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  • Remove \r from a string in C++

    - by Werner
    Hi, in a C++ program, there is a point when it reads a string like: "NONAME_1_1\r" the \r is causing me trouble. I guess it prints or adds something like "^M". Is it right? Anyway it casues me problem, and I want to get rid of it. I can not modify the input. I wonder how could I at this point, using C++, and in the easiest way, to remove \r for this string. I know how to do it on bash but no clue on C++. Thanks.

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  • What does the & sign mean in PHP?

    - by jeffkee
    I was trying to find this answer on Google but I guess the symbol & works as some operator, or is just not generally a searchable term for any reason.. anyhow. I saw this code snippet while learning how to create wordpress plugins, so I just need to know what the & means when it precedes a variable that holds a class object. //Actions and Filters if (isset($dl_pluginSeries)) { //Actions add_action('wp_head', array(&$dl_pluginSeries, 'addHeaderCode'), 1); //Filters add_filter('the_content', array(&$dl_pluginSeries, 'addContent')); }

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  • How do you get the email using facebook api?

    - by Marwelln
    I'm using this code but I can't figure out how to get the email from the user. I know you must get special permission from the user but I don't know how. I can get the public data from the user but that's not what I even need. The only thing I need is the email. I guess it's something with this line: $me = $facebook->api('/me'); I have read the documentation but I still don't know how I can get the email. How do I get the email from the user loggin in on my website with the facebook api?

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  • How to turn one server into many servers? (Virtualization/VMWare)

    - by user1229962
    I'm hoping for a high level discussion of this problem I know is quickly approaching my application. I have a server that binds on a specific port and manages TCP Sockets from my clients. I know that it is common practice to use VMWare to virtualize servers and run multiple servers at once. How can a single server design be changed to support multiple servers? Multiple servers can't bind to the same port. If I had to guess I would say a proxy server binds to the port and then sends connections off to the other servers to be handled as if it was still a single server application. I'm wondering what options there are and what are the common practices for solving this problem? Thanks in advance!

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  • Why delete and recreate a querydef object when you can just change the .SQL property?

    - by dblE
    Do you remember the venerable old Microsoft Query by Form (QBF) VBA example from back in the day link that recommended that you delete an existing query and then recreate it dynamically?: On Error Resume Next db.QueryDefs.Delete ("qryResults") On Error GoTo 0 Set qdf = db.CreateQueryDef("qryResults", "SELECT p.*... Why not just change the SQL property of the querydef object? qdf.SQL = "SELECT p.*... I am wondering if anyone knows why the MS engineers wrote an example that suggests that you delete and then recreate a query instead of simply changing the SQL property? I would guess that the act of deleting and recreating objects over time could contribute to corruption and bloating in your front end, not to mention changing the SQL property is so much simpler. Does anyone have more insight into this?

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  • Array help Index out of range exeption was unhandled

