no, your neighbors won’t think you’re firing off a machine gun) as they lack the audible click found in most Cherry switches. This isn’t to say that they keyboard doesn’t have a nice audible key press sound when the key is fully depressed, but that the key mechanism isn’t doesn’t create a loud click sound when triggered. One of the great features of the Cherry MX clear is a tactile “bump” that indicates the key has been compressed enough to register the stroke. For touch typists the very subtle tactile feedback is a great indicator that you can move on to the next stroke and provides a welcome speed boost. Even if you’re not trying to break any word-per-minute records, that little bump when pressing the key is satisfying. The Cherry key switches, in addition to providing a much more pleasant typing experience, are also significantly more durable than dome-style key switch. Rubber dome switch membrane keyboards are typically rated for 5-10 million contacts whereas the Cherry mechanical switches are rated for 50 million contacts. You’d have to write the next War and Peace  and follow that up with A Tale of Two Cities: Zombie Edition, and then turn around and transcribe them both into a dozen different languages to even begin putting a tiny dent in the lifecycle of this keyboard. So what do the switches look like under the classicly styled keys? You can take a look yourself with the included key puller. Slide the loop between the keys and then gently beneath the key you wish to remove: Wiggle the key puller gently back and forth while exerting a gentle upward pressure to pop the key off; You can repeat the process for every key, if you ever find yourself needing to extract piles of cat hair, Cheeto dust, or other foreign objects from your keyboard. There it is, the naked switch, the source of that wonderful crisp action with the tactile bump on each keystroke. The last feature worthy of a mention is the N-key rollover functionality of the keyboard. This is a feature you simply won’t find on non-mechanical keyboards and even gaming keyboards typically only have any sort of key roller on the high-frequency keys like WASD. So what is N-key rollover and why do you care? On a typical mass-produced rubber-dome keyboard you cannot simultaneously press more than two keys as the third one doesn’t register. PS/2 keyboards allow for unlimited rollover (in other words you can’t out type the keyboard as all of your keystrokes, no matter how fast, will register); if you use the CODE keyboard with the PS/2 adapter you gain this ability. If you don’t use the PS/2 adapter and use the native USB, you still get 6-key rollover (and the CTRL, ALT, and SHIFT don’t count towards the 6) so realistically you still won’t be able to out type the computer as even the more finger twisting keyboard combos and high speed typing will still fall well within the 6-key rollover. The rollover absolutely doesn’t matter if you’re a slow hunt-and-peck typist, but if you’ve read this far into a keyboard review there’s a good chance that you’re a serious typist and that kind of quality construction and high-number key rollover is a fantastic feature.  The Good, The Bad, and the Verdict We’ve put the CODE keyboard through the paces, we’ve played games with it, typed articles with it, left lengthy comments on Reddit, and otherwise used and abused it like we would any other keyboard. The Good: The construction is rock solid. In an emergency, we’re confident we could use the keyboard as a blunt weapon (and then resume using it later in the day with no ill effect on the keyboard). The Cherry switches are an absolute pleasure to type on; the Clear variety found in the CODE keyboard offer a really nice middle-ground between the gun-shot clack of a louder mechanical switch and the quietness of a lesser-quality dome keyboard without sacrificing quality. Touch typists will love the subtle tactile bump feedback. Dip switch system makes it very easy for users on different systems and with different keyboard layout needs to switch between operating system and keyboard layouts. If you’re investing a chunk of change in a keyboard it’s nice to know you can take it with you to a different operating system or “upgrade” it to a new layout if you decide to take up Dvorak-style typing. The backlighting is perfect. You can adjust it from a barely-visible glow to a blazing light-up-the-room brightness. Whatever your intesity preference, the white-coated steel backplate does a great job diffusing the light between the keys. You can easily remove the keys for cleaning (or to rearrange the letters to support a new keyboard layout). The weight of the unit combined with the extra thick rubber feet keep it planted exactly where you place it on the desk. The Bad: While you’re getting your money’s worth, the $150 price tag is a shock when compared to the $20-60 price tags you find on lower-end keyboards. People used to large dedicated media keys independent of the traditional key layout (such as the large buttons and volume controls found on many modern keyboards) might be off put by the Fn-key style media controls on the CODE. The Verdict: The keyboard is clearly and heavily influenced by the needs of serious typists. Whether you’re a programmer, transcriptionist, or just somebody that wants to leave the lengthiest article comments the Internet has ever seen, the CODE keyboard offers a rock solid typing experience. Yes, $150 isn’t pocket change, but the quality of the CODE keyboard is so high and the typing experience is so enjoyable, you’re easily getting ten times the value you’d get out of purchasing a lesser keyboard. Even compared to other mechanical keyboards on the market, like the Das Keyboard, you’re still getting more for your money as other mechanical keyboards don’t come with the lovely-to-type-on Cherry MX Clear switches, back lighting, and hardware-based operating system keyboard layout switching. If it’s in your budget to upgrade your keyboard (especially if you’ve been slogging along with a low-end rubber-dome keyboard) there’s no good reason to not pickup a CODE keyboard. Key animation courtesy of Geekhack.org user Lethal Squirrel.       

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  • A Taxonomy of Numerical Methods v1

