Dark color schemes with ILPanel

I recently got a request for help in building an application, where ILPanel was supposed to create some plots with a dark background area. Dark color schemes are very popular in some industrial domains and ILNumerics’ ILPanel gives the full flexibility for supporting dark colors. Here comes a simple example:

And here comes the code used to create this example:

private void ilPanel1_Load(object sender, EventArgs e) {
    // create some test data
    ILArray<float> A = ILSpecialData.torus(1.3f, 0.6f);

    // create the plot: a simple surface
    ilPanel1.Scene.Add(new ILPlotCube(twoDMode: false) {
        new ILSurface(A, colormap: Colormaps.Summer) {
            // we also want a colorbar
            new ILColorbar() {
                Background = {
                    Color = Color.DarkGray

    // set the backcolor of the scene to black
    ilPanel1.BackColor = Color.Black; 

    // set labels color
    foreach (var label in ilPanel1.Scene.Find<ILLabel>()) {
        label.Color = Color.White;
        label.Fringe.Width = 0;

    // set the color of the default labels for axis ticks
    foreach (var axis in ilPanel1.Scene.Find<ILAxis>()) {
        axis.Ticks.DefaultLabel.Color = Color.White;
        axis.Ticks.DefaultLabel.Fringe.Width = 0;

    // some more configuration: the view limits
        new Vector3(0, 0, 1), new Vector3(2, 2, -1));


In line 4 we use the ILSpecialData class to create some test data. torus() creates the X, Y and Z values which eventually assemble a torus when used in ILSurface. The next line creates and adds a new plot cube to the scene. We set its two2Mode property to false, so we can rotate the torus with the mouse.

The next line creates a new surface and provides the torus data to it. As colormap ‘Colormaps.Summer’ is configured. Most surfaces need a colorbar in order to help mapping colors to actual values. We add a new colorbar below the surface and set its background color to some dark value.

Next, the BackColor of the main panel is set to black. Note, that setting the background color of a panel must be done in code in the current version (3.3.3). This is due to a bug in ILPanel which causes settings made in the designer to be ignored!

Now we have a dark background color but the labels still remain black. So let’s fix this: all labels which are part of the regular scene graph can easily be set at once. We simply use the ILGroup.Find() function to enumerate all labels and set their color to white. Also, we remove the fringe around them. Alternatively we could have set the fringe color to some dark color.

The last issue remaining is caused by the fact that labels for ticks cannot be configured here. The reason is, that tick labels are created dynamically. they don’t even exist at the time of execution of this code. So we must configure a thing called ‘DefaultLabel‘ instead. DefaultLabel is a member of the ticks collection of every axis object and used at runtime to provide default properties for all tick labels in auto mode.

This gives a nice dark color scheme. Keep in mind that the default color values for all scene-/plot objects are currently optimized for light background colors. Using dark backgrounds, therefore requires one to adjust the color on all plot objects accordingly.

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Large Object Heap Compaction – on Demand ??

In the 4.5.1 side-by-side update of the .NET framework a new feature has been introduced, which will really remove one annoyance for us: Edit & Continue for 64 bit debugging targets. That is really a nice one! Thanks a million, dear fellows in “the corp”!

Another useful one: One can now investigate the return value of functions during a debug session.

Now, while both features will certainly help to create better applications by helping you to get through your debug session more quickly and conveniently, another feature was introduced, which deserves a more critical look: now, there exist an option to explicitly compact the large object heap (LOH) during garbage collections. MSDN says:

If you assign the property a value of GCLargeObjectHeapCompactionMode.CompactOnce, the LOH is compacted during the next full blocking garbage collection, and the property value is reset to GCLargeObjectHeapCompactionMode.Default.

Hm… They state further:

You can compact the LOH immediately by using code like the following:

GCSettings.LargeObjectHeapCompactionMode = GCLargeObjectHeapCompactionMode.CompactOnce;

Ok. Now, it looks like there has been quite some demand for ‘a’ solution for a serious problem: LOH fragmentation. This basically happens all the time when large objects are created within your applications and relased and created again and released… you get the point: disadvantageous allocation pattern with ‘large’ objects will almost certainly lead to holes in the heap due to reclaimed objects, which are no longer there, but other objects still resisting in the corresponding chunk, so the chunk is not given back to the memory manager and OutOfMemoryExceptions are thrown rather early …

If all this sounds new and confusing to you – no wonder! This is probably, because you are using ILNumerics :) Its memory management prevents you reliably from having to deal with these issues. How? Heap fragmentation is caused by garbage. And the best way to handle garbage is to prevent from it, right? This is especially true for large objects and the .NET framework. And how would one prevent from garbage? By reusing your plastic bags until they start disintegrating and your eggs get in danger of falling through (and switching to a solid basket afterwards, I guess).