    - by Michael Quiles
    I am trying to populate combo boxes from a text file using comma as a delimiter everything was working fine, but now when I debug I get the "Index out of range exeption was unhandled" warning. I guess I need a fresh pair of eyes to see where I went wrong, I commented on the line that gets the error //Fname = fields[1]; using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Drawing.Printing; using System.Linq; using System.Text; using System.Windows.Forms; using System.IO; namespace Sullivan_Payroll { public partial class xEmpForm : Form { bool complete = false; public xEmpForm() { InitializeComponent(); } private void xEmpForm_Resize(object sender, EventArgs e) { this.xCenterPanel.Left = Convert.ToInt16((this.Width - this.xCenterPanel.Width) / 2); this.xCenterPanel.Top = Convert.ToInt16((this.Height - this.xCenterPanel.Height) / 2); Refresh(); } private void exitToolStripMenuItem_Click(object sender, EventArgs e) { //Exits the application this.Close(); } private void xEmpForm_FormClosing(object sender, FormClosingEventArgs e) //use this on xtrip calculator { DialogResult Response; if (complete == true) { Application.Exit(); } else { Response = MessageBox.Show("Are you sure you want to Exit?", "Exit", MessageBoxButtons.YesNo, MessageBoxIcon.Question, MessageBoxDefaultButton.Button2); if (Response == DialogResult.No) { complete = false; e.Cancel = true; } else { complete = true; Application.Exit(); } } } private void xEmpForm_Load(object sender, EventArgs e) { //file sources string fileDept = "source\\Department.txt"; string fileSex = "source\\Sex.txt"; string fileStatus = "source\\Status.txt"; if (File.Exists(fileDept)) { using (System.IO.StreamReader sr = System.IO.File.OpenText(fileDept)) { string dept = ""; while ((dept = sr.ReadLine()) != null) { this.xDeptComboBox.Items.Add(dept); } } } else { MessageBox.Show("The Department file can not be found.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error); } if (File.Exists(fileSex)) { using (System.IO.StreamReader sr = System.IO.File.OpenText(fileSex)) { string sex = ""; while ((sex = sr.ReadLine()) != null) { this.xSexComboBox.Items.Add(sex); } } } else { MessageBox.Show("The Sex file can not be found.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error); } if (File.Exists(fileStatus)) { using (System.IO.StreamReader sr = System.IO.File.OpenText(fileStatus)) { string status = ""; while ((status = sr.ReadLine()) != null) { this.xStatusComboBox.Items.Add(status); } } } else { MessageBox.Show("The Status file can not be found.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error); } } private void xFileSaveMenuItem_Click(object sender, EventArgs e) { { const string fileNew = "source\\New Staff.txt"; string recordIn; FileStream outFile = new FileStream(fileNew, FileMode.Create, FileAccess.Write); StreamWriter writer = new StreamWriter(outFile); for (int count = 0; count <= this.xEmployeeListBox.Items.Count - 1; count++) { this.xEmployeeListBox.SelectedIndex = count; recordIn = this.xEmployeeListBox.SelectedItem.ToString(); writer.WriteLine(recordIn); } writer.Close(); outFile.Close(); this.xDeptComboBox.SelectedIndex = -1; this.xStatusComboBox.SelectedIndex = -1; this.xSexComboBox.SelectedIndex = -1; MessageBox.Show("your file is saved"); } } private void xViewFacultyMenuItem_Click(object sender, EventArgs e) { const string fileStaff = "source\\Staff.txt"; const char DELIM = ','; string Lname, Fname, Depart, Stat, Sex, Salary, cDept, cStat, cSex; double Gtotal; string recordIn; string[] fields; cDept = this.xDeptComboBox.SelectedItem.ToString(); cStat = this.xStatusComboBox.SelectedItem.ToString(); cSex = this.xSexComboBox.SelectedItem.ToString(); FileStream inFile = new FileStream(fileStaff, FileMode.Open, FileAccess.Read); StreamReader reader = new StreamReader(inFile); recordIn = reader.ReadLine(); while (recordIn != null) { fields = recordIn.Split(DELIM); Lname = fields[0]; Fname = fields[1]; // this is where the error appears Depart = fields[2]; Stat = fields[3]; Sex = fields[4]; Salary = fields[5]; Fname = fields[1].TrimStart(null); Depart = fields[2].TrimStart(null); Stat = fields[3].TrimStart(null); Sex = fields[4].TrimStart(null); Salary = fields[5].TrimStart(null); Gtotal = double.Parse(Salary); if (Depart == cDept && cStat == Stat && cSex == Sex) { this.xEmployeeListBox.Items.Add(recordIn); } recordIn = reader.ReadLine(); } reader.Close(); inFile.Close(); if (this.xEmployeeListBox.Items.Count >= 1) { this.xFileSaveMenuItem.Enabled = true; this.xFilePrintMenuItem.Enabled = true; this.xEditClearMenuItem.Enabled = true; } else { this.xFileSaveMenuItem.Enabled = false; this.xFilePrintMenuItem.Enabled = false; this.xEditClearMenuItem.Enabled = false; MessageBox.Show("Records not found"); } } private void xEditClearMenuItem_Click(object sender, EventArgs e) { this.xEmployeeListBox.Items.Clear(); this.xDeptComboBox.SelectedIndex = -1; this.xStatusComboBox.SelectedIndex = -1; this.xSexComboBox.SelectedIndex = -1; this.xFileSaveMenuItem.Enabled = false; this.xFilePrintMenuItem.Enabled = false; this.xEditClearMenuItem.Enabled = false; } } } Source file -- Anderson, Kristen, Accounting, Assistant, Female, 43155 Ball, Robin, Accounting, Instructor, Female, 42723 Chin, Roger, Accounting, Full, Male,59281 Coats, William, Accounting, Assistant, Male, 45371 Doepke, Cheryl, Accounting, Full, Female, 52105 Downs, Clifton, Accounting, Associate, Male, 46887 Garafano, Karen, Finance, Associate, Female, 49000 Hill, Trevor, Management, Instructor, Male, 38590 Jackson, Carole, Accounting, Instructor, Female, 38781 Jacobson, Andrew, Management, Full, Male, 56281 Lewis, Karl, Management, Associate, Male, 48387 Mack, Kevin, Management, Assistant, Male, 45000 McKaye, Susan, Management, Instructor, Female, 43979 Nelsen, Beth, Finance, Full, Female, 52339 Nelson, Dale, Accounting, Full, Male, 54578 Palermo, Sheryl, Accounting, Associate, Female, 45617 Rais, Mary, Finance, Instructor, Female, 27000 Scheib, Earl, Management, Instructor, Male, 37389 Smith, Tom, Finance, Full, Male, 57167 Smythe, Janice, Management, Associate, Female, 46887 True, David, Accounting, Full, Male, 53181 Young, Jeff, Management, Assistant, Male, 43513

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  • Unity3D draw call optimization : static batching VS manually draw mesh with MaterialPropertyBlock

    - by Heisenbug
    I've read Unity3D draw call batching documentation. I understood it, and I want to use it (or something similar) in order to optimize my application. My situation is the following: I'm drawing hundreds of 3d buildings. Each building can be represented using a Mesh (or a SubMesh for each building, but I don't thing this will affect performances) Each building can be textured with several combinations of texture patterns(walls, windows,..). Textures are stored into an Atlas for optimizaztion (see Texture2d.PackTextures) Texture mapping and facade pattern generation is done in fragment shader. The shader can be the same (except for few values) for all buildings, so I'd like to use a sharedMaterial in order to optimize parameters passed to the GPU. The main problem is that, even if I use an Atlas, share the material, and declare the objects as static to use static batching, there are few parameters(very fews, it could be just even a float I guess) that should be different for every draw call. I don't know exactly how to manage this situation using Unity3D. I'm trying 2 different solutions, none of them completely implemented. Solution 1 Build a GameObject for each building building (I don't like very much the overhead of a GameObject, anyway..) Prepare each GameObject to be static batched with StaticBatchingUtility.Combine. Pack all texture into an atlas Assign the parent game object of combined batched objects the Material (basically the shader and the atlas) Change some properties in the material before drawing an Object The problem is the point 5. Let's say I have to assign a different id to an object before drawing it, how can I do this? If I use a different material for each object I can't benefit of static batching. If I use a sharedMaterial and I modify a material property, all GameObjects will reference the same modified variable Solution 2 Build a Mesh for every building (sounds better, no GameObject overhead) Pack all textures into an Atlas Draw each mesh manually using Graphics.DrawMesh Customize each DrawMesh call using a MaterialPropertyBlock This would solve the issue related to slightly modify material properties for each draw call, but the documentation isn't clear on the following point: Does several consecutive calls to Graphic.DrawMesh with a different MaterialPropertyBlock would cause a new material to be instanced? Or Unity can understand that I'm modifying just few parameters while using the same material and is able to optimize that (in such a way that the big atlas is passed just once to the GPU)?

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  • Microsoft, please help me diagnose TFS Administration permission issues!