    - by JoshReuben
    Numerical Analysis – When, What, (but not how) Once you understand the Math & know C++, Numerical Methods are basically blocks of iterative & conditional math code. I found the real trick was seeing the forest for the trees – knowing which method to use for which situation. Its pretty easy to get lost in the details – so I’ve tried to organize these methods in a way that I can quickly look this up. I’ve included links to detailed explanations and to C++ code examples. I’ve tried to classify Numerical methods in the following broad categories: Solving Systems of Linear Equations Solving Non-Linear Equations Iteratively Interpolation Curve Fitting Optimization Numerical Differentiation & Integration Solving ODEs Boundary Problems Solving EigenValue problems Enjoy – I did ! Solving Systems of Linear Equations Overview Solve sets of algebraic equations with x unknowns The set is commonly in matrix form Gauss-Jordan Elimination http://en.wikipedia.org/wiki/Gauss%E2%80%93Jordan_elimination C++: http://www.codekeep.net/snippets/623f1923-e03c-4636-8c92-c9dc7aa0d3c0.aspx Produces solution of the equations & the coefficient matrix Efficient, stable 2 steps: · Forward Elimination – matrix decomposition: reduce set to triangular form (0s below the diagonal) or row echelon form. If degenerate, then there is no solution · Backward Elimination –write the original matrix as the product of ints inverse matrix & its reduced row-echelon matrix à reduce set to row canonical form & use back-substitution to find the solution to the set Elementary ops for matrix decomposition: · Row multiplication · Row switching · Add multiples of rows to other rows Use pivoting to ensure rows are ordered for achieving triangular form LU Decomposition http://en.wikipedia.org/wiki/LU_decomposition C++: http://ganeshtiwaridotcomdotnp.blogspot.co.il/2009/12/c-c-code-lu-decomposition-for-solving.html Represent the matrix as a product of lower & upper triangular matrices A modified version of GJ Elimination Advantage – can easily apply forward & backward elimination to solve triangular matrices Techniques: · Doolittle Method – sets the L matrix diagonal to unity · Crout Method - sets the U matrix diagonal to unity Note: both the L & U matrices share the same unity diagonal & can be stored compactly in the same matrix Gauss-Seidel Iteration http://en.wikipedia.org/wiki/Gauss%E2%80%93Seidel_method C++: http://www.nr.com/forum/showthread.php?t=722 Transform the linear set of equations into a single equation & then use numerical integration (as integration formulas have Sums, it is implemented iteratively). an optimization of Gauss-Jacobi: 1.5 times faster, requires 0.25 iterations to achieve the same tolerance Solving Non-Linear Equations Iteratively find roots of polynomials – there may be 0, 1 or n solutions for an n order polynomial use iterative techniques Iterative methods · used when there are no known analytical techniques · Requires set functions to be continuous & differentiable · Requires an initial seed value – choice is critical to convergence à conduct multiple runs with different starting points & then select best result · Systematic - iterate until diminishing returns, tolerance or max iteration conditions are met · bracketing techniques will always yield convergent solutions, non-bracketing methods may fail to converge Incremental method if a nonlinear function has opposite signs at 2 ends of a small interval x1 & x2, then there is likely to be a solution in their interval – solutions are detected by evaluating a function over interval steps, for a change in sign, adjusting the step size dynamically. Limitations – can miss closely spaced solutions in large intervals, cannot detect degenerate (coinciding) solutions, limited to functions that cross the x-axis, gives false positives for singularities Fixed point method http://en.wikipedia.org/wiki/Fixed-point_iteration C++: http://books.google.co.il/books?id=weYj75E_t6MC&pg=PA79&lpg=PA79&dq=fixed+point+method++c%2B%2B&source=bl&ots=LQ-5P_taoC&sig=lENUUIYBK53tZtTwNfHLy5PEWDk&hl=en&sa=X&ei=wezDUPW1J5DptQaMsIHQCw&redir_esc=y#v=onepage&q=fixed%20point%20method%20%20c%2B%2B&f=false Algebraically rearrange a solution to isolate a variable then apply incremental method Bisection method http://en.wikipedia.org/wiki/Bisection_method C++: http://numericalcomputing.wordpress.com/category/algorithms/ Bracketed - Select an initial interval, keep bisecting it ad midpoint into sub-intervals and then apply incremental method on smaller & smaller intervals – zoom in Adv: unaffected by function gradient à reliable Disadv: slow convergence False Position Method http://en.wikipedia.org/wiki/False_position_method C++: http://www.dreamincode.net/forums/topic/126100-bisection-and-false-position-methods/ Bracketed - Select an initial interval , & use the relative value of function at interval end points to select next sub-intervals (estimate how far between the end points the solution might be & subdivide based on this) Newton-Raphson method http://en.wikipedia.org/wiki/Newton's_method C++: http://www-users.cselabs.umn.edu/classes/Summer-2012/csci1113/index.php?page=./newt3 Also known as Newton's method Convenient, efficient Not bracketed – only a single initial guess is required to start iteration – requires an analytical expression for the first derivative of the function as input. Evaluates the function & its derivative at each step. Can be extended to the Newton MutiRoot method for solving multiple roots Can be easily applied to an of n-coupled set of non-linear equations – conduct a Taylor Series expansion of a function, dropping terms of order n, rewrite as a Jacobian matrix of PDs & convert to simultaneous linear equations !!! Secant Method http://en.wikipedia.org/wiki/Secant_method C++: http://forum.vcoderz.com/showthread.php?p=205230 Unlike N-R, can estimate first derivative from an initial interval (does not require root to be bracketed) instead of inputting it Since derivative is approximated, may converge slower. Is fast in practice as it does not have to evaluate the derivative at each step. Similar implementation to False Positive method Birge-Vieta Method http://mat.iitm.ac.in/home/sryedida/public_html/caimna/transcendental/polynomial%20methods/bv%20method.html C++: http://books.google.co.il/books?id=cL1boM2uyQwC&pg=SA3-PA51&lpg=SA3-PA51&dq=Birge-Vieta+Method+c%2B%2B&source=bl&ots=QZmnDTK3rC&sig=BPNcHHbpR_DKVoZXrLi4nVXD-gg&hl=en&sa=X&ei=R-_DUK2iNIjzsgbE5ID4Dg&redir_esc=y#v=onepage&q=Birge-Vieta%20Method%20c%2B%2B&f=false combines Horner's method of polynomial evaluation (transforming into lesser degree polynomials that are more computationally efficient to process) with Newton-Raphson to provide a computational speed-up Interpolation Overview Construct new data points for as close as possible fit within range of a discrete set of known points (that were obtained via sampling, experimentation) Use Taylor Series Expansion of a function f(x) around a specific value for x Linear Interpolation http://en.wikipedia.org/wiki/Linear_interpolation C++: http://www.hamaluik.com/?p=289 Straight line between 2 points à concatenate interpolants between each pair of data points Bilinear Interpolation http://en.wikipedia.org/wiki/Bilinear_interpolation C++: http://supercomputingblog.com/graphics/coding-bilinear-interpolation/2/ Extension of the linear function for interpolating functions of 2 variables – perform linear interpolation first in 1 direction, then in another. Used in image processing – e.g. texture mapping filter. Uses 4 vertices to interpolate a value within a unit cell. Lagrange Interpolation http://en.wikipedia.org/wiki/Lagrange_polynomial C++: http://www.codecogs.com/code/maths/approximation/interpolation/lagrange.php For polynomials Requires recomputation for all terms for each distinct x value – can only be applied for small number of nodes Numerically unstable Barycentric Interpolation http://epubs.siam.org/doi/pdf/10.1137/S0036144502417715 C++: http://www.gamedev.net/topic/621445-barycentric-coordinates-c-code-check/ Rearrange the terms in the equation of the Legrange interpolation by defining weight functions that are independent of the interpolated value of x Newton Divided Difference Interpolation http://en.wikipedia.org/wiki/Newton_polynomial C++: http://jee-appy.blogspot.co.il/2011/12/newton-divided-difference-interpolation.html Hermite Divided Differences: Interpolation polynomial approximation for a given set of data points in the NR form - divided differences are used to approximately calculate the various differences. For a given set of 3 data points , fit a quadratic interpolant through the data Bracketed functions allow Newton divided differences to be calculated recursively Difference table Cubic Spline Interpolation http://en.wikipedia.org/wiki/Spline_interpolation C++: https://www.marcusbannerman.co.uk/index.php/home/latestarticles/42-articles/96-cubic-spline-class.html Spline is a piecewise polynomial Provides smoothness – for interpolations with significantly varying data Use weighted coefficients to bend the function to be smooth & its 1st & 2nd derivatives are continuous through the edge points in the interval Curve Fitting A generalization of interpolating whereby given data points may contain noise à the curve does not necessarily pass through all the points Least Squares Fit http://en.wikipedia.org/wiki/Least_squares C++: http://www.ccas.ru/mmes/educat/lab04k/02/least-squares.c Residual – difference between observed value & expected value Model function is often chosen as a linear combination of the specified functions Determines: A) The model instance in which the sum of squared residuals has the least value B) param values for which model best fits data Straight Line Fit Linear correlation between independent variable and dependent variable Linear Regression http://en.wikipedia.org/wiki/Linear_regression C++: http://www.oocities.org/david_swaim/cpp/linregc.htm Special case of statistically exact extrapolation Leverage least squares Given a basis function, the sum of the residuals is determined and the corresponding gradient equation is expressed as a set of normal linear equations in matrix form that can be solved (e.g. using LU Decomposition) Can be weighted - Drop the assumption that all errors have the same significance –-> confidence of accuracy is different for each data point. Fit the function closer to points with higher weights Polynomial Fit - use a polynomial basis function Moving Average http://en.wikipedia.org/wiki/Moving_average C++: http://www.codeproject.com/Articles/17860/A-Simple-Moving-Average-Algorithm Used for smoothing (cancel fluctuations to highlight longer-term trends & cycles), time series data analysis, signal processing filters Replace each data point with average of neighbors. Can be simple (SMA), weighted (WMA), exponential (EMA). Lags behind latest data points – extra weight can be given to more recent data points. Weights can decrease arithmetically or exponentially according to distance from point. Parameters: smoothing factor, period, weight basis Optimization Overview Given function with multiple variables, find Min (or max by minimizing –f(x)) Iterative approach Efficient, but not necessarily reliable Conditions: noisy data, constraints, non-linear models Detection via sign of first derivative - Derivative