In terms of computers this means: reuse your memory instead of throwing it away! Especially for large objects this puts way too much pressure on the garbage collector and at the end it doesn’t even help, because there is still fragmentation going on on the heap. For ‘reusing’ we must save the memory (i.e. large arrays in our case) somewhere. This directly leads to a pooling strategy: once an ILArray is not used anymore – its storage is kept safe in a pool and used for the next ILArray.

That way, no fragmentation occurs! And just as in real life – keeping the environment clean gives you even more advantages. It helps the caches by presenting recently used memory and it protects the application from having to waste half the execution time in the GC. Luckily, the whole pooling in ILNumerics works completely transparent in the back. There is nothing one needs to do in order to gain all advantages, except following the simple rules of writing ILNumerics functions. ILNumerics keeps track of the lifetime of the arrays, safes their underlying System.Arrays in the ILNumerics memory pool, and finds and returns any suitable array for the next computation from here.

The pool is smart enough to learn what ‘suitable’ means: if no array is available with the exact length as requested, a next larger array will do just as well:

public ILRetArray CreateSymm(int m, int n) {
    using (ILScope.Enter()) {
        ILArray A = rand(m,n);
        // some very complicated stuff here...
        A = A * A + 2.3;
        return multiply(A,A.T);

// use this function without worrying about your heap!
while (true) {
   dosomethingWithABigMatrix(CreateSymm(1000,2000)); // one can even vary the sizes here!
   // at this point, your heap is clean ! No fragmentation! No GC gen.2 collections !

Keep in mind, the next time you encounter an unexpected OutOfMemoryException, you can either go out and try to make use of that obscure GCSettings.LargeObjectHeapCompactionMode property, or … simply start using ILNumerics and forget about that problem at least.

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ILNumerics Language Features: Limitations for C#, Part II: Compound operators and ILArray

A while ago I blogged about why the CSharp var keyword cannot be used with local ILNumerics arrays (ILArray<T>, ILCell, ILLogical). This post is about the other one of the two main limitations on C# language features in ILNumerics: the use of compound operators in conjunction with ILArray<T>. In the online documentation we state the rule as follows:

The following features of the C# language are not compatible with the memory management of ILNumerics and its use is not supported:

  • The C# var keyword in conjunction with any ILNumerics array types, and
  • Any compound operator, like +=, -=, /=, *= a.s.o. Exactly spoken, these operators are not allowed in conjunction with the indexer on arrays. So A += 1; is allowed. A[0] += 1; is not!

Let’s take a closer look at the second rule. Most developers think of compound operators as being just syntactic sugar for some common expressions:

int i = 1;
i += 2;

… would simply expand to:

int i = 1;
i  = i + 2; 

For such simple types like an integer variable the actual effect will be indistinguishable from that expectation. However, compound operators introduce a lot more than that. Back in his times at Microsoft, Eric Lippert blogged about those subtleties. The article is worth reading for a deep understanding of all side effects. In the following, we will focus on the single fact, which becomes important in conjunction with ILNumerics arrays: when used with a compound operator, i in the example above is only evaluated once! In difference to that, in i = i + 2, i is evaluated twice.

Evaluating an int does not cause any side effects. However, if used on more complex types, the evaluation may does cause side effects. An expression like the following:

ILArray<double> A = 1;
A += 2;

… evaluates to something similiar to this:

ILArray<double> A = 1;
A = (ILArray<double>)(A + 2); 

There is nothing wrong with that! A += 2 will work as expected. Problems arise, if we include indexers on A:

ILArray<double> A = ILMath.rand(1,10);
A[0] += 2;
// this transforms to something similar to the following:
var receiver = A;
var index = (ILRetArray<double>)0;
receiver[index] = receiver[index] + 2; 

In order to understand what exactly is going on here, we need to take a look at the definition of indexers on ILArray:

public ILRetArray<ElementType> this[params ILBaseArray[] range] { ... 