    - by Martin Hinshelwood
    I recently had a fun time trying to debug a permission issue I ran into using TFS 2010’s TfsConfig. Update 5th March 2010 – In its style of true excellence my company has added rant to its “Suggestions for Better TFS”. <rant> I was trying to run the TfsConfig tool and I kept getting the message: “TF55038: You don't have sufficient privileges to run this tool. Contact your Team Foundation system administrator." This message made me think that it was something to do with the Install permissions as it is always recommended to use a single account to do every install of TFS. I did not install the original TFS on our network and my account was not used to do the TFS2010 install. But I did do the upgrade from 2010 beta 2 to 2010 RC with my current account. So I proceeded to do some checking: Am I in the administrators group on the server? Figure: Yes, I am in the administrators group on the server Am I in the Administration Console users list? Figure: Yes, I am in the Administration Console users list Have I reapplied the permissions in the Administration Console users list ticking all the options? Figure: Make sure you check all of the boxed if you want to have all the admin options Figure: Yes, I have made sure that all my options are correct. Am I in the Team Foundation administrators group? Figure: Yes, I am in the Team Foundation Administrators group Is my account explicitly SysAdmin on the Database server? Figure: Yes, I do have explicit SysAdmin on the database Can you guess what the problem was? The command line window was not running as the administrator! As with most other applications there should be an explicit error message that states: "You are not currently running in administrator mode; please restart the command line with elevated privileges!" This would have saved me 30 minutes, although I agree that I should change my name to Muppet and just be done with it. </rant>   Technorati Tags: Visual Studio ALM,Administration,Team Foundation Server Admin Console,TFS Admin Console

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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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  • The right way of using index.html

    - by Jeyekomon
    I have quite a lot of issues I'd like to hear your opinion on, so I hope I'll manage to explain it well enough. I should also note that I'm beginner equipped only with the knowledge of HTML and CSS so although I'm almost sure that there is a simple solution using powerful PHP, it won't help me. Let's say that I have my personal blog on the address example.com/blog.html and there are links to several sub-blogs example.com/blog/math.html, example.com/blog/coding.html etc. So my root folder contains blog.html and blog folder, the blog folder itself contains files math.html and coding.html. First of all, I learned (from Google Webmasters Tools) that for SEO and aesthetical purposes it's good to unify example.com.com and example.com/index.html by adding _rel="canonical"_ attribute into the source of the index.html. Using a couple of other tricks (like linking to ../ and ./) I got rid of the ugly index.html appearing in my web addresses. And now I wonder if this trick can be used not only for the root folder but for any folder? I mean, I would move my blog.html into the blog folder, rename it into the index.html and add rel="canonical" to unify example.com/blog/index.html with example.com/blog/. This trick would change the address of my blog from example.com/blog.html into example.com/blog/. Not finished! I'm also experiencing problems with the google robot indexing my folders. So when I type site:example.com/ into the google search, the link to my folder example.com/blog/ with raw files, icons etc. appears among the other results. I guess there are also other ways how to fix it, but IMHO the change mentioned above would do the trick too - the index.html in the blog folder would preserve the user from viewing the actual raw content of that folder, there would appear only the right link example.com/blog/ in the google search and (I hope that) _rel="canonical"_ would make the second, unwanted link example.com/blog/index.html not to appear in the search results. So my questions are: Is it a good practice to have the index.html file in every subfolder or is it intended to be only in the root folder? Are there any disadvantages or problems that may occur when using the second, "index in every folder" method? Which one of the two ways of structuring the website described above would you prefer?

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  • Emperors don’t come cheap

    - by RoyOsherove
    “Sorry” I replied in a polite email. “Maybe next year, when budgets allow for this”. It was addressed to the organizer of TechEd US, which was to be in New Orleans this year. Man, I would have loved to be in new Orleans this year, but, I guess these guys only understand one language – and I won’t be their puppy any more. You see, they wouldn’t pay for my business class flight to TechEd from Israel. Me– the great emperor of unit testing?! travelling coach for 12 hours? No thanks. I have better things to do! And this is after last year, they only invited me to have one talk throughout the conference. one talk. After the year before I was on the top ten speakers list of that conference?! No sir! They did give it a good try, though. They said they can pay up to 4,000$ per flight cost for me, and that they only found a flight at about 5460$. “Unacceptable” I told them when they asked if I would pay the difference. And that was that. Goodbye teched. As I closed up gmail, wondering if I should have told them that I found a similar flight at 4,300$, and came back to the living room, I told my wife, all full of myself “I just canceled teched”. “Oh good” she said. Not even looking at me as she tried to feed our one year old. “did you tell them you need to cancel because you already have another flight that month and your wife won’t let you travel more than once a month anymore?” “Yeah right” I said. Just what I need – for people to realize I’m totally whipped. I still need an ounce of dignity. “I told those bastards that if they want me they have to make an effort. People like me don’t come cheap, you know?” “You’re an idiot for not telling them the real reason.” She handed me the baby.  “What if they found a flight that matches their budget? How would you have gotten away from that engagement?” . She put on “Lost” on the media center and sat next to me. I did not reply.

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  • Measuring Social Media Efforts

    - by David Dorf
    So you're on the bandwagon and you've created a Facebook page, you're tweeting everyday, and maybe you've even got a YouTube channel. Now what? After you put any program in place, you need to measure, set new goals, then execute and this is no different. But how does one measure social media efforts? First, I guess we need some goals. Typical ones might be to acquire customers, engage them, then convert them. So that translates to: Increase Facebook fans and Twitter followers Increase comments/posting and retweets Increase redemption of offers via Facebook and Twitter Counting fans and followers is easy, and tracking the redemption of coupons isn't that hard either, but measuring engagement is a tough one. How do you know whether your fans are reading your posts, and whether your posts have any meaning to them? For Facebook, the fan page administrator has access to analytics called Facebook Insights. There you can check weekly metrics such as total fans, new fans, lost fans, demographics of fans, number of postings, numbers clicks, etc. Not nearly as comprehensive as Google Analytics, but well on its way. For Twitter, getting information is a little tougher. Again, its easy to track followers and you can use tools like TweetMeme to encourage and track retweets. An interesting website called WeFollow tries to measure influence for certain topics. For example, the top three influencers for the topic "retail" are retailweek, retailwire, and retailerdaily. Other notables are #10 BestBuy, #11 GapOfficial, #12 JeffPR, and #17 OracleRetail. I assume influence is calculated based on number of followers, number of retweets, frequency of tweets, and perhaps depth of dialogs. If you want to get serious about monitoring and measuring social marketing efforts, you'd be wise to invest in a strong tool. Several are listed on this wiki, including big ones like Radian6, Nielsen, Omniture, and Buzzient. Buzzient might be particularly interesting because its integrated with Oracle CRM OnDemand -- see the demo. As always, I'm interested in hearing how others approach goal setting and monitoring of social media efforts, so feel free to post comments.

