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  • Service Oriented Architecture & Domain-Driven Design

    - by Michael
    I've always developed code in a SOA type of way. This year I've been trying to do more DDD but I keep getting the feeling that I'm not getting it. At work our systems are load balanced and designed not to have state. The architecture is: Website ===Physical Layer== Main Service ==Physical Layer== Server 1/Service 2/Service 3/Service 4 Only Server 1,Service 2,Service 3 and Service 4 can talk to the database and the Main Service calls the correct service based on products ordered. Every physical layer is load balanced too. Now when I develop a new service, I try to think DDD in that service even though it doesn't really feel like it fits. I use good DDD principles like entities, value types, repositories, aggregates, factories and etc. I've even tried using ORM's but they just don't seem like they fit in a stateless architecture. I know there are ways around it, for example use IStatelessSession instead of ISession with NHibernate. However, ORM just feel like they don't fit in a stateless architecture. I've noticed I really only use some of the concepts and patterns DDD has taught me but the overall architecture is still SOA. I am starting to think DDD doesn't fit in large systems but I do think some of the patterns and concepts do fit in large systems. Like I said, maybe I'm just not grasping DDD or maybe I'm over analyzing my designs? Maybe by using the patterns and concepts DDD has taught me I am using DDD? Not sure if there is really a question to this post but more of thoughts I've had when trying to figure out where DDD fits in overall systems and how scalable it truly is. The truth is, I don't think I really even know what DDD is?

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  • Printing HTML blocks

    - by Lem0n
    I have a page with a few tables that I want to be printable. I want the following behaviour: 1) Add a page break if the next table fits in a single page, but won't fit in the current page (because of other stuff already printed on this page) 2) Print the "table header" again in case it's needed to break a table (I guess it's the default behaviour) Any ideas specially on the first issue? Maybe some CSS can help? I'll give on example. I have a page with 4 tables. All of them with 10 lines, except the third one, with 50 lines. The first and second goes on the first page. Since the third one won't fit in the same page, but will fit in a page alone, it's printed on a page alone... and then the forth table is printed on the third page (in case it doesn't fit together in the second page). But, if the third page had 300 lines and would be broke anyway, it could have started to be print in the first page.

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  • A simple way to put a UIImage in a UIButton

    - by Alice
    I have a UIButton in my iPhone app. I set its size to 100x100. I have an image that is 400x200 that I wish to display in the button. The button STILL needs to stay at 100x100... and I want the image to downsize to fit... but keep the correct aspect ratio. I thought that's what "Aspect Fit" was used for. Do I include my image with setImage, or setBackgroundImage? Do I set AspectFit for the button? or the image? or the background image? (I need the smaller images to INCREASE in size. While larger images should DESCREASE in size. Always keeping the button at 100x100.) I've tried countless combinations of all of the above... and I just can't seem to get everything to work at the same time: Don't change the button's size of 100x100. Don't destroy the image's aspect ratio. Always increase small images to fit the button. Always decrease large images to fit the button. Never clip any of the image edges. Never require the "put UIButtons over all your UIimages" hack. Don't require everyone to upgrade to v4.2.1 just to use new framework methods. I see so many apps, with so many fully-working image-buttons... that I can't believe I can't figure out this very simple, very common thing. Ugh.

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  • Whats wrong with this video embed code?