The indexer expects a variable length array of ILBaseArray. This gives most flexibility for defining subarrays in ILNumerics. Indexers allow not only scalars of builtin system types as in our example, but arbitrary ILArray and string definitions. In the expression A[0], 0 is implicitly converted to a scalar ILNumerics array before the indexer is invoked. Thus, a temporary array is created as argument. Keep in mind, due to the memory management of ILNumerics, all such implicitly created temporary arrays are immediately disposed off after the first use.

Since both, the indexing expression 0 and the object where the indexer is defined for (i.e.: A) are evaluated only once, we run into a problem: index is needed twice. At first, it is used to acquire the subarray at receiver[index]. The indexer get { ...} function is used for that. Once it returns, all input arguments are disposed – an important foundation of ILNumerics memory efficency! Therefore, if we invoke the index setter function with the same index variable, it will find the array being disposed already – and throws an exception.

It would certainly be possible to circumvent that behavior by converting scalar system types to ILArray instead of ILRetArray:

ILArray A = ...;
A[(ILArray)0] += 2;

However, the much less expressive syntax aside, this would not solve our problem in general either. The reason lies in the flexibility required for the indexer arguments. The user must manually ensure, all arguments in the indexer argument list are of some non-volatile array type. Casting to ILArray<T> might be an option in some situations. However, in general, compound operators require much more attention due to the efficient memory management in ILNumerics. We considered the risk of failing to provide only non-volatile arguments too high. So we decided not to support compound operators at all.

See: General Rules for ILNumerics, Function Rules, Subarrays

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Troubleshooting: Adding Controls to the VS Toolbox

Since we’re offering NuGet packages, adding ILNumerics to Visual Studio has become a quite convenient task: It’s easy to use the ILNumerics math library for own projects in .NET. However, from time to time users have problems adding the ILNumerics controls to their Visual Toolbox Window.

That’s what a post on Stack Overflow from earlier this year was about: A developer who wanted to use our C# math library for 3d visualizations and simulations wasn’t able to access the ILNumerics controls. “How can I locate those?”, he was wondering. “Do I have to make some changes to my VS?”

Adding ILNumerics Controls to the Visual Studio Toolbox manually

If the ILNumerics math library is installed to a project, normally the ILNumerics controls are automatically listed in the Visual Studio toolbox. However, if that’s not the case there’s a way to a add them manually: After clicking right onto the toolbox, you can select “Choose Item”. The dialog allows you to select the assambly to load the controls from – that’s it! If you’re using NuGet, the .dll can be found in your project folder, “packages/ILNumericsX.X.X/lib”.

However, if that doesn’t work straightaway, it often helps to clear the toolbox from any copies of custom controls before – simply right-click it and choose “Reset Toolbox”.

Need help? ILNumerics Documentation and Support

You want to know more about our math library and its installation? Check out our documentation and the Quick Start Guide! If you have any technical questions, have a look at our Support Section.

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Using LAPACK in C#/.NET: Linear Equotation Systems in ILNumerics

If you install a math library to your .NET/C# project, LAPACK will be probably one of the key feature you expect from that: The routines provided by LAPACK (which actually means: “Linear Algebra Package”) cover a wide range of functionalities needed for nearly any numerical algorithm, in natural sciences, computer science, and social science.

The LAPACK software library is written in FORTRAN code – until 2008 it was even written in FORTRAN 77. That’s why adding LAPACK functions to an enterprise software project written in Java or C#/.NET can be quite a demanding task: The implementation of native modules often causes problems regarding maintainability and steadiness of enterprise applications.

Our LAPACK implementation for C#/.NET

ILNumerics offers a convenient implementation of LAPACK for C# and .NET: It provides software developers both the execution speed of highly optimized processor specific native code and the convenience of managed software frameworks. That allows our users to create powerful applications in a very short time.

For linear algebra functions ILNumerics uses the processor-optimized LAPACK library by the MIT and Intel’s MKL. ILMath.Lapack is a concrete interface wrapper class that provides the native LAPACK functions. The LAPACK wrapper is initialized when a call to any static method of ILMath is made. Once the corresponding binaries for your actual architecture have been found, consecutive calls will utilize them in a very efficient way.