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  • Don&rsquo;t Forget! In-Memory Databases are Hot

    - by andrewbrust
    If you’re left scratching your head over SAP’s intention to acquire Sybase for almost $6 million, you’re not alone.  Despite Sybase’s 1990s reign as the supreme database standard in certain sectors (including Wall Street), the company’s flagship product has certainly fallen from grace.  Why would SAP pay a greater than 50% premium over Sybase’s closing price on the day of the announcement just to acquire a relational database which is firmly stuck in maintenance mode? Well there’s more to Sybase than the relational database product.  Take, for example, its mobile application platform.  It hit Gartner’s “Leaders’ Quadrant” in January of last year, and SAP needs a good mobile play.  Beyond the platform itself, Sybase has a slew of mobile services; click this link to look them over. There’s a second major asset that Sybase has though, and I wonder if it figured prominently into SAP’s bid: Sybase IQ.  Sybase IQ is a columnar database.  Columnar databases place values from a given database column contiguously, unlike conventional relational databases, which store all of a row’s data in close proximity.  Storing column values together works well in aggregation reporting scenarios, because the figures to be aggregated can be scanned in one efficient step.  It also makes for high rates of compression because values from a single column tend to be close to each other in magnitude and may contain long sequences of repeating values.  Highly compressible databases use much less disk storage and can be largely or wholly loaded into memory, resulting in lighting fast query performance.  For an ERP company like SAP, with its own legacy BI platform (SAP BW) and the entire range of Business Objects and Crystal Reports BI products (which it acquired in 2007) query performance is extremely important. And it’s a competitive necessity too.  QlikTech has built an entire company on a columnar, in-memory BI product (QlikView).  So too has startup company Vertica.  IBM’s TM1 product has been doing in-memory OLAP for years.  And guess who else has the in-memory religion?  Microsoft does, in the form of its new PowerPivot product.  I expect the technology in PowerPivot to become strategic to the full-blown SQL Server Analysis Services product and the entire Microsoft BI stack.  I sure don’t blame SAP for jumping on the in-memory bandwagon, if indeed the Sybase acquisition is, at least in part, motivated by that. It will be interesting to watch and see what SAP does with Sybase’s product line-up (assuming the acquisition closes), including the core database, the mobile platform, IQ, and even tools like PowerBuilder.  It is also fascinating to watch columnar’s encroachment on relational.  Perhaps this acquisition will be columnar’s tipping point and people will no longer see it as a fad.  Are you listening Larry Ellison?

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  • Silverlight Cream for March 10, 2010 -- #810

    - by Dave Campbell
    In this Issue: Andrea Boschin, Jeremy Likness(-2-), Andrew Veresov, Nokola, SilverLaw, Gill Cleeren, Jim Wightman and Jeremy Likness, Viktor Larsson(-2-), and Walter Ferrari. Shoutouts: Viktor Larsson has a post up about Silverlight Market Penetration ... hope to meet you at MIX10, Viktor! Gergely Orosz has posted the Slides and code for the presentation “An Introduction to Silverlight” It appears that if I miss a day, I can pretty much do an all-submittal post :) From SilverlightCream.com: Writing an AsyncLoader to enqueue long running operations Andrea Boschin has a tutorial on SilverlightShow where he's building up an asynch service to deal with a long-running app on the server. MVVM with MEF in Silverlight: Video Tutorial Jeremy Likness has a video tutorial up for helping beginners wire up MVVM and MEF to Silverlight. Source code for the app in the video is downloadable. MVVM with MEF in Silverlight Video Tutorial Part 2: Plugins and Metadata In part 2, Jeremy Likness redesigns the app using metadata to turn the shapes into objects, and then show how easy it is to add a new plugin... and the source for the app is downloadable. Binding a Converter Parameter Andrew Veresov has a nice code-filled solution up for those times that you need to bind a ConverterParameter value. EasyPainter: Lion Hair styling Nokola has not been idle with Easy Painter... now he's added "Lion Hair" to the list of stylings you can apply... guess if you want to change someone's 'mane' ... sorry! Twisting Navigation - Silverlight 3 SilverLaw has another control up - a "Twisting Navigation" control... very cool :) ... and since I'm behind the curve, he already has an update in the Expression Gallery as noted in his post, and a video tutorial on implementing it in an application... and if you understand German, turn up the sound :) Uploading and downloading images using a WCF service with Silverlight Gill Cleeren has a tutorial up at SilverlightShow on uploading and downloading images using WCF Services in Silverlight New Windows Phone 7 Community Developer Hub Jim Wightman and Jeremy Likness have a very cool Silverlight page up where you can paste the URL of your XAP in and have it display in a "Windows 7 Series Phone" ... and that's all I'm saying about that. XAML Transformation 101 Viktor Larsson is discussing Transforms in XAML and has a nice tutorial up that is easily the beginning of a carousel... you may also want to check out his other posts... I'm adding him to my list. Silverlight 4 Webcam Demo In this post, Viktor Larsson has a tutorial up for using the WebCam. This is from a beginner perspective, so if you haven't jumped in, now's a good time. How to extend Bing Maps Silverlight with an elevation profile graph - Part 1 Walter Ferrari has a post up at SilverlightShow discussing extensions to BingMaps such as creating routes using GeoCoding and Route Services plus drawing lines on the maps and getting coordinates of the points. Stay in the 'Light! Twitter SilverlightNews | Twitter WynApse | WynApse.com | Tagged Posts | SilverlightCream Join me @ SilverlightCream | Phoenix Silverlight User Group Technorati Tags: Silverlight    Silverlight 3    Silverlight 4    MIX10

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  • UV texture mapping with perspective correct interpolation