    - by jamietelin
    Following embed code is from http://hd.se/landskrona/2010/04/09/kunglig-glans-pa-idrottsgalan/ but it doesn't work in Internet Explorer 8. Firefox no problems. Any recommendations for improvements? Thanks for your time! <object width="480px" height="294px" id="_36313041" data="http://hd.se/static/media/html/flash/video-3/flowplayer.swf" type="application/x-shockwave-flash"> <param name="movie" value="http://hd.se/static/media/html/flash/video-3/flowplayer.swf" /> <param name="allowfullscreen" value="true" /> <param name="allowscriptaccess" value="always" /> <param name="flashvars" value='config={"key":"$3fff7448b28a8cffc85","contextMenu":["hd.se videospelare 1.0"],"plugins":{"rtmp":{"url":"http://hd.se/static/media/html/flash/video-3/flowplayer.rtmp.swf"},"controls":{"height":24,"opacity":1,"all":false,"play":true,"time":true,"scrubber":true,"playlist":false,"mute":true,"volume":true,"fullscreen":true,"backgroundColor":"#222222","backgroundGradient":"none","buttonColor":"#7c7c7c","buttonOverColor":"#36558b","progressColor":"#7c7c7c","bufferColor":"#7c7c7c","timeColor":"#ffffff","durationColor":"#ffffff","timeBgColor":"#222222","scrubberHeightRatio":0.5,"scrubberBarHeightRatio":0.5,"volumeSliderHeightRatio":0.5,"volumeBarHeightRatio":0.5,"autoHide":"fullscreen","hideDelay":1800,"tooltips":{"buttons":true,"play":"Spela","pause":"Paus","next":"Nästa","previous":"Föregående","mute":"Ljud av","unmute":"Ljud på","fullscreen":"Fullskärmsläge","fullscreenExit":"Lämna fullskärmsläge"},"tooltipColor":"#153872","tooltipTextColor":"#ffffff"},"contentIntro":{"url":"http://hd.se/static/media/html/flash/video-3/flowplayer.content.swf","top":0,"width":736,"border":"none","backgroundColor":"#202020","backgroundGradient":"none","borderRadius":"none","opacity":"85pct","display":"none","closeButton":true}},"canvas":{"backgroundColor":"#000000","backgroundGradient":"none"},"play":{"replayLabel":"Spela igen"},"screen":{"bottom":24},"clip":{"scaling":"fit","autoPlay":true},"playlist":[{"provider":"rtmp","netConnectionUrl":"rtmp://fl0.c06062.cdn.qbrick.com/06062","url":"ncode/hdstart","autoPlay":false,"scaling":"fit"},{"url":"http://hd.se/multimedia/archive/00425/_kunligglans_HD_VP6_425359a.flv","scaling":"fit","autoPlay":true},{"provider":"rtmp","netConnectionUrl":"rtmp://fl0.c06062.cdn.qbrick.com/06062","url":"ncode/hdstopp","autoPlay":true,"scaling":"fit"}]}' /> </object>

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  • Rotate a table in word

    - by Jake Pearson
    I have a word 2007 document in portrait mode. I have a table that is too wide to fit in 8.5" but would fit in 11". Is there a way to make just one page landscape? Or alternately is there a way to rotate a table 90 degrees?

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  • How to disable check of free disk space before copying files?

    - by tputkonen
    I really hate the feature in Windows 7, that it verifies before copying any files whether the files fit to the destination drive. I have a pretty old MP3 player and I want to just select n songs and drag & drop them to the player, and copy as many files of the selection as possible. Windows 7 refuses to copy any of the files if all of them don't fit to the destination drive. How can I disable this annoying behaviour?

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  • Gridpanel auto resize on window resize

    - by imnotneo
    I'm using the array-grid extjs example to try and fit a gridpanel into a container window. The problem is on resizing the container window, the gridpanel doesn't automatically fit the new size. As I understand it that's how it's supposed to work. Here's the link to the example: http://www.extjs.com/deploy/dev/examples/grid/array-grid.html What I've done is changed the following.. // Added to gridpanel config layout: 'fit', viewConfig: { forceFit: true } // Window container var gridWindow = new Ext.Window({ items: [ grid ] }); // Instead of grid.render, use gridWindow.show(); gridWindow.show();

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  • Why Does .Hide()ing and .Show()ing Panels in wxPython Result in the Sizer Changing the Layout?