of saddle points will be 0 Local minima Bisection method Similar method for finding a root for a non-linear equation Start with an interval that contains a minimum Golden Search method http://en.wikipedia.org/wiki/Golden_section_search C++: http://www.codecogs.com/code/maths/optimization/golden.php Bisect intervals according to golden ratio 0.618.. Achieves reduction by evaluating a single function instead of 2 Newton-Raphson Method Brent method http://en.wikipedia.org/wiki/Brent's_method C++: http://people.sc.fsu.edu/~jburkardt/cpp_src/brent/brent.cpp Based on quadratic or parabolic interpolation – if the function is smooth & parabolic near to the minimum, then a parabola fitted through any 3 points should approximate the minima – fails when the 3 points are collinear , in which case the denominator is 0 Simplex Method http://en.wikipedia.org/wiki/Simplex_algorithm C++: http://www.codeguru.com/cpp/article.php/c17505/Simplex-Optimization-Algorithm-and-Implemetation-in-C-Programming.htm Find the global minima of any multi-variable function Direct search – no derivatives required At each step it maintains a non-degenerative simplex – a convex hull of n+1 vertices. Obtains the minimum for a function with n variables by evaluating the function at n-1 points, iteratively replacing the point of worst result with the point of best result, shrinking the multidimensional simplex around the best point. Point replacement involves expanding & contracting the simplex near the worst value point to determine a better replacement point Oscillation can be avoided by choosing the 2nd worst result Restart if it gets stuck Parameters: contraction & expansion factors Simulated Annealing http://en.wikipedia.org/wiki/Simulated_annealing C++: http://code.google.com/p/cppsimulatedannealing/ Analogy to heating & cooling metal to strengthen its structure Stochastic method – apply random permutation search for global minima - Avoid entrapment in local minima via hill climbing Heating schedule - Annealing schedule params: temperature, iterations at each temp, temperature delta Cooling schedule – can be linear, step-wise or exponential Differential Evolution http://en.wikipedia.org/wiki/Differential_evolution C++: http://www.amichel.com/de/doc/html/ More advanced stochastic methods analogous to biological processes: Genetic algorithms, evolution strategies Parallel direct search method against multiple discrete or continuous variables Initial population of variable vectors chosen randomly – if weighted difference vector of 2 vectors yields a lower objective function value then it replaces the comparison vector Many params: #parents, #variables, step size, crossover constant etc Convergence is slow – many more function evaluations than simulated annealing Numerical Differentiation Overview 2 approaches to finite difference methods: · A) approximate function via polynomial interpolation then differentiate · B) Taylor series approximation – additionally provides error estimate Finite Difference methods http://en.wikipedia.org/wiki/Finite_difference_method C++: http://www.wpi.edu/Pubs/ETD/Available/etd-051807-164436/unrestricted/EAMPADU.pdf Find differences between high order derivative values - Approximate differential equations by finite differences at evenly spaced data points Based on forward & backward Taylor series expansion of f(x) about x plus or minus multiples of delta h. Forward / backward difference - the sums of the series contains even derivatives and the difference of the series contains odd derivatives – coupled equations that can be solved. Provide an approximation of the derivative within a O(h^2) accuracy There is also central difference & extended central difference which has a O(h^4) accuracy Richardson Extrapolation http://en.wikipedia.org/wiki/Richardson_extrapolation C++: http://mathscoding.blogspot.co.il/2012/02/introduction-richardson-extrapolation.html A sequence acceleration method applied to finite differences Fast convergence, high accuracy O(h^4) Derivatives via Interpolation Cannot apply Finite Difference method to discrete data points at uneven intervals – so need to approximate the derivative of f(x) using the derivative of the interpolant via 3 point Lagrange Interpolation Note: the higher the order of the derivative, the lower the approximation precision Numerical Integration Estimate finite & infinite integrals of functions More accurate procedure than numerical differentiation Use when it is not possible to obtain an integral of a function analytically or when the function is not given, only the data points are Newton Cotes Methods http://en.wikipedia.org/wiki/Newton%E2%80%93Cotes_formulas C++: http://www.siafoo.net/snippet/324 For equally spaced data points Computationally easy – based on local interpolation of n rectangular strip areas that is piecewise fitted to a polynomial to get the sum total area Evaluate the integrand at n+1 evenly spaced points – approximate definite integral by Sum Weights are derived from Lagrange Basis polynomials Leverage Trapezoidal Rule for default 2nd formulas, Simpson 1/3 Rule for substituting 3 point formulas, Simpson 3/8 Rule for 4 point formulas. For 4 point formulas use Bodes Rule. Higher orders obtain more accurate results Trapezoidal Rule uses simple area, Simpsons Rule replaces the integrand f(x) with a quadratic polynomial p(x) that uses the same values as f(x) for its end points, but adds a midpoint Romberg Integration http://en.wikipedia.org/wiki/Romberg's_method C++: http://code.google.com/p/romberg-integration/downloads/detail?name=romberg.cpp&can=2&q= Combines trapezoidal rule with Richardson Extrapolation Evaluates the integrand at equally spaced points The integrand must have continuous derivatives Each R(n,m) extrapolation uses a higher order integrand polynomial replacement rule (zeroth starts with trapezoidal) à a lower triangular matrix set of equation coefficients where the bottom right term has the most accurate approximation. The process continues until the difference between 2 successive diagonal terms becomes sufficiently small. Gaussian Quadrature http://en.wikipedia.org/wiki/Gaussian_quadrature C++: http://www.alglib.net/integration/gaussianquadratures.php Data points are chosen to yield best possible accuracy – requires fewer evaluations Ability to handle singularities, functions that are difficult to evaluate The integrand can include a weighting function determined by a set of orthogonal polynomials. Points & weights are selected so that the integrand yields the exact integral if f(x) is a polynomial of degree <= 2n+1 Techniques (basically different weighting functions): · Gauss-Legendre Integration w(x)=1 · Gauss-Laguerre Integration w(x)=e^-x · Gauss-Hermite Integration w(x)=e^-x^2 · Gauss-Chebyshev Integration w(x)= 1 / Sqrt(1-x^2) Solving ODEs Use when high order differential equations cannot be solved analytically Evaluated under boundary conditions RK for systems – a high order differential equation can always be transformed into a coupled first order system of equations Euler method http://en.wikipedia.org/wiki/Euler_method C++: http://rosettacode.org/wiki/Euler_method First order Runge–Kutta method. Simple recursive method – given an initial value, calculate derivative deltas. Unstable & not very accurate (O(h) error) – not used in practice A first-order method - the local error (truncation error per step) is proportional to the square of the step size, and the global error (error at a given time) is proportional to the step size In evolving solution between data points xn & xn+1, only evaluates derivatives at beginning of interval xn à asymmetric at boundaries Higher order Runge Kutta http://en.wikipedia.org/wiki/Runge%E2%80%93Kutta_methods C++: http://www.dreamincode.net/code/snippet1441.htm 2nd & 4th order RK - Introduces parameterized midpoints for more symmetric solutions à accuracy at higher computational cost Adaptive RK – RK-Fehlberg – estimate the truncation at each integration step & automatically adjust the step size to keep error within prescribed limits. At each step 2 approximations are compared – if in disagreement to a specific accuracy, the step size is reduced Boundary Value Problems Where solution of differential equations are located at 2 different values of the independent variable x à more difficult, because cannot just start at point of initial value – there may not be enough starting conditions available at the end points to produce a unique solution An n-order equation will require n boundary conditions – need to determine the missing n-1 conditions which cause the given conditions at the other boundary to be satisfied Shooting Method http://en.wikipedia.org/wiki/Shooting_method C++: http://ganeshtiwaridotcomdotnp.blogspot.co.il/2009/12/c-c-code-shooting-method-for-solving.html Iteratively guess the missing values for one end & integrate, then inspect the discrepancy with the boundary values of the other end to adjust the estimate Given the starting boundary values u1 & u2 which contain the root u, solve u given the false position method (solving the differential equation as an initial value problem via 4th order RK), then use u to solve the differential equations. Finite Difference Method For linear & non-linear systems Higher order derivatives require more computational steps – some combinations for boundary conditions may not work though Improve the accuracy by increasing the number of mesh points Solving EigenValue Problems An eigenvalue can substitute a matrix when doing matrix multiplication à convert matrix multiplication into a polynomial EigenValue For a given set of equations in matrix form, determine what are the solution eigenvalue & eigenvectors Similar Matrices - have same eigenvalues. Use orthogonal similarity transforms to reduce a matrix to diagonal form from which eigenvalue(s) & eigenvectors can be computed iteratively Jacobi method http://en.wikipedia.org/wiki/Jacobi_method C++: http://people.sc.fsu.edu/~jburkardt/classes/acs2_2008/openmp/jacobi/jacobi.html Robust but Computationally intense – use for small matrices < 10x10 Power Iteration http://en.wikipedia.org/wiki/Power_iteration For any given real symmetric matrix, generate the largest single eigenvalue & its eigenvectors Simplest method – does not compute matrix decomposition à suitable for large, sparse matrices Inverse Iteration Variation of power iteration method – generates the smallest eigenvalue from the inverse matrix Rayleigh Method http://en.wikipedia.org/wiki/Rayleigh's_method_of_dimensional_analysis Variation of power iteration method Rayleigh Quotient Method Variation of inverse iteration method Matrix Tri-diagonalization Method Use householder algorithm to reduce an NxN symmetric matrix to a tridiagonal real symmetric matrix vua N-2 orthogonal transforms     Whats Next Outside of Numerical Methods there are lots of different types of algorithms that I’ve learned over the decades: Data Mining – (I covered this briefly in a previous post: http://geekswithblogs.net/JoshReuben/archive/2007/12/31/ssas-dm-algorithms.aspx ) Search & Sort Routing Problem Solving Logical Theorem Proving Planning Probabilistic Reasoning Machine Learning Solvers (eg MIP) Bioinformatics (Sequence Alignment, Protein Folding) Quant Finance (I read Wilmott’s books – interesting) Sooner or later, I’ll cover the above topics as well.