    - by Twodordan
    I am working on a software rasterizer for educational purposes and I am having issues with the texturing. The problem is, only one face of the cube gets correctly textured. The rest are stretched edges: You can see the running program online here. I have used cartesian coordinates, and all I do is interpolate the uv values along the scanlines. The general formula I use for interpolating the uv coordinates is pretty much the one I use for the z-buffering interpolation and looks like this (in this case for horizontal scanlines): u_Slope = (right.u - left.u) / (triangleRight_x - triangleLeft_x); v_Slope = (right.v - left.v) / (triangleRight_x - triangleLeft_x); //[...] new_u = left.u + ((currentX_onScanLine - triangleLeft_x) * u_Slope); new_v = left.v + ((currentX_onScanLine - triangleLeft_x) * v_Slope); Then, when I add each point to the pixel buffer, I restore z and uv: z = (1/z); uv.u = Math.round(uv.u * z *100);//*100 because my texture is 100x100px uv.v = Math.round(uv.v * z *100); Then I turn the u v indexes into one index in order to fetch the correct pixel from the image data (which is a 1 dimensional px array): var index = texture.width * uv.u + uv.v; //and the rest is unimportant imagedata[index].RGBA bla bla The interpolation formula is correct considering the consistency of the texture (including the straight stripes). However, I seem to get quite a lot of 0 values for either u or v. Which is probably why I only get one face right. Furthermore, why is the texture flipped horizontally? (the "1" is flipped) I must get some sleep now, but before I get into further dissecting of every single value to see what goes wrong, Can someone more experienced guess why might this be happening, just by looking at the cube? "I have no idea what I'm doing" (it's my first time implementing a rasterizer). Did I miss an important stage? Thanks for any insight. PS: My UV values are as follows: { u:0, v:0 }, { u:0, v:0.5 }, { u:0.5, v:0.5 }, { u:0.5, v:0 }, { u:0, v:0 }, { u:0, v:0.5 }, { u:0.5, v:0.5 }, { u:0.5, v:0 }

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  • E 2.0 Value Metaphors

    - by Tom Tonkin
    I guess I have been doing this too long. I can easily see the value of Enterprise 2.0 technology for an organization, but find it a challenge at times to convey that same value to others. I also know that I'm not the only one that has that issue. Others, that have that same passion, also suffer from being, perhaps, too close to the market. I was having this same discussion with a few colleagues when one of them suggested that metaphors might be a good vehicle to communicate the value to those that are not as familiar.  One such metaphor was discussed.Apparently,back in the early 50's, there was a great Air Force aviator and military strategist by the name of John Boyd.  Without going into a ton of detail (you can search him on the internet), what made Colonel Boyd great was that he never lost a dog fight.  As a matter of fact, they called him 'Forty-Second Boyd' since he claimed to be able to beat anyone in any type of aircraft in less than forty seconds, even if his aircraft was inferior to his opponents.His approach as was unique.  He observed over time that there was a pattern on how aviators  engaged in a dogfight.  He called this method OODA.   It describes how a person or, in our case, an organization, would react to an event.  OODA is an acrostic for Observation, Orientation, Decision and Action.  Again, there is a lot more on the internet about this.A pilot would go through this loop several times during a dogfight and Boyd would try to predict this loop and interrupt it by changing the landscape of the actual dogfight.  This would give Boyd an advantage and be able to predict what his opponent would do and then counterattack.Boyd went on to say that many companies have a similar reaction loop and that by understanding that loop, organizations would be able to adjust better to market conditions, predict what the competition is doing and reposition themselves to gain competitive advantages. So, our metaphor would be that Enterprise 2.0 provides companies greater visibility of their business by connecting to employees, customers and partners in a collaborative fashion.  This, in turn, helps them navigate through the tough times and provide lines of sight to more innovative ideas.  Innovation is that last tool for companies to achieve competitive advantage (maybe a discusion for another post).Perhaps this is more wordy than some other metaphor, but it does allow for an interesting  dialogue to start and maybe even a framwork to fullfill the promise of E 2.0. So, I'm sure there are many more metaphors for the value that E 2.0 brings to organzaitons. Do you have one to share? Please comment below and thanks for stopping by.

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  • Tom Cruise: Meet Fusion Apps UX and Feel the Speed

    - by ultan o'broin
    Unfortunately, I am old enough to remember, and now to admit that I really loved, the movie Top Gun. You know the one - Tom Cruise, US Navy F-14 ace pilot, Mr Maverick, crisis of confidence, meets woman, etc., etc. Anyway, one of more memorable lines (there were a few) was: "I feel the need, the need for speed." I was reminded of Tom Cruise recently. Paraphrasing a certain Senior Vice President talking about Oracle Fusion Applications and user experience at an all-hands meeting, I heard that: Applications can never be too easy to use. Performance can never be too fast. Developers, assume that your code is always "on". Perfect. You cannot overstate the user experience importance of application speed to users, or at least their perception of speed. We all want that super speed of execution and performance, and increasingly so as enterprise users bring the expectations of consumer IT into the work environment. Sten Vesterli (@stenvesterli), an Oracle Fusion Applications User Experience Advocate, also addressed the speed point artfully at an Oracle Usability Advisory Board meeting in Geneva. Sten asked us that when we next Googled something, to think about the message we see that Google has found hundreds of thousands or millions of results for us in a split second (for example, About 8,340,000 results (0.23 seconds)). Now, how many results can we see and how many can we use immediately? Yet, this simple message communicating the total results available to us works a special magic about speed, delight, and excitement that Google has made its own in the search space. And, guess what? The Oracle Application Development Framework table component relies on a similar "virtual performance boost", says Sten, when it displays the first 50 records in a table, and uses a scrollbar indicating the total size of the data record set. The user scrolls and the application automatically retrieves more records as needed. Application speed and its perception by users is worth bearing in mind the next time you're at a customer site and the IT Department demands that you retrieve every record from the database. Just think of... Dave Ensor: I'll give you all the rows you ask for in one second. If you promise to use them. (Again, hat tip to Sten.) And then maybe think of... Tom Cruise. And if you want to read about the speed of Oracle Fusion Applications, and what that really means in terms of user productivity for your entire business, then check out the Oracle Applications User Experience Oracle Fusion Applications white papers on the usable apps website.