    - by MetaHyperBolic
    As referenced in my previous question, I am trying to make something slightly wizard-like in function. I have settled on a single frame with a sizer added to it. I build panels for each of the screens I would like users to see, add them to the frame's sizer, then switch between panels by .Hide()ing one panel, then calling a custom .ShowYourself() on the next panel. Obviously, I would like the buttons to remain in the same place as the user progresses through the process. I have linked together two panels in an infinite loop by their "Back" and "Next" buttons so you can see what is going on. The first panel looks great; tom10's code worked on that level, as it eschewed my initial, over-fancy attempt with borders flying every which way. And then the second panel seems to have shrunk down to the bare minimum. As we return to the first panel, the shrinkage has occurred here as well. Why does it look fine on the first panel, but not after I return there? Why is calling .Fit() necessary if I do not want a 10 pixel by 10 pixel wad of grey? And if it is necessary, why does .Fit() give inconsistent results? This infinite loop seems to characterize my experience with this: I fix the layout on a panel, only to find that switching ruins the layout for other panels. I fix that problem, by using sizer_h.Add(self.panel1, 0) instead of sizer_h.Add(self.panel1, 1, wx.EXPAND), and now my layouts are off again. So far, my "solution" is to add a mastersizer.SetMinSize((475, 592)) to each panel's master sizer (commented out in the code below). This is a cruddy solution because 1) I have had to find the numbers that work by trial and error (-5 pixels for the width, -28 pixels for the height). 2) I don't understand why the underlying issue still happens. What's the correct, non-ugly solution? Instead of adding all of the panels to the frame's sizer at once, should switching panels involve .Detach()ing that panel from the frame's sizer and then .Add()ing the next panel to the frame's sizer? Is there a .JustMakeThisFillThePanel() method hiding somewhere I have missed in both the wxWidgets and the wxPython documents online? I'm obviously missing something in my mental model of layout. Here's a TinyURL link, if I can't manage to embed the . Minimalist code pasted below. import wx import sys class My_App(wx.App): def OnInit(self): self.frame = My_Frame(None) self.frame.Show() self.SetTopWindow(self.frame) return True def OnExit(self): print 'Dying ...' class My_Frame(wx.Frame): def __init__(self, image, parent=None,id=-1, title='Generic Title', pos=wx.DefaultPosition, style=wx.CAPTION | wx.STAY_ON_TOP): size = (480, 620) wx.Frame.__init__(self, parent, id, 'Program Title', pos, size, style) sizer_h = wx.BoxSizer(wx.HORIZONTAL) self.panel0 = User_Interaction0(self) sizer_h.Add(self.panel0, 1, wx.EXPAND) self.panel1 = User_Interaction1(self) sizer_h.Add(self.panel1, 1, wx.EXPAND) self.SetSizer(sizer_h) self.panel0.ShowYourself() def ShutDown(self): self.Destroy() class User_Interaction0(wx.Panel): def __init__(self, parent, id=-1): wx.Panel.__init__(self, parent, id) # master sizer for the whole panel mastersizer = wx.BoxSizer(wx.VERTICAL) #mastersizer.SetMinSize((475, 592)) mastersizer.AddSpacer(15) # build the top row txtHeader = wx.StaticText(self, -1, 'Welcome to This Boring\nProgram', (0, 0)) font = wx.Font(16, wx.DEFAULT, wx.NORMAL, wx.BOLD) txtHeader.SetFont(font) txtOutOf = wx.StaticText(self, -1, '1 out of 7', (0, 0)) rowtopsizer = wx.BoxSizer(wx.HORIZONTAL) rowtopsizer.Add(txtHeader, 3, wx.ALIGN_LEFT) rowtopsizer.Add((0,0), 1) rowtopsizer.Add(txtOutOf, 0, wx.ALIGN_RIGHT) mastersizer.Add(rowtopsizer, 0, flag=wx.EXPAND | wx.LEFT | wx.RIGHT, border=15) # build the middle row text = 'PANEL 0\n\n' text = text + 'This could be a giant blob of explanatory text.