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  • Windows Azure Use Case: Infrastructure Limits

    - by BuckWoody
    This is one in a series of posts on when and where to use a distributed architecture design in your organization's computing needs. You can find the main post here: http://blogs.msdn.com/b/buckwoody/archive/2011/01/18/windows-azure-and-sql-azure-use-cases.aspx  Description: Physical hardware components take up room, use electricity, create heat and therefore need cooling, and require wiring and special storage units. all of these requirements cost money to rent at a data-center or to build out at a local facility. In some cases, this can be a catalyst for evaluating options to remove this infrastructure requirement entirely by moving to a distributed computing environment. Implementation: There are three main options for moving to a distributed computing environment. Infrastructure as a Service (IaaS) The first option is simply to virtualize the current hardware and move the VM’s to a provider. You can do this with Microsoft’s Hyper-V product or other software, build the systems and host them locally on fewer physical machines. This is a good option for canned-applications (where you have to type setup.exe) but not as useful for custom applications, as you still have to license and patch those servers, and there are hard limits on the VM sizes. Software as a Service (SaaS) If there is already software available that does what you need, it may make sense to simply purchase not only the software license but the use of it on the vendor’s servers. Microsoft’s Exchange Online is an example of simply using an offering from a vendor on their servers. If you do not need a great deal of customization, have no interest in owning or extending the source code, and need to implement a solution quickly, this is a good choice. Platform as a Service (PaaS) If you do need to write software for your environment, your next choice is a Platform as a Service such as Windows Azure. In this case you no longer manager physical or even virtual servers. You start at the code and data level of control and responsibility, and your focus is more on the design and maintenance of the application itself. In this case you own the source code and can extend or change it as you see fit. An interesting side-benefit to using Windows Azure as a PaaS is that the Application Fabric component allows a hybrid approach, which gives you a basis to allow on-premise applications to leverage distributed computing paradigms. No one solution fits every situation. It’s common to see organizations pick a mixture of on-premise, IaaS, SaaS and PaaS components. In fact, that’s a great advantage to this form of computing - choice. References: 5 Enterprise steps for adopting a Platform as a Service: http://blogs.msdn.com/b/davidmcg/archive/2010/12/02/5-enterprise-steps-for-adopting-a-platform-as-a-service.aspx?wa=wsignin1.0  Application Patterns for the Cloud: http://blogs.msdn.com/b/kashif/archive/2010/08/07/application-patterns-for-the-cloud.aspx

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  • CodePlex Daily Summary for Saturday, June 18, 2011