The MKL is utilized (and needed) for all calls to any fft(A) function, for matrix decompositions (like for example linsolve, rank, svd, qr etc.). The only exception to that is ILMath.multiply – the general matrix multiplication. Matrix multiplication is just such an often needed feature, a math library simply could not go without. So we decided to implement ILMath.multiply() purely in managed code. The good thing: it is not really far behind the speed of the processor optimized version! If MKL binaries are found at runtime, those will be used, of course. But in the case of their absence, the managed version should work out just fast enough for the very most situations.

In most cases using this kind of .NET/C# LAPACK implementation means: faster results and more stable software applications. Learn more about Linear Equation Systems and other features of ILNumerics in our Documentation.

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C# for 3D visualizations and Plotting in .NET

2D and 3D Visualizations are an important feature for a wide range of domains: both software developers and scientists often need convenient visualization facilities to create interactive scenes and to make data visible. The ILNumerics math library brings powerful visualization features to C# and .NET: ILView, the ILNumerics Scene Graph API and its plotting engine. We’d like to give an overview over our latest achievements.

ILView: a simple way to create interactive 3d visualizations

We have created ILView as an extension to our interactive web component: It allows you to simply try out ILNumerics’ 2d and 3d visualization features by chosing the output format .exe in our visualization examples. But that’s not all: ILView is also a general REPL for the evaluation of computational expressions using C# language. ILView is Open Source – find it on GitHub!

Screenshot of ILView

Using ILView for interactive 3D Visualization

ILNumerics Scene Graph: realize complex visualizations in .NET

The ILNumeric’s scene graph is the core of ILNumerics’ visualization engine. No matter if you want to create complex interactive 3D visualizations, or if you aim at enhancing and re-configuring existing scenes in .NET: The ILNumerics scene graph offers a convenient way to realize stunning graphics with C#. It uses OpenGL, GDI, and it’s possible to export scenes into vector and pixel graphics.

Screenshot of an interactive 3D scene

Using C# for 3D visualizations: the ILNumerics Scene Graph

Scientific Plotting: visualize your data using C#

With ILNumerics’ visualization capabilities, C# becomes the language of choice for scientists, engineers and developers who need to visualize data: Our plotting API and different kinds of plotting types (contour plots, surface plots etc.) make easy work of creating beautiful scientific visualizations.

Screenshot of a Surface Plot in ILNumerics

Scientific Plotting in .NET: A Surface Plot created with ILNumerics

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Are you afraid of software developers?

In the 1980s and 1990s software developers had to face a bunch of bad prejudices: They were known to be sociophobic nerds, neglecting their real lifes in favor of hanging in front of the computer for writing code, discussing in hacking newsgroups and eating pizza.

Even though we’re still not living in a society of hackers, geekism has become mainstream. Not only the fact that most people spend a lot of time with their smartphones and computers: nerd culture is more popular than ever. Some weeks ago Luke Maciak wrote a nice article on that topic.

The establishment towards nerdism changed, and so did the general attitude towards software developers. In a way, programmers have become role models for the 21st century – not at least because they are an important factor regarding economic growth in the digital age.

However, having visited some events for start ups in Berlin has made us come across a new kind of prejudices towards developers. Most start ups in Berlin are more or less in the tech business: They create games, offer online services or develop facebook apps. Many of them have no CTOs in their teams, though. That’s why they employ freelancer developers.

Working together with software developers on this early stage of business is challanging for start ups. They often don’t have much money to spend: that’s why the wages developers ask for seem to be too high. Start ups want a strong team spirit: that’s why they don’t like developers to work from another place than their office.

But the most important problem is: As most founders aren’t developers theirselves, they don’t understand what their expensive freelancer is actually doing when he spends his days coding at home. For theis reason, young CEOs often become nervous: As their business depends on software, they feel like being on their developer’s mercy because he seems to be the only one who is actually able to understand his code.

In most cases we can calm down our fellows: Developers are used to get paid well and work when and where they want to. There’s also no reason to be afraid that no other developer would find his way into your software’s code: Modern languages and frameworks like .NET, Java or Ruby make most applications clean and well organized. So even in case you really have to split up with your developer, it won’t be that hard to find a new one who can continue his or her antecessor’s work.