\n' txtBasic = wx.StaticText(self, -1, text) font = wx.Font(11, wx.DEFAULT, wx.NORMAL, wx.NORMAL) txtBasic.SetFont(font) mastersizer.Add(txtBasic, 1, flag=wx.EXPAND | wx.LEFT | wx.RIGHT, border=15) # build the bottom row btnBack = wx.Button(self, -1, 'Back') self.Bind(wx.EVT_BUTTON, self.OnBack, id=btnBack.GetId()) btnNext = wx.Button(self, -1, 'Next') self.Bind(wx.EVT_BUTTON, self.OnNext, id=btnNext.GetId()) btnCancelExit = wx.Button(self, -1, 'Cancel and Exit') self.Bind(wx.EVT_BUTTON, self.OnCancelAndExit, id=btnCancelExit.GetId()) rowbottomsizer = wx.BoxSizer(wx.HORIZONTAL) rowbottomsizer.Add(btnBack, 0, wx.ALIGN_LEFT) rowbottomsizer.AddSpacer(5) rowbottomsizer.Add(btnNext, 0) rowbottomsizer.AddSpacer(5) rowbottomsizer.AddStretchSpacer(1) rowbottomsizer.Add(btnCancelExit, 0, wx.ALIGN_RIGHT) mastersizer.Add(rowbottomsizer, flag=wx.EXPAND | wx.LEFT | wx.RIGHT, border=15) # finish master sizer mastersizer.AddSpacer(15) self.SetSizer(mastersizer) self.Raise() self.SetPosition((0,0)) self.Fit() self.Hide() def ShowYourself(self): self.Raise() self.SetPosition((0,0)) self.Fit() self.Show() def OnBack(self, event): self.Hide() self.GetParent().panel1.ShowYourself() def OnNext(self, event): self.Hide() self.GetParent().panel1.ShowYourself() def OnCancelAndExit(self, event): self.GetParent().ShutDown() class User_Interaction1(wx.Panel): def __init__(self, parent, id=-1): wx.Panel.__init__(self, parent, id) # master sizer for the whole panel mastersizer = wx.BoxSizer(wx.VERTICAL) #mastersizer.SetMinSize((475, 592)) mastersizer.AddSpacer(15) # build the top row txtHeader = wx.StaticText(self, -1, 'Read about This Boring\nProgram', (0, 0)) font = wx.Font(16, wx.DEFAULT, wx.NORMAL, wx.BOLD) txtHeader.SetFont(font) txtOutOf = wx.StaticText(self, -1, '2 out of 7', (0, 0)) rowtopsizer = wx.BoxSizer(wx.HORIZONTAL) rowtopsizer.Add(txtHeader, 3, wx.ALIGN_LEFT) rowtopsizer.Add((0,0), 1) rowtopsizer.Add(txtOutOf, 0, wx.ALIGN_RIGHT) mastersizer.Add(rowtopsizer, 0, flag=wx.EXPAND | wx.LEFT | wx.RIGHT, border=15) # build the middle row text = 'PANEL 1\n\n' text = text + 'This could be a giant blob of boring text.\n' txtBasic = wx.StaticText(self, -1, text) font = wx.Font(11, wx.DEFAULT, wx.NORMAL, wx.NORMAL) txtBasic.SetFont(font) mastersizer.Add(txtBasic, 1, flag=wx.EXPAND | wx.LEFT | wx.RIGHT, border=15) # build the bottom row btnBack = wx.Button(self, -1, 'Back') self.Bind(wx.EVT_BUTTON, self.OnBack, id=btnBack.GetId()) btnNext = wx.Button(self, -1, 'Next') self.Bind(wx.EVT_BUTTON, self.OnNext, id=btnNext.GetId()) btnCancelExit = wx.Button(self, -1, 'Cancel and Exit') self.Bind(wx.EVT_BUTTON, self.OnCancelAndExit, id=btnCancelExit.GetId()) rowbottomsizer = wx.BoxSizer(wx.HORIZONTAL) rowbottomsizer.Add(btnBack, 0, wx.ALIGN_LEFT) rowbottomsizer.AddSpacer(5) rowbottomsizer.Add(btnNext, 0) rowbottomsizer.AddSpacer(5) rowbottomsizer.AddStretchSpacer(1) rowbottomsizer.Add(btnCancelExit, 0, wx.ALIGN_RIGHT) mastersizer.Add(rowbottomsizer, flag=wx.EXPAND | wx.LEFT | wx.RIGHT, border=15) # finish master sizer mastersizer.AddSpacer(15) self.SetSizer(mastersizer) self.Raise() self.SetPosition((0,0)) self.Fit() self.Hide() def ShowYourself(self): self.Raise() self.SetPosition((0,0)) self.Fit() self.Show() def OnBack(self, event): self.Hide() self.GetParent().panel0.ShowYourself() def OnNext(self, event): self.Hide() self.GetParent().panel0.ShowYourself() def OnCancelAndExit(self, event): self.GetParent().ShutDown() def main(): app = My_App(redirect = False) app.MainLoop() if __name__ == '__main__': main()