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  • UnsatisfiedLinkError on xawt when running HEC-HMS.sh

    - by G.Oxsen
    I am a recent adopter of Linux and this problem has got me stumped. I use HEC-HMS and HEC-DSSVue for work on a regular basis. I have been using the widows versions in wine but they are really buggy. So I decided to try out the linux versions. the links below will take you to the download pages for these two programs. They are free programs for Hydrology and data management. Once I install them and attempt to run the shell file (HEC-HMS.sh for example) I get a ton of java errors that I do not understand. If I had to guess I would say that the java files in question can not be found. When I check to see if java is installed it is. Here is the output from the terminal from trying to run HEC-HMS.sh: Exception in thread "Thread-1" java.lang.UnsatisfiedLinkError: /home/smythe/HEC/hec-hms35/java/lib/i386/xawt/libmawt.so: libXtst.so.6: cannot open shared object file: No such file or directory at java.lang.ClassLoader$NativeLibrary.load(Native Method) at java.lang.ClassLoader.loadLibrary0(Unknown Source) at java.lang.ClassLoader.loadLibrary(Unknown Source) at java.lang.Runtime.load0(Unknown Source) at java.lang.System.load(Unknown Source) at java.lang.ClassLoader$NativeLibrary.load(Native Method) at java.lang.ClassLoader.loadLibrary0(Unknown Source) at java.lang.ClassLoader.loadLibrary(Unknown Source) at java.lang.Runtime.loadLibrary0(Unknown Source) at java.lang.System.loadLibrary(Unknown Source) at sun.security.action.LoadLibraryAction.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at sun.awt.NativeLibLoader.loadLibraries(Unknown Source) at sun.awt.DebugHelper.<clinit>(Unknown Source) at java.awt.Component.<clinit>(Unknown Source) at javax.swing.ImageIcon.<clinit>(Unknown Source) at hms.i.c(Unknown Source) at hms.i.b(Unknown Source) at hms.K.run(Unknown Source) at java.lang.Thread.run(Unknown Source) Exception in thread "Thread-4" java.lang.UnsatisfiedLinkError: /home/smythe/HEC/hec-hms35/java/lib/i386/xawt/libmawt.so: libXtst.so.6: cannot open shared object file: No such file or directory at java.lang.ClassLoader$NativeLibrary.load(Native Method) at java.lang.ClassLoader.loadLibrary0(Unknown Source) at java.lang.ClassLoader.loadLibrary(Unknown Source) at java.lang.Runtime.load0(Unknown Source) at java.lang.System.load(Unknown Source) at java.lang.ClassLoader$NativeLibrary.load(Native Method) at java.lang.ClassLoader.loadLibrary0(Unknown Source) at java.lang.ClassLoader.loadLibrary(Unknown Source) at java.lang.Runtime.loadLibrary0(Unknown Source) at java.lang.System.loadLibrary(Unknown Source) at sun.security.action.LoadLibraryAction.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at java.awt.Toolkit.loadLibraries(Unknown Source) at java.awt.Toolkit.<clinit>(Unknown Source) at sun.print.CUPSPrinter.<clinit>(Unknown Source) at sun.print.UnixPrintServiceLookup.getDefaultPrintService(Unknown Source) at sun.print.UnixPrintServiceLookup.refreshServices(Unknown Source) at sun.print.UnixPrintServiceLookup$PrinterChangeListener.run(Unknown Source) Exception in thread "main" java.lang.NoClassDefFoundError: Could not initialize class java.awt.Toolkit at java.awt.Color.<clinit>(Unknown Source) at hms.model.l.<init>(Unknown Source) at hms.model.ProjectManager.<init>(Unknown Source) at hms.Hms.<init>(Unknown Source) at hms.Hms.main(Unknown Source) Exception in thread "Thread-2" java.lang.NoClassDefFoundError: Could not initialize class sun.print.CUPSPrinter at sun.print.UnixPrintServiceLookup.getDefaultPrintService(Unknown Source) at javax.print.PrintServiceLookup.lookupDefaultPrintService(Unknown Source) at hms.util.f.run(Unknown Source) at java.lang.Thread.run(Unknown Source) I get similar outputs when I try to run HEC-DSSVue.sh. If anyone could shed some light on a solution I would really appreciate it. The problem turned out to be that the program needed 32 bit versions of the particular dependencies.

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  • First impressions of Scala

    - by Scott Weinstein
    I have an idea that it may be possible to predict build success/failure based on commit data. Why Scala? It’s a JVM language, has lots of powerful type features, and it has a linear algebra library which I’ll need later. Project definition and build Neither maven or the scala build tool (sbt) are completely satisfactory. This maven **archetype** (what .Net folks would call a VS project template) mvn archetype:generate `-DarchetypeGroupId=org.scala-tools.archetypes `-DarchetypeArtifactId=scala-archetype-simple `-DremoteRepositories=http://scala-tools.org/repo-releases `-DgroupId=org.SW -DartifactId=BuildBreakPredictor gets you started right away with “hello world” code, unit tests demonstrating a number of different testing approaches, and even a ready made `.gitignore` file - nice! But the Scala version is behind at v2.8, and more seriously, compiling and testing was painfully slow. So much that a rapid edit – test – edit cycle was not practical. So Lab49 colleague Steve Levine tells me that I can either adjust my pom to use fsc – the fast scala compiler, or use sbt. Sbt has some nice features It’s fast – it uses fsc by default It has a continuous mode, so  `> ~test` will compile and run your unit test each time you save a file It’s can consume (and produce) Maven 2 dependencies the build definition file can be much shorter than the equivalent pom (about 1/5 the size, as repos and dependencies can be declared on a single line) And some real limitations Limited support for 3rd party integration – for instance out of the box, TeamCity doesn’t speak sbt, nor does IntelliJ IDEA Steeper learning curve for build steps outside the default Side note: If a language has a fast compiler, why keep the slow compiler around? Even worse, why make it the default? I choose sbt, for the faster development speed it offers. Syntax Scala APIs really like to use punctuation – sometimes this works well, as in the following map1 |+| map2 The `|+|` defines a merge operator which does addition on the `values` of the maps. It’s less useful here: http(baseUrl / url >- parseJson[BuildStatus] sure you can probably guess what `>-` does from the context, but how about `>~` or `>+`? Language features I’m still learning, so not much to say just yet. However case classes are quite usefull, implicits scare me, and type constructors have lots of power. Community A number of projects, such as https://github.com/scalala and https://github.com/scalaz/scalaz are split between github and google code – github for the src, and google code for the docs. Not sure I understand the motivation here.