    CodePlex Daily Summary for Saturday, June 18, 2011Popular ReleasesEffectControls-Silverlight controls with animation effects: EffectControls: EffectControlsMedia Companion: MC 3.408b weekly: Some minor fixes..... Fixed messagebox coming up during batch scrape Added <originaltitle></originaltitle> to movie nfo's - when a new movie is scraped, the original title will be set as the returned title. The end user can of course change the title in MC, however the original title will not change. The original title can be seen by hovering over the movie title in the right pane of the main movie tab. To update all of your current nfo's to add the original title the same as your current ...NLog - Advanced .NET Logging: NLog 2.0 Release Candidate: Release notes for NLog 2.0 RC can be found at http://nlog-project.org/nlog-2-rc-release-notesPowerGUI Visual Studio Extension: PowerGUI VSX 1.3.5: Changes - VS SDK no longer required to be installed (a bug in v. 1.3.4).Gendering Add-In for Microsoft Office Word 2010: Gendering Add-In: This is the first stable Version of the Gendering Add-In. Unzip the package and start "setup.exe". The .reg file shows how to config an alternate path for suggestion table.TerrariViewer: TerrariViewer v3.1 [Terraria Inventory Editor]: This version adds tool tips. Almost every picture box you mouse over will tell you what item is in that box. I have also cleaned up the GUI a little more to make things easier on my end. There are various bug fixes including ones associated with opening different characters in the same instance of the program. As always, please bring any bugs you find to my attention.CommonLibrary.NET: CommonLibrary.NET - 0.9.7 Beta: A collection of very reusable code and components in C# 3.5 ranging from ActiveRecord, Csv, Command Line Parsing, Configuration, Holiday Calendars, Logging, Authentication, and much more. Samples in <root>\src\Lib\CommonLibrary.NET\Samples CommonLibrary.NET 0.9.7Documentation 6738 6503 New 6535 Enhancements 6583 6737DropBox Linker: DropBox Linker 1.2: Public sub-folders are now monitored for changes as well (thanks to mcm69) Automatic public sync folder detection (thanks to mcm69) Non-Latin and special characters encoded correctly in URLs Pop-ups are now slot-based (use first free slot and will never be overlapped — test it while previewing timeout) Public sync folder setting is hidden when auto-detected Timeout interval is displayed in popup previews A lot of major and minor code refactoring performed .NET Framework 4.0 Client...Terraria World Viewer: Version 1.3: Update June 15th Removed "Draw Markers" checkbox from main window because of redundancy/confusing. (Select all or no items from the Settings tab for the same effect.) Fixed Marker preferences not being saved. It is now possible to render more than one map without having to restart the application. World file will not be locked while the world is being rendered. Note: The World Viewer might render an inaccurate map or even crash if Terraria decides to modify the World file during the pro...MVC Controls Toolkit: Mvc Controls Toolkit 1.1.5 RC: Added Extended Dropdown allows a prompt item to be inserted as first element. RequiredAttribute, if present, trggers if no element is chosen Client side javascript function to set/get the values of DateTimeInput, TypedTextBox, TypedEditDisplay, and to bind/unbind a "change" handler The selected page in the pager is applied the attribute selected-page="selected" that can be used in the definition of CSS rules to style the selected page items controls now interpret a null value as an empr...Umbraco CMS: Umbraco CMS 5.0 CTP 1: Umbraco 5 Community Technology Preview Umbraco 5 will be the next version of everyone's favourite, friendly ASP.NET CMS that already powers over 100,000 websites worldwide. Try out our first CTP of version 5 today! If you're new to Umbraco and would like to get a quick low-down on our popular and easy-to-learn approach to content management, check out our intro video here. What's in the v5 CTP box? This is a preview version of version 5 and includes support for the following familiar Umbr...Coding4Fun Kinect Toolkit: Coding4Fun.Kinect Toolkit: Version 1.0Kinect Mouse Cursor: Kinect Mouse Cursor v1.0: The initial release of the Kinect Mouse Cursor project!patterns & practices: Project Silk: Project Silk Community Drop 11 - June 14, 2011: Changes from previous drop: Many code changes: please see the readme.mht for details. New "Client Data Management and Caching" chapter. Updated "Application Notifications" chapter. Updated "Architecture" chapter. Updated "jQuery UI Widget" chapter. Updated "Widget QuickStart" appendix and code. Guidance Chapters Ready for Review The Word documents for the chapters are included with the source code in addition to the CHM to help you provide feedback. The PDF is provided as a separat...Orchard Project: Orchard 1.2: Build: 1.2.41 Published: 6/14/2010 How to Install Orchard To install Orchard using Web PI, follow these instructions: http://www.orchardproject.net/docs/Installing-Orchard.ashx. Web PI will detect your hardware environment and install the application. Alternatively, to install the release manually, download the Orchard.Web.1.2.41.zip file. http://orchardproject.net/docs/Manually-installing-Orchard-zip-file.ashx The zip contents are pre-built and ready-to-run. Simply extract the contents o...Snippet Designer: Snippet Designer 1.4.0: Snippet Designer 1.4.0 for Visual Studio 2010 Change logSnippet Explorer ChangesReworked language filter UI to work better in the side bar. Added result count drop down which lets you choose how many results to see. Language filter and result count choices are persisted after Visual Studio is closed. Added file name to search criteria. Search is now case insensitive. Snippet Editor Changes Snippet Editor ChangesAdded menu option for the $end$ symbol which indicates where the c...Mobile Device Detection and Redirection: 1.0.4.1: Stable Release 51 Degrees.mobi Foundation is the best way to detect and redirect mobile devices and their capabilities on ASP.NET and is being used on thousands of websites worldwide. We’re highly confident in our software and we recommend all users update to this version. Changes to Version 1.0.4.1Changed the BlackberryHandler and BlackberryVersion6Handler to have equal CONFIDENCE values to ensure they both get a chance at detecting BlackBerry version 4&5 and version 6 devices. Prior to thi...Rawr: Rawr 4.1.06: This is the Downloadable WPF version of Rawr!For web-based version see http://elitistjerks.com/rawr.php You can find the version notes at: http://rawr.codeplex.com/wikipage?title=VersionNotes Rawr AddonWe now have a Rawr Official Addon for in-game exporting and importing of character data hosted on Curse. The Addon does not perform calculations like Rawr, it simply shows your exported Rawr data in wow tooltips and lets you export your character to Rawr (including bag and bank items) like Char...AcDown????? - Anime&Comic Downloader: AcDown????? v3.0 Beta6: ??AcDown?????????????,?????????????,????、????。?????Acfun????? ????32??64? Windows XP/Vista/7 ????????????? ??:????????Windows XP???,?????????.NET Framework 2.0???(x86)?.NET Framework 2.0???(x64),?????"?????????"??? ??v3.0 Beta6 ?????(imanhua.com)????? ???? ?? ??"????","?????","?????","????"?????? "????"?????"????????"?? ??????????? ?????????????? ?????????????/???? ?? ????Windows 7???????????? ????????? ?? ????????????? ???????/??????????? ???????????? ?? ?? ?????(imanh...Pulse: Pulse Beta 2: - Added new wallpapers provider http://wallbase.cc. Supports english search, multiple keywords* - Improved font rendering in Options window - Added "Set wallpaper as logon background" option* - Fixed crashes if there is no internet connection - Fixed: Rewalls downloads empty images sometimes - Added filters* Note 1: wallbase provider supports only english search. Rewalls provider supports only russian search but Pulse automatically translates your english keyword into russian using Google Tr...New Projects.NET Entities Framework Utils: Project for creating supporting code to work with .NET Entity Framework.A Simple Demo of Industrial Process Monitoring System based on .NET & Arduino: The demo show some key points of .NET 1 .NET WPF 2 WCF 3 Sinverlight 4 ADO.Net The demo is a good sample for learing .NET and developing process monitoring system. The demo get temperture from Arduinot It is also a good Arduin sample.AHtml Pad: AHtml Pad is a powerfull html and css editor. It's made for beginnners and experimented programmers. It's made in vb.net with visual studio 2010Allena la mente: Raccolta di minigames per migliorare Memoria, Riflessi, Logica e Matematica. Applicazione in silverlight per Windows Phone. Carousel TeamAnorexia World: Ich habe ein kleines Project geschrieben dass mit einen MDI Formular eine komplette Office Suite (noch in hartz4) in einen verheint!AutomaSolution - IT Automation made easy!: AutomaSolution is a console application written in C#. It takes a single .xml file as input, and processes each section to perform an automation task. AzureManagmentAPI.NET: .NET Wrapper for Microsoft Windows Azure Service Managment REST API. It's developed in C# and uses .NET 4.0 Framework. More Information about the Windows Azure Service Management REST API can be found here: http://msdn.microsoft.com/en-us/library/ee460799.aspxCirrus: Projet en C# qui sert au recueillement de données multi-sites.Cruise Control .NET TV: Cruise Control .NET TV puts your project's integration status on a TV and adds coverage graphs generated through NCover.DBML Updater: External tool for Visual Studio which automatically updating DBML files, according to configuration files (XML). You can also specify rules for editing and deleting elements in DBML file. And supports source code generation on the end.EPiServer CMS Page Type Extensions: EPiServer PageTypeExtensions provide additional features related to page types in EPiServer CMS 6. They allow the developer to set restrictions on the number of pages that can be created under a page and also provide page type image preview functionality.Excel add-in library: Create Excel xll add-ins.Gendering Add-In for Microsoft Office Word 2010: Word Add-In that assists user by giving hints to write gender-neutral documents. The current function is a post-processing function to verify a written text against the rules of gender-neutral definition in German Language. The definitions are implemented in form of words and phrases and their gender-neutral replacement as a suggestion. The documentation is written in German. Word Add-In, das eine Unterstützung bietet, einen bereits geschriebenen Text zu überprüfen, nach einem definierten ...Kinductor: Kinductor puts you on the podium and in control of a full symphonic orchestra using just your hands and Kinect.LPFM Last.fm Scrobbler: LPFM Last.fm Scrobbler is a simple .NET API library for scrobbling to the Last.fm web service. It is designed for desktop, web and mobile applications that target the .NET 4 Framework. The library supports the Scrobble and Now Playing functionality of the Last.fm API version 2.0MDB RIA Service Generator: Auto-generates RIA service from a given mdb to create a lightswitch extension.mediaplayer-isen: super projet qui envoie du fat !!! ^^Metodología General Ajustada - MGA: Herramienta tecnológica que apoya la Metodología para la formulación y evaluación de Proyectos de Inversión Pública mejorada en Colombia. Metodología General Ajustada - MGA. Desarrollado en Visual C# 2008 y Base de datos SQL Server 2008.M-i-c-r-o-S-o-f-t-W-M-S: M8i8c8r8o8S8o8f8t M8i8c8r8o8S8o8f8t M8i8c8r8o8S8o8f8tmim: TBAMinecraft data viewing tools: A little toolset for Minecraft server. Contains a basic NBT reader and ingame map viewer.PHPCSERP: PHPCS ERP ????????????????????,???????????PDF???。 ???????????,??,??。 PHPCS ERP ??????????????????。 PHPCS ERP ?????????????,??????????????????????IT?????????????。 ??????????????? PHPCS ERP。 ??????IT?????????,??????????。Rangers Build Customization Guide: Scenario based and hands-on guidance for the customization and deployment of TFS Builds activities such as versioning, code signing, branching. Rangers Lab Management Guide: Practical and scenario-based guidance, backed by custom VM Template automation for reference environments Snail-Blog: ??asp.net?????SSIS Extensions - SFTP Task, PGP Task, Zip Task: A set of custom tasks to extend SSIS. Includes a SFTP task, PGP encryption task and zip/unzip task.stage: asp.net opensource testprojectTimeBook: Project Description A simple asp.net mvc project to manage time. The main reason for the project is to learn asp.net mvc. The end product will have the following features. Multiple companies/individuals can sign up. Each company/individual can add/remove/update their clients. UMDH Tracer: Tool that generates & exploits UMDH Dump so that leaks detection is easier.