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  • WPF layout with several fixed height parts and certain parts relative to window size

    - by Daniil Harik
    Hello, At moment my main layout consists of vertically oriented stack panel and it looks like this: Root StackPanel StackPanel - fixed Height 150 (horizontal orientation) StackPanel - relative Height must be behalf of free space left on screen (but at least 150 px). Used by Telerik GridView Control, if I don't specify Height or MaxHeight Telerik GridView Height becomes very large and does not fit my window. StackPanel - fixed Height 100 (horizontal orientation) StackPanel - relative Height must be half of free space left on screen (but at least 150 px). Used by Telerik GridView Control, if I don't specify Height or MaxHeight Telerik GridView Height becomes very large and does not fit my window. StackPanel - fixed Height 100 (horizontal orientation) The view must totally fit available screen size. The problem is that I don't understand how to make certain areas of my view resize depending on available screen size. Is there is easy way to solve it, or should I be binding to Window height property and doing math? Thank You very much!

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  • hadoop beginners question

    - by Omnipresent
    I've read some documentation about hadoop and seen the impressive results. I get the bigger picture but am finding it hard whether it would fit our setup. Question isnt programming related but I'm eager to get opinion of people who currently work with hadoop and how it would fit our setup: We use Oracle for backend Java (Struts2/Servlets/iBatis) for frontend Nightly we get data which needs to be summarized. this runs as a batch process (takes 5 hours) We are looking for a way to cut those 5 hours to a shorter time. Where would hadoop fit into this picture? Can we still continue to use Oracle even after hadoop?

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  • Find longest initial substring which renders in a limited width

    - by Lu Lu
    Hello everyone, I have a long string, ex: "Please help me to solve this problem." This string is so long to fit in a width of 100 pixels. I need to get a substring of this string and substring will fit in 100 pixels. Ex: substring "Please help me to sol" is fit in 100 pixels. Please help me how to estimate a substring like this. Thanks. My application is Win Forms and C#.

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  • Get a substring of a long string which fits in a width

    - by Lu Lu
    Hello everyone, I have a long string, ex: "Please help me to solve this problem." This string is so long to fit in a width of 100 pixels. I need to get a substring of this string and substring will fit in 100 pixels. Ex: substring "Please help me to sol" is fit in 100 pixels. Please help me how to estimate a substring like this. Thanks. My application is Win Forms and C#.

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  • Error in glmmadmb(.....) The function maximizer failed (couldn't find STD file)

    - by Joe King
    This works fine: fit.mc1 <-MCMCglmm(bull~1,random=~school,data=dt1,family="categorical", prior=list(R=list(V=1, fix=1), G=list(G1=list(V=1, nu=0))), slice=T) So does this: fit.glmer <- glmer(bull~(1|school),data=dt1,family=binomial) But now I am trying to work with the package glmmadmb and this does not work: fit.mc12 <- glmmadmb(bull~1+(1|school), data=dt1, family="binomial", mcmc=TRUE, mcmc.opts=mcmcControl(mcmc=50000)) It generates the error: Error in glmmadmb(bull~ 1 + (1 | school), data = dt1, family = "binomial", : The function maximizer failed (couldn't find STD file) In addition: Warning message: running command '<snip>\cmd.exe <snip>\glmmadmb.exe" -maxfn 500 -maxph 5 -noinit -shess -mcmc 5000 -mcsave 5 -mcmult 1' had status 1

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  • Silverlight4 Printing Question

    - by hallgato.attila
    Hello everyone! I'm having a problem with printing. Is it possible to print a (customized) DataGrid which doesn't fit the page? a) Using a ViewBox to make it fit one page. My problem here is that I can get the PrintableArea.Width and PrintableArea.Height in the PrintPage EventHandler, from the PrintPageEventArgs, but in that Event Handler I can't set the size of an UIElement before it gets printed. b) Multiple pages. Is it possible somehow to print the whole DataGrid, even the parts which are not visible (don't fit the page) and to somehow make the PrintableArea only a part of the DataGrid?

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  • Where to split a string literal

    - by quinmars
    Every time I have to split a long string literal into two (or more) pieces, because it does not fit into a single line, I have to decide if I split the text before or after a space. For example: const char * long_text1 = "This is a long text, which does not fit " "in one line"; /* or */ const char * long_text2 = "This is a long text, which does not fit" " in one line"; I tend to use the first way, but I do not have a real reason for it. So I wonder is there any advantage to favor one of them? I know this questions tend to be coding style question, but that's not my intend. I only want to know if there is a convincing reason why one of those two ways might be preferable.

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  • "Zoom" text to be as big as possible within constraints/box

    - by stolsvik
    First problem: You have 400 pixels width to go on, and need to fit some text within that constraint as large as possible (thus, the text shall use that amount of space). Throw in a new constraint: If the text is just "A", then it shall not zoom this above 100 pixels (or some specific font size). Then, a final situation: Linebreaks. Fit some text in the largest possible way within e.g. 400 x 150 pixels. An obvious way is to simply start with point 1, and then increase until you can't fit it anymore. This would work for all three problems, but would be very crude. The fitting of a single line within bounds could be done by writing it with some fixed point size, check the resulting pixel bounds of the text, and then simply scale it with a transform (the text scales properly too then, check out TransformUI). Any ideas of other ways to attack this would be greatly appreciated!