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  • MAXDOP in SQL Azure

    - by Herve Roggero
    In my search of better understanding the scalability options of SQL Azure I stumbled on an interesting aspect: Query Hints in SQL Azure. More specifically, the MAXDOP hint. A few years ago I did a lot of analysis on this query hint (see article on SQL Server Central:  http://www.sqlservercentral.com/articles/Configuring/managingmaxdegreeofparallelism/1029/).  Here is a quick synopsis of MAXDOP: It is a query hint you use when issuing a SQL statement that provides you control with how many processors SQL Server will use to execute the query. For complex queries with lots of I/O requirements, more CPUs can mean faster parallel searches. However the impact can be drastic on other running threads/processes. If your query takes all available processors at 100% for 5 minutes... guess what... nothing else works. The bottom line is that more is not always better. The use of MAXDOP is more art than science... and a whole lot of testing; it depends on two things: the underlying hardware architecture and the application design. So there isn't a magic number that will work for everyone... except 1... :) Let me explain. The rules of engagements are different. SQL Azure is about sharing. Yep... you are forced to nice with your neighbors.  To achieve this goal SQL Azure sets the MAXDOP to 1 by default, and ignores the use of the MAXDOP hint altogether. That means that all you queries will use one and only one processor.  It really isn't such a bad thing however. Keep in mind that in some of the largest SQL Server implementations MAXDOP is usually also set to 1. It is a well known configuration setting for large scale implementations. The reason is precisely to prevent rogue statements (like a SELECT * FROM HISTORY) from bringing down your systems (like a report that should have been running on a different in the first place) and to avoid the overhead generated by executing too many parallel queries that could cause internal memory management nightmares to the host Operating System. Is summary, forcing the MAXDOP to 1 in SQL Azure makes sense; it ensures that your database will continue to function normally even if one of the other tenants on the same server is running massive queries that would otherwise bring you down. Last but not least, keep in mind as well that when you test your database code for performance on-premise, make sure to set the DOP to 1 on your SQL Server databases to simulate SQL Azure conditions.

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  • Is SugarCRM really adequate for custom development?

    - by dukeofgaming
    I used SugarCRM for a project about two years ago, I ran into errors from the very installation, having to hack the actual installation file to deploy the software in the server... and other erros that I can't recall now. Two years after, I'm picking it up for a project once again... oh dear, I'm feeling like I should have developed the whole thing from scratch myself. Some examples: I couldn't install it in the server (again)... I had to install it locally, then copy the files and database over to the server and manually edit the config file. Constantly getting deployment errors from the module builder... one reason is SugarCRM keeps creating a record in the upgrade_history table for a file that does not exist, I keep deleting such record and it keeps coming back corrupt. I get other deployment errors, but have not figured them out... then I have to rollback all files and database to try again. I deleted a custom module with relationships, the relationships stayed in the other modules and cannot be deleted anymore, PHP warnings all over the place. Quick create for custom modules does not appear, hack needed. Its whole cache directory is a joke, permanent data/files are stored there. The module builder interface disappears required fields. Edit the wrong thing, module builder won't deploy again... then pray Quick Repair and/or Rebuild Relationships do the trick. My impression of SugarCRM now is that, regardless of its pretty exterior and apparent functionality, it is a very low quality piece of software. This even scared me more: http://amplicate.com/hate/sugarcrm; a quote: I wis this info had been available when I tried to implement it 2 years ago... I searched high and low and the only info I found was positive. Yes, it's a piece of crap. The community edition was full of bugs... nothing worked. Essentially I got fired for implementing it. I'm glad though, because now I work for myself, am much happier and make more money... so, I should really thank SugarCRM for sucking so much I guess! I figured that perhaps some of you have had similar experiences, and have either sticked with SugarCRM or moved on to another solution. I'm very interested in knowing what your resolutions were -or your current situations are- to make up my own mind, since the project I'm working on is long term and I'm feeling SugarCRM will be more an obstacle than an aid. Thanks in advance.

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  • Mono for Android Book has been Released!!!!!

    - by Wallym
    If I understand things correctly, and I make no guarantees that I do, our Mono for Android book has been RELEASED!  I'm not quite sure what this means, but my guess is that that it has been printed and is being shipped to various book sellers.So, if you have pre-ordered a copy, its now up to Amazon to send it to you.  Its fully out of my control, Wrox, Wiley, as well as everyone but Amazon.If you haven't bought a copy already, why?  Seriously, go order 8-10 copies for the ones you love.  They'll make great romantic gifts for the ones you love.  Just think at the look on the other person's face when you give them a copy of our book. Here's a little about the book:The wait is over! For the millions of .NET/C# developers who have been eagerly awaiting the book that will guide them through the white-hot field of Android application programming, this is the book. As the first guide to focus on Mono for Android, this must-have resource dives into writing applications against Mono with C# and compiling executables that run on the Android family of devices.Putting the proven Wrox Professional format into practice, the authors provide you with the knowledge you need to become a successful Android application developer without having to learn another programming language. You'll explore screen controls, UI development, tables and layouts, and MonoDevelop as you become adept at developing Android applications with Mono for Android.Develop Android apps using tools you already know—C# and .NETAimed at providing readers with a thorough, reliable resource that guides them through the field of Android application programming, this must-have book shows how to write applications using Mono with C# that run on the Android family of devices. A team of authors provides you with the knowledge you need to become a successful Android application developer without having to learn another programming language. You'll explore screen controls, UI development, tables and layouts, and MonoDevelop as you become adept at planning, building, and developing Android applications with Mono for Android.Professional Android Programming with Mono for Android and .NET/C#:Shows you how to use your existing C# and .NET skills to build Android appsDetails optimal ways to work with data and bind data to controlsExplains how to program with Android device hardwareDives into working with the file system and application preferencesDiscusses how to share code between Mono for Android, MonoTouch, and Windows® Phone 7Reveals tips for globalizing your apps with internationalization and localization supportCovers development of tablet apps with Android 4Wrox Professional guides are planned and written by working programmers to meet the real-world needs of programmers, developers, and IT professionals. Focused and relevant, they address the issues technology professionals face every day. They provide examples, practical solutions, and expert education in new technologies, all designed to help programmers do a better job.Now, go buy a bunch of copies!!!!!If you are interested in iPhone and Android and would like to get a little more knowledgeable in the area of development, you can purchase the 3 pack of books from Wrox on Mobile Development with Mono.  This will cover MonoTouch, Mono for Android, and cross platform methods for using both tools.  A great package in and of itself.  The name of that package is: Wrox Cross Platform Android and iOS Mobile Development Three-Pack 