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  • Chargeback and showback...both a 'throw back'

    - by llaszews
    Been getting asked again by customers and partners about chargeback and showback in the cloud so thought I would blog on my response to this question. Charge Back background, information and industry analysis: Cloud computing is all about shared resources. These shared resources are computer servers (including memory and CPU), network devices, hard disk storage, database servers, application servers, cooling, floor space, electricity and more. These resources are shared by departments within a company, or by a number of companies, when resources are hosted in the public or hybrid cloud. Currently, hosting providers that run other companies on their cloud platforms do not have an accurate way to measure the shared computing resources used by a specific user let alone used by a specific customer. Additionally, companies running their own cloud data centers, for private or hybrid clouds, have no way of measure and charging back the departments in the company that are using these shared cloud resources. In both cases, the lack of determine shared resource costs and to charge them back to the company, department or user that is using this resources is limited a clear measure of business benefit and impacting company’s ability to measure the Return on Investment (ROI). An IT chargeback system is an accounting strategy that applies the costs of IT services, hardware or software to the business unit in which they are used. This system contrasts with traditional IT accounting models in which a centralized department bears all of the IT costs in an organization and those costs are treated simply as corporate overhead. Showback involves showing the IT costs to a department or customer but not actually charging them for their IT usage. Showback is a gradual method of introducing chargeback into an enterprise. Most companies implement a show back mechanism before a full chargeback system is put in place. Oracle chargeback product: Oracle Enterprise Manager provides tools for defining detailed Chargeback plans spanning different metrics collected for each type of resources as well as defining Cost Centers for grouping costs across multiple developers. Chargeback plans can use not only usage based costs, but also configuration based costs (e.g. version of the platform) or fixed costs (e.g. flat-rate management fee). Chargeback has rich out of the box reports. Trending reports show how charge and resource consumption varies over time, while Summary reports show the breakdown of charges or usage by different dimensions such as Cost Center or Target Type. These reports help consumers in understanding how their charges relate to their consumption and also assist the IT department with budgeting and planning activities. With BI Publisher, the reports can be made available in a variety of formats such as PDF, HTML, Word, Excel or PowerPoint.

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  • Trying to configure HWIC-3G-HSPA

    - by user1174838
    I'm trying to configure a couple of Cisco 1941 routes. The are both identical routers. Each as a HWIC-1T (Smart Serial interface) and a HWIC-3G-HSPA 3G interface. These routers are to be sent to remote sites. We have connectivity to one of the sites but if remote site A gors down we lose connectivity to remote site B. The HWIC-1T is the primary WAN interface using frame relay joining the two remote sites We want the HWIC-3G-HSPA to be usable for direct connectivity from head office to remote site B, and also the HWIC-3G-HSPA is do be used for comms between the remote sites when the frame relay is down (happens quite a bit). I initialy tried to do dynamic routing using EIGRP however in my lab setup of laptop - 1941 - 1941 - laptop, I was unable to get end to end connectivity. I later settled on static routing and have got end to end connectivity but only over frame relay, not the HWIC-3G-HSPA. The sanitized running config for remote site A: version 15.1 service tcp-keepalives-in service tcp-keepalives-out service timestamps debug datetime msec service timestamps log datetime msec service password-encryption service udp-small-servers service tcp-small-servers ! hostname remoteA ! boot-start-marker boot-end-marker ! ! logging buffered 51200 warnings enable secret 5 censored ! no aaa new-model clock timezone wst 8 0 ! no ipv6 cef ip source-route ip cef ! ip domain name yourdomain.com multilink bundle-name authenticated ! chat-script gsm "" "ATDT*98*1#" TIMEOUT 30 "CONNECT" ! username admin privilege 15 secret 5 censored ! controller Cellular 0/1 ! interface Embedded-Service-Engine0/0 no ip address shutdown ! interface GigabitEthernet0/0 ip address 192.168.2.5 255.255.255.0 duplex auto speed auto ! interface GigabitEthernet0/1 no ip address shutdown duplex auto speed auto ! interface Serial0/0/0 ip address 10.1.1.2 255.255.255.252 encapsulation frame-relay cdp enable frame-relay interface-dlci 16 frame-relay lmi-type ansi ! interface Cellular0/1/0 ip address negotiated encapsulation ppp dialer in-band dialer idle-timeout 2147483 dialer string gsm dialer-group 1 async mode interactive ppp chap hostname censored ppp chap password 7 censored cdp enable ! interface Cellular0/1/1 no ip address encapsulation ppp ! interface Dialer0 no ip address ! ip forward-protocol nd ! no ip http server no ip http secure-server ! ip route 0.0.0.0 0.0.0.0 Serial0/0/0 210 permanent ip route 0.0.0.0 0.0.0.0 Cellular0/1/0 220 permanent ip route 172.31.2.0 255.255.255.0 Cellular0/1/0 permanent ip route 192.168.3.0 255.255.255.0 10.1.1.1 permanent ip route 192.168.3.0 255.255.255.0 Cellular0/1/0 210 permanent ! access-list 1 permit any dialer-list 1 protocol ip list 1 ! control-plane ! line con 0 logging synchronous login local line aux 0 line 2 no activation-character no exec transport preferred none transport input all transport output pad telnet rlogin lapb-ta mop udptn v120 ssh stopbits 1 line 0/1/0 exec-timeout 0 0 script dialer gsm login modem InOut no exec transport input all rxspeed 7200000 txspeed 5760000 line 0/1/1 no exec rxspeed 7200000 txspeed 5760000 line vty 0 4 access-class 23 in privilege level 15 password 7 censored login local transport input all line vty 5 15 access-class 23 in privilege level 15 password 7 censored login local transport input all line vty 16 1370 password 7 censored login transport input all ! scheduler allocate 20000 1000 end The sanitized running config for remote site B: version 15.1 service tcp-keepalives-in service tcp-keepalives-out service timestamps debug datetime msec service timestamps log datetime msec service password-encryption service udp-small-servers service tcp-small-servers ! hostname remoteB ! boot-start-marker boot-end-marker ! logging buffered 51200 warnings enable secret 5 censored ! no aaa new-model clock timezone wst 8 0 ! no ipv6 cef ip source-route ip cef ! no ip domain lookup ip domain name yourdomain.com multilink bundle-name authenticated ! chat-script gsm "" "ATDT*98*1#" TIMEOUT 30 "CONNECT" username admin privilege 15 secret 5 censored ! controller Cellular 0/1 ! interface Embedded-Service-Engine0/0 no ip address shutdown ! interface GigabitEthernet0/0 ip address 192.168.3.1 255.255.255.0 duplex auto speed auto ! interface GigabitEthernet0/1 no ip address shutdown duplex auto speed auto ! interface Serial0/0/0 ip address 10.1.1.1 255.255.255.252 encapsulation frame-relay clock rate 2000000 cdp enable frame-relay interface-dlci 16 frame-relay lmi-type ansi frame-relay intf-type dce ! interface Cellular0/1/0 ip address negotiated encapsulation ppp dialer in-band dialer idle-timeout 2147483 dialer string gsm dialer-group 1 async mode interactive ppp chap hostname censored ppp chap password 7 censored ppp ipcp dns request cdp enable ! interface Cellular0/1/1 no ip address encapsulation ppp ! interface Dialer0 no ip address ! ip forward-protocol nd ! no ip http server no ip http secure-server ! ip route 0.0.0.0 0.0.0.0 Serial0/0/0 210 permanent ip route 0.0.0.0 0.0.0.0 Cellular0/1/0 220 permanent ip route 172.31.2.0 255.255.255.0 Cellular0/1/0 permanent ip route 192.168.2.0 255.255.255.0 10.1.1.2 permanent ip route 192.168.2.0 255.255.255.0 Cellular0/1/0 210 permanent ! kron occurrence PING in 1 recurring policy-list ICMP ! access-list 1 permit any dialer-list 1 protocol ip list 1 ! control-plane ! line con 0 logging synchronous login local line aux 0 line 2 no activation-character no exec transport preferred none transport input all transport output pad telnet rlogin lapb-ta mop udptn v120 ssh stopbits 1 line 0/1/0 exec-timeout 0 0 script dialer gsm login modem InOut no exec transport input all rxspeed 7200000 txspeed 5760000 line 0/1/1 no exec rxspeed 7200000 txspeed 5760000 line vty 0 4 access-class 23 in privilege level 15 password 7 censored login transport input all line vty 5 15 access-class 23 in privilege level 15 password 7 censored login transport input all line vty 16 1370 password 7 censored login transport input all ! scheduler allocate 20000 1000 end The last problem I'm having is the 3G interfaces go down after only a few minutes of inactivity. I've tried using kron to ping the local HWIC-3G-HSPA interface (cellular 0/1/0) every minute but that hasn't been successful. Manually pinging the IP assigned (by the telco) to ce0/1/0 does bring the interface up. Any ideas? Thanks