In other words: In most cases there’s no need to be afraid of software developers. It’s pretty convenient to monitor enterprise software development these days.

However, the following question shows that this kind of convenience hasn’t arrived everywhere yet: “Why does scientific computing today still use only technology of the last century?”, someone claimed on reddit some days ago. This kind of question is the reason we have created ILNumerics: For the first time it brings the convenience and the improved efficiency and maintainence of modern managed languages to the development of numerical algorithms and 3d visualizations.

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Scientific Computing Online: IPython Notebook, Shiny (R) and ILNumerics

It seems that we’re facing a trend at the moment: scientific computing, math and visualization software for web browsers. With our interactive web examples we have taken a step into that direction, too: Visitors of our website can change the C# code of our plotting and visualization demos in order to create a new SVG, PNG, JPG or EXE output. This allows people to easily try out the ILNumerics syntax and our powerful 2d and 3d visualization features for .NET. In addition to that, ILView allows a convenient way to interactively explore scenes that are created with ILNumerics.

There are two other web applications that cause a lot of excitement in the scientific community at the moment: The IPython Notebook and Shiny, a tool for creating web applications in R. Let’s have a closer look…

IPython Notebook: “Interactive Computational Environment”

The IPython Notebook adresses the huge amount of Python users in the scientific community. It basically offers a new way for writing papers: It’s a web based editor for code execution, math, text and visualization. Because the IPython Notebook combines all parts you normally need to write a scientific paper, you won’t have to import / export different elements from several domain specific software applications: “Everything related to my analysis is located in one unified place”, explains Philip J. Guo in his blog (http://www.pgbovine.net/ipython-notebook-first-impressions.htm). Once you have finished your paper, you can share your IPython Notebook as HTML and PDF with your colleagues, your professor etc.

Shiny: “Easy web applications in R”

Shiny stands for a different approach: It allows you to implement own analysis into web applications. While IPython obviously adresses Python users, Shiny is based on R, a still very popular programming language among statisticians. What makes Shiny interesting are its interactivity features: Most demos on the Shiny website offer the opportunity to choose input parameters from text fields or drop-downs to dynamically change the output visualization. The code seems to be quite similar to R, so users who are familiar with that language will easily be able to create interactive data visualization applications for their websites using Shiny.

Disadvantages: Performance does matter

Both approaches make web browsers accesable for specific needs of scientific visualization: The IPython Notebook offers a convenient tool to share the results of analytics related research; Shiny allows R developers to publish particular interactive plots on the web.

However, both projects are limited – namely because of technological issues. The level of performance that can be realized with both platforms is restricted: You’ll face that at the latest when you start creating complex 3d scenes with either Python or R. This holds true for the platforms’ web applications, too…

Outlook: Scientific Computing online

For certain purposes web based scientific computing software offers new convenient solutions. But if you want to realize complex interactive 3d visualizations, you still won’t use any of them but an application on your local machine instead.

Our interactive web examples point the direction we want to go. In order to make scientific computing more powerful, we’re working on the next step of our approach: a full WebGL support for ILNumerics. Stay tuned…

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High Performance Fast Fourier Transformation in .NET

„I started using ILNumerics for the FFT routines. The quality and speed are excellent in a .NET environment.“

The Fourier Transform (named after French mathematician and physicist Joseph Fourier) allows scientists to transform signals between time domain and frequency domain. This way, an arbitrary periodic function can be expressed as a sum of cosine terms. Think of the equalizer of your mp3-player: It expresses your music’s signal in terms of the frequencies it is composed of.

The Fast Fourier Transform (FFT) is an algorithm for the rapid computation of discrete Fourier Transforms’ values. Being one of the most popular numerical algorithms, it is used in physics, engineering, math and many other domains.

In terms of software engineering, the Fast Fourier Transform is a very demanding algorithm: In the .NET-framework, a naive approach would cause very low execution speeds. That’s the reason why many .NET-developers have to implement native C-libraries when it comes to FFTs.