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  • Should I be using a JavaScript SPA designed when security is important

    - by ryanzec
    I asked something kind of similar on stackoverflow with a particular piece of code however I want to try to ask this in a broader sense. So I have this web application that I have started to write in backbone using a Single Page Architecture (SPA) however I am starting to second guess myself because of security. Now we are not storing and sending credit card information or anything like that through this web application but we are storing sensitive information that people are uploading to us and will have the ability to re-download too. The obviously security concern that I have with JavaScript is that you can't trust anything that comes from JavaScript however in a Backbone SPA application, everything is being sent through JavaScript. There are two security features that I will have to build in JavaScript; permissions and authentication. The authentication piece is just me override the Backbone.Router.prototype.navigate method to check the fragment it is trying to load and if the JavaScript application.session.loggedIn is not set to true (and they are not viewing a none authenticated page), they are redirected to the login page automatically. The user could easily modify application.session.loggedIn to equal true (or modify Backbone.Router.prototype.navigate method) but then they would also have to not so easily dynamically embedded a link into the page (or modify a current one) that has the proper classes, data-* attributes, and href values to then load a page that should only be loaded when they user has logged in (and has the permissions). So I have an acl object that deals with the permissions stuff. All someone would have to do to view pages or parts of pages they should not be able to is to call acl.addPermission(resource, permission) with the proper permissions or modify the acl.hasPermission() to always return true and then navigate away and then back to the page. Now certain things is EMCAScript 5 like Object.seal() or Object.freeze() would help with some of this however we have to support IE 8 which does not support those pieces of functionality. Now the REST API also performs security checks on every request so technically even if they are able to see parts of the interface that they should not be able to, they still should not be able to actually affect any data. The main benefits for me in developing a JavaScript SPA application is that the application is a lot more responsive since it is only transferring the minimum amount of JSON data for the requested action and performing the minimum amount of work too. There are also other things that I think are beneficial like you are going to have to develop an API for the data (which is good if you want expand your application to different platforms/technologies) or their is more of a separation between front-end and back-end however if security is a concern, it is really wise to go down the road of a JavaScript SPA application for the front-end?

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  • Exploding maps in Reporting Services 2008 R2

    - by Rob Farley
    Kaboom! Well, that was the imagery that secretly appeared in my mind when I saw “USA By State Exploded” in the list of installed maps in Report Builder 3.0 – part of the spatial offering of SQL Server Reporting Server 2008 R2. Alas, it just means that the borders are bigger. Clicking on it showed me. Unfortunately, I’m not interested in maps of the US. None of my clients are there (at least, not yet – feel free to get in touch if you want to change this ‘feature’ of my company). So instead, I’ve recently been getting hold of some data for Australian areas. I’ve just bought some PostCode shapes for South Australia, and will use this in demos for conferences and for showing clients how this kind of report can really impact their reporting. One of the companies I was talking about getting shape files sent me a sample. So I chose the “ESRI shapefile” option you see above, and browsed to my file. It appeared in the window like this: Australians will immediately recognise this as the area around Wollongong, just south of Sydney. Well, apart from me. I didn’t. I had to put a Bing Maps layer behind it to work that out, but that’s not for this post. The thing that I discovered was that if I selected the Exploded USA option (but without clicking Next), and then chose my shape file, then my area around Wollongong would be exploded too! Huh! I think this is actually a bug, but a potentially useful one! Some further investigation (involving creating two identical reports, one with this exploded view, one without), showed that the Exploded View is done by reducing the ScaleFactor property of the PolygonLayer in the map control. The Exploded version has it below 1. If you set to above one, your shapes overlap. I discovered this by accident… I guess I hadn’t looked through all the PolygonLayer options to work out what they all do. And because this post is about Reporting, it can qualify for this month’s T-SQL Tuesday, hosted by Aaron Nelson (@sqlvariant). Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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  • SQL SERVER – DVM sys.dm_os_sys_info Column Name Changed in SQL Server 2012

    - by pinaldave
    Have you ever faced situation where something does not work and when you try to go and fix it – you like fixing it and started to appreciate the breaking changes. Well, this is exactly I felt yesterday. Before I begin my story of yesterday I want to state it candidly that I do not encourage anybody to use * in the SELECT statement. One of the my DBA friend who always used my performance tuning script yesterday sent me email asking following question - “Every time I want to retrieve OS related information in SQL Server – I used DMV sys.dm_os_sys_info. I just upgraded my SQL Server edition from 2008 R2 to SQL Server 2012 RC0 and it suddenly stopped working. Well, this is not the production server so the issue is not big yet but eventually I need to resolve this error. Any suggestion?” The funny thing was original email was very long but it did not talk about what is the exact error beside the query is not working. I think this is the disadvantage of being too friendly on email sometime. Well, never the less, I quickly looked at the DMV on my SQL Server 2008 R2 and SQL Server 2012 RC0 version. To my surprise I found out that there were few columns which are renamed in SQL Server 2012 RC0. Usually when people see breaking changes they do not like it but when I see these changes I was happy as new names were meaningful and additionally their new conversion is much more practical and useful. Here are the columns previous names - Previous Column Name New Column Name physical_memory_in_bytes physical_memory_kb bpool_commit_target committed_target_kb bpool_visible visible_target_kb virtual_memory_in_bytes virtual_memory_kb bpool_commited committed_kb If you read it carefully you will notice that new columns now display few results in the KB whereas earlier result was in bytes. When I see the results in bytes I always get confused as I could not guess what exactly it will convert to. I like to see results in kb and I am glad that new columns are now displaying the results in the kb. I sent the details of the new columns to my friend and ask him to check the columns used in application. From my comment he quickly realized why he was facing error and fixed it immediately. Overall – all was well at the end and I learned something new. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL DMV, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology

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