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  • Moving a point along a vector

    - by Chris
    Hello- I have a point defined by x,y and a vector defined by heading, speed. I am attempting to move the point x,y along this vector, at a distance of 'speed'. Below is the code I am currently using: self.x += self.speed * cos(self.heading); self.y += self.speed * sin(self.heading); Heading can be any angle in a full circle - 0 to 2p (0-360 degrees). The problem is the above code: Only moves along the x or y axis when angle is 0-270 for example, when the avatar is facing the top-right corner (45 degrees relative), it moves straight up. Does not move at all when angle is 270-360 heading, speed, X and Y are all doubles, and heading is reported by the user touching a direction-pad in the lower corner. I know the heading is correct because the avatar rotates to the correct direction, it is just the actual movement I am having problems with. Thanks for any help - Chris

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  • How can I tell if a CSV is in UTF-7 or UTF-8

    - by dru-zod
    Excel seems to save CSV files in (what I think is) UTF-7, despite the fact that most information I have read suggest that in general, you should not UTF-7. Indeed, other applications (Text pad, which lets me choose) save things in UTF-8 (or Unicode etc, but UTF-7 is not even an option). Using .NET, I read the stream, and have to provide the encoding. If I get it wrong, accented characters are replaced with question marks. If I try and let StreamReader work it out (using detectEncodingFromByteOrderMarks), it gets it wrong (at least, it does if the file has been saved in Excel). It is unlikely that anything other then Excel will be used, so I could just assume UTF-7. Are there any other options? I need to support French (accented), German, Dutch, and Norwegian characters.

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  • Python: Slicing a list into n nearly-equal-length partitions

    - by Drew
    I'm looking for a fast, clean, pythonic way to divide a list into exactly n nearly-equal partitions. partition([1,2,3,4,5],5)->[[1],[2],[3],[4],[5]] partition([1,2,3,4,5],2)->[[1,2],[3,4,5]] (or [[1,2,3],[4,5]]) partition([1,2,3,4,5],3)->[[1,2],[3,4],[5]] (there are other ways to slice this one too) There are several answers in here http://stackoverflow.com/questions/1335392/iteration-over-list-slices that run very close to what I want, except they are focused on the size of the list, and I care about the number of the lists (some of them also pad with None). These are trivially converted, obviously, but I'm looking for a best practice. Similarly, people have pointed out great solutions here http://stackoverflow.com/questions/312443/how-do-you-split-a-list-into-evenly-sized-chunks-in-python for a very similar problem, but I'm more interested in the number of partitions than the specific size, as long as it's within 1. Again, this is trivially convertible, but I'm looking for a best practice.

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  • Traverse list to add elements, C#.

    - by Addie
    I have a list of objects. Each object has an integer quantity and a DateTime variable which contains a month and year value. I'd like to traverse the list and pad the list by adding missing months (with quantity 0) so that all consecutive months are represented in the list. What would be the best way to accomplish this? Example: Original List { Jan10, 3 }, { Feb10, 4 }, { Apr10, 2 }, { May10, 2 }, { Aug10, 3 }, { Sep10, -3 }, { Oct10, 6 }, { Nov10, 3 }, { Dec10, 7 }, { Feb11, 3 } New List { Jan10, 3 }, { Feb10, 4 }, {Mar10, 0}, { Apr10, 2 }, { May10, 2 }, { Jun10, 0 }, { Jul10, 0 } { Aug10, 3 }, { Sep10, -3 }, { Oct10, 6 }, { Nov10, 3 }, { Dec10, 7 }, { Jan11, 0 }, { Feb11, 3 }

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  • Experience with laptop Keyboards?

    - by Omar Kooheji
    I'm thinking of retiring my 3 year old HP laptop I want to know which manufacturor makes laptops with the best Keyboards? I loved my Full width keyboard, with numberic pad on my HP, I've tried a a few laptop keyboards in shops and have found none of them satisfying to type with. What I want is something that will maximise my typing comfort. All the ones I see in shops seem to be designed to look good but feel horible. The keys are either too shiny, too small, or don't press down enough. All I want it a keyboard thats comfortable, I've been given a Lenovo laptop by my work and I've had to resort to pluging in a USB keyboard while I work, which is less than ideal.

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  • Temp file that exists only in RAM?

    - by Auraomega
    I'm trying to write an encrpytion using the OTP method. In keeping with the security theories I need the plain text documents to be stored only in memory and never ever written to a physical drive. The tmpnam command appears to be what I need, but from what I can see it saves the file on the disk and not the RAM. Using C++ is there any (platform independent) method that allows a file to exist only in RAM? I would like to avoid using a RAM disk method if possible. Thanks Edit: Thanks, its more just a learning thing for me, I'm new to encryption and just working through different methods, I don't actually plan on using many of them (esspecially OTP due to doubling the original file size because of the "pad"). If I'm totally honest, I'm a Linux user so ditching Windows wouldn't be too bad, I'm looking into using RAM disks for now as FUSE seems a bit overkill for a "learning" thing.