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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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  • Diagram of Geek Culture (Geek Map) [Infographic]

    - by Asian Angel
    Want to have a fun look at geek culture and see just where you fit in? Then you need to see the Diagram of Geek Culture infographic that illustrator Julianna Brion has created. The infographic/map covers areas such as geek types, activities, obsessions, and more! Which part of geek culture do you fit into? Let us know in the comments! Geek Map [via Geeks are Sexy] View the Full-Size Version What is a Histogram, and How Can I Use it to Improve My Photos?How To Easily Access Your Home Network From Anywhere With DDNSHow To Recover After Your Email Password Is Compromised

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  • GDC 2012: DXT is NOT ENOUGH! Advanced texture compression for games

    GDC 2012: DXT is NOT ENOUGH! Advanced texture compression for games (Pre-recorded GDC content) Tired of fighting to fit your textures on disk? Too many bad reviews on long download times? Fix it! Don't settle for putting your raw DXT files in a ZIP, instead, compress your DXT textures by an extra 50%-70%! This talk will cover various ways to increase the compression of your game textures to allow for smaller distributables without introducing error, and allowing for fast on-demand decompression at run time. We'll cover how to losslessly squeeze your data with Huffman, block expansion, vector quantization, and we'll even take a look at what MegaTexture is doing too. If you've ever fought to fit textures into memory, this is the talk for you. Speaker: Colt McAnlis From: GoogleDevelopers Views: 1132 21 ratings Time: 33:05 More in Science & Technology

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  • What are the benefits and drawback of documentation vs tutorials vs video tutorials [closed]

    - by Cat
    Which types of learning resources do you find the most helpful, for which kinds of learning and/or perhaps at specific times? Some examples of types of learning you could consider: When starting to integrate a new SDK inside an existing codebase When learning a new framework without having to integrate legacy code When digging deeper into an already-used SDK that you may not know very well yet For example - (video) tutorials are usually very easy to follow and tells a story from beginning to end to get results, but will nearly always assume starting from scratch or a previous tutorial. Therefore such a resource is useful for quick learning if you don't have legacy code around, but less so if you have to search for the best-fit to the code you already have. SDK Documentation on the other hand is well-structured but does not tell a story. It is more difficult to get to a specific larger result with documentation alone, but it is a better fit when you do have legacy code around and are searching for perhaps non-obvious ways of employing the SDK or library. Are there other forms of resources that you find useful, such as interactive training?

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  • How can I find a good open source project to join?

    - by Lord Torgamus
    I just started working a year ago, and I want to join an open source project for the same reasons as anyone else: help create something useful and develop my skills further. My problem is, I don't know how to find a project where I'll fit in. How can I find a beginner-friendly project? What attributes should I be searching for? What are warning signs that a project might not be the right fit? Are there any tools out there to help match people with open source projects? There's a similar question here, but that question has to do with employment and is limited to PHP/Drupal.

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  • Why should we use low level languages if a high level one like python can do almost everything? [closed]

    - by killown
    I know python is not suitable for things like microcontrolers, make drivers etc, but besides that, you can do everything using python, companys get stuck with speed optimizations for real hard time system but does forget other factors which one you can just upgrade your hardware for speed proposes in order to get your python program fit in it, if you think how much cust can the company have to maintain a system written in C, the comparison is like that: for example: 10 programmers to mantain a system written in c and just one programmer to mantain a system written in python, with python you can buy some better hardware to fit your python program, I think that low level languages tend to get more cost, since programmers aren't so cheaply than a hardware upgrade, then, this is my point, why should a system be written in c instead of python?

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  • Looking for a simple to use email server that can be programmatically (preferably remotely) used

    - by sr2222
    I've been poking around the internet for much of the day, but I can't seem to find a good server to fit my needs. What I need is a simple to use and deploy (pref open source) lightweight email server that I can create users on programmaticly that has IMAP or POP support. I'd prefer something with an existing service interface, but if I have to write a REST API on top of an easy to use API, that's acceptable. The purpose of this tool will be to allow a test automation framework to create new email accounts and retrieve email sent to those addresses. I need text, html, and possibly attachment support as well. Perhaps it's my noobishness, but I can't really suss out the details from the documentation on the servers available out there to figure out which fit my needs.

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