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  • Logictech USB HID controller message

    - by rross
    I have a Logitech game controller(http://www.amazon.com/Logitech-Dual-Action-Game-Pad/dp/B0000ALFCI). I'm using c# and Microsoft's HID driver to track what buttons are being pressed. Each button press sends a Byte Array that has 8 values. The problems is that I don't know what those 8 value represent. Here is an example: 0, 128, 126, 127, 130, 24, 24, 0, 4, 252 0, 128, 126, 127, 130, 40, 40, 0, 4, 252 0, 128, 126, 127, 127, 72, 72, 0, 4, 252 0, 128, 126, 127, 127, 136, 136, 0, 4, 252 Those are the values of the Byte Array for button press 1, 2, 3, 4 respectively. I see where the values are changing, but I'm unsure what they represent. I'm unable to find any specs on Microsoft HID driver. Can someone point me in the right direction?

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  • Ogg/Vorbis: _ov_fopen cannot be found

    - by knight666
    I'm trying to use Ogg/Vorbis with OpenAL to get sound in my game. Right now I'm simply trying to load a .ogg file and read its data, I'm not actually doing anything with it. I first tried using ov_open, however, the documentation said I should really be using ov_fopen on Windows. However, when I try to use that I get the following: 1>AudioManager.obj : error LNK2019: unresolved external symbol _ov_fopen referenced in function "private: static struct SomeGame::SoundData * __cdecl SomeGame::AudioManager::LoadOGG(char *)" (?LoadOGG@AudioManager@SomeGame@@CAPAUSoundData@2@PAD@Z) ...and when I Google "unresolved external symbol _ov_fopen", I get exactly one result. And it's in Japanese. So I tried downloading the ogg and vorbis source and compiling it, and inserting those in the project, but it still gives me the same error. Basically, how do I load in an Ogg/Vorbis file to be used with OpenAL on Windows? Thanks in advance.

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  • JSF & jqPlot Uncaught TypeError

    - by sdg
    I have a problem using jqPlot with JSF I added this code to my JSF page: $(document).ready(function () { var s1 = [200, 600, 700, 1000]; var s2 = [460, - 210, 690, 820]; var s3 = [-260, - 440, 320, 200]; var ticks = ['May', 'June', 'July', 'August']; var plot1 = $.jqplot('chart1', [s1, s2, s3], { // The "seriesDefaults" option is an options object that will // be applied to all series in the chart. seriesDefaults: { renderer: $.jqplot.BarRenderer, rendererOptions: { fillToZero: true } }, series: [{ label: 'Hotel' }, { label: 'Event Regristration' }, { label: 'Airfare' }], legend: { show: true, placement: 'outsideGrid' }, axes: { xaxis: { renderer: $.jqplot.CategoryAxisRenderer, ticks: ticks }, yaxis: { pad: 1.05, tickOptions: { formatString: '$%d' } } } }); }); but when I try to load the page I got this error : Uncaught TypeError: Cannot read property 'BarRenderer' of undefined (anonymous function)portfolioModeling.xhtml:184 f.extend._Deferred.e.resolveWithjquery.min.js:2 e.extend.readyjquery.min.js:2 c.addEventListener.C I added the whole required js files and also the css file but I am lost and don't know where is the problem Thanks in advance

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  • understanding silverlight resource file format

    - by Quincy
    I'm trying to understand the format of silverlight resource files. There are 4 bytes of the data comes after PAD. I'd like to know what these values are, and how they are generated. here is the hex dump of a .g.resources file. Here is what I know: there is 0xbeefcace at the beginning, then there is dependancies, then padding. after that is the great unknown (but I really like to know). After 4 null bytes, are the file name and size of the resource. and After that is content of the said file. I'm not that familiar with .Net and silverlight resource management. would someone please tell me what the mystical 4 bytes are, or point me the url to the specification doc or something. Any help would be appreciated!

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  • RijndaelManaged Padding when data matches block size

    - by trampster
    If I use PKCS7 padding in RijndaelManaged with 16 bytes of data then I get 32 bytes of data output. It appears that for PKCS7 when the data size matches the block size it adds a whole extra block of data. If I use Zeros padding for 16 bytes of data I get out 16 bytes of data. So for Zeros padding if the data matches the block size then it doesn't pad. I have searched through the documentation and it says nothing about this difference in padding behavior. Can someone please point me to some kind of documentation which specifies what the padding behavior should be for the different padding modes when the data size matches the block size.

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  • Traverse list to add elements using .NET

    - by Addie
    I have a list of objects. Each object has an integer quantity and a DateTime variable which contains a month and year value. I'd like to traverse the list and pad the list by adding missing months (with quantity 0) so that all consecutive months are represented in the list. What would be the best way to accomplish this? Example: Original List { Jan10, 3 }, { Feb10, 4 }, { Apr10, 2 }, { May10, 2 }, { Aug10, 3 }, { Sep10, -3 }, { Oct10, 6 }, { Nov10, 3 }, { Dec10, 7 }, { Feb11, 3 } New List { Jan10, 3 }, { Feb10, 4 }, {Mar10, 0}, { Apr10, 2 }, { May10, 2 }, { Jun10, 0 }, { Jul10, 0 } { Aug10, 3 }, { Sep10, -3 }, { Oct10, 6 }, { Nov10, 3 }, { Dec10, 7 }, { Jan11, 0 }, { Feb11, 3 }

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  • Code Golf: Phone Number to Words

    - by Nick Hodges
    Guidelines for code-golf on SO We've all seen phone numbers that are put into words: 1-800-BUY-MORE, etc. What is the shortest amount of code you can write that will produce all the possible combinations of words for a 7 digit US phone number. Input will be a seven digit integer (or string, if that is simpler), and assume that the input is properly formed. Output will be a list of seven character strings that For instance, the number 428-5246 would produce GATJAGM GATJAGN GATJAGO GATJAHM GATJAHN GATJAHO and so on..... Winning criteria will be code from any language with the fewest characters that produce every possible letter combination. Additional Notes: To make it more interesting, words can be formed only by using the letters on a North American Classic Key Pad phone with three letters per number as defined here.That means that Z and Q are excluded. For the number '1', put a space. For the number '0', put a hyphen '-' Bonus points awarded for recognizing output as real English words. Okay, not really. ;-)

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  • Is it possible to get anti-alias for Font in Rebol Graphics VID ?

    - by Rebol Tutorial
    Anti-alias works for Draw but I can't see how to get anti-alias for font : is it possible anywhow (including hacking rebol vid ...) because font in the picture generated below is not nice: view layout [ box 278x185 effect [ ; default box face size is 100x100 draw [ anti-alias on ; information for the next draw element (not required) line-width 2.5 ; number of pixels in width of the border pen black ; color of the edge of the next draw element fill-pen radial 100x50 5 55 5 10 10 71.0.6 30.10.10 71.0.6 ; the draw element box ; another box drawn as an effect 15 ; size of rounding in pixels 0x0 ; upper left corner 278x170 ; lower right corner ] ] pad 30x-150 Text "Experiment" font [name: "Impact" size: 24 color: white] image http://www.rebol.com/graphics/reb-logo.gif ]

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  • Unix tree convert to recursive php array

    - by Fordnox
    I have a response from remote server like this: /home/computer/Downloads |-- /home/computer/Downloads/Apple | `-- /home/computer/Downloads/Apple/Pad |-- /home/computer/Downloads/Empty_Folder `-- /home/computer/Downloads/Subfolder |-- /home/computer/Downloads/Subfolder/Empty `-- /home/computer/Downloads/Subfolder/SubSubFolder `-- /home/computer/Downloads/Subfolder/SubSubFolder/Test this is the output for command computer@athome:$ tree -df --noreport -L 5 /home/computer/Downloads/ I would like to parse this string to recursive php array or object, something like this. I would show only part of result to get the idea. array( 'title' => '/home/computer/Downloads', 'children' => array( 0 => array( 'title' => '/home/computer/Downloads/Apple', 'children' => array( ... ) ) ); Response from server can change according to scanned directory. Can someone help me write this function. Please note that this is response from remote server and php functions can not scan any remote dir.

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