ILNumerics uses Intel’s® MKL for Fast Fourier Transforms: That’s why our users don’t have to implement native library’s themselves for high performance FFTs. No matter if they have a scientific or an industrial background, many developers rely on ILNumerics because of its implementation of the Fast Fourier Transform. It’s the fastest you can get today – even for big amounts of data.

ILNumerics provides interfaces to forward and backward Fourier Transformations, for real and complex floating point data, in single and double precision, in one, two or n dimensions. In addition to the MKL’s FFTs, prepared interfaces for FFTW and for AMDs ACML exist.

Learn more about the ILNumerics library and its implementation of Fast Fourier Transformation in C#/.NET in the online documentation!

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AnyCPU Computing, limping Platform Specific Targets and a Happy Deployment End

One issue escorted ILNumerics for just a long enough time. It is an issue which prevented ILNumerics to deploy to multiple platform targets seamlessly. It completely prevented designer support for visualization applications when targeting 64 bit. It prevented a developer from easily switching between 32 bit and 64 bit targets in Visual Studio for testing purposes. And it – no wonder – caused a whole bunch of confusion among our users and a correspondingly huge amount of support requests: native dependencies.

AnyCPU in the Wild

It’s been a sad story from the beginning. There is that great feature of .NET which they call ‘AnyCPU’ platform target. The idea is simple: one creates an application once and simply deploys it to any platform supporting .NET. Regardless, if the target computer runs on x86 or x64 or … ok, lets stop here for now ;) ! As simple as the idea is, as successfull it turns out to work in the wild. Platform specific differences between 32 and 64 bit environments are transparently abstracted away by the .NET languages (see: IntPtr) and the CLR. It is all good and fine … until native dependencies come into play.

As the name suggests, native dlls are not managed. They are compiled from pure unmanaged code. They do no abstraction work nor support such attempts by the CLR. Most of the time (at least regarding the ILNumerics native dependencies) they incorporate all the nifty pointer calculations which bring the last little quant of performance and all its danger that eventually leads us to move away from C/C++, right? Nevertheless, we sometimes still need those native libs – even though the number of such places are decreasing. All visualizations in ILNumerics run purely managed. From version 3.0 we have presented our own pure managed matrix multiplication. It works similar to the famous GOTO BLAS and handles even largest matrices in a very cache friendly way – very efficiently. It uses almost all tricks the MKL utilizes as well. And it beats all other managed implementations known to us by factors. However, it does not utilize AVX extensions (yet). Hence, is still keeps behind the MKL …

That’s where the Hassle starts

So we sometimes need native dependencies. What is the best way to incorporate them into your project without also incorporating all their disadvantages? We certainly do not want the whole application to be tied to a specific target platform just because it utilizes some routines from a native dll! We want ILNumerics to target ‘AnyCPU’ and let the final application and the machine it eventually runs on decide the bitrate. The problem with this approach is, that we need different native binaries for every platform. And even worse, the dependencies must be visible to the application at runtime.

A common deployment scheme for such native DLLs is to simply place them next to your application assembly in the same folder. According to the way a module is loaded by .NET (and Windows in general), it first looks for matching modules in the same folder where the application itself lays in. This simple scheme is sufficient for most cases – if the target platform is known in advance! However, when it comes to AnyCPU targets, this is not the case. We simply do not know if the application is to be run as 64 bit or as 32 bit process eventually.

Placing all dependencies for both 32 bit and 64 bit into the execution folder does obviously not improve the situation either. The Intel® MKL for example is compiled to arbitrary named DLLs. However, while the entry assembly can be given an individual name, differentiating between 32 and 64 bit, this is not true for dependencies of those dependencies. ‘libiomp5md.dll’ is needed by both. And it would require some serious dive into the MKL linking scheme to have individual mkl_custom.dll’s reference individually named dependencies. Hence, we cannot place all DLLs for all targets next to each other into the same folder. The former deploy scheme of ILNumerics (prior to version 3.2) used some naming scheme in order to solve those conflicts. But in the end, this did not really solve the issue but only helped preventing from accidentally mixing up files of different platforms – not without introducing new problems…

Introducing an old Pal: %PATH%

Several ‘official’ solutions are proposed for the problem:
1. Installations. The maintainer of the application (you) takes care of selecting correct binaries during installation time and installs the application for a specific target. Alternatively, on 64 bit systems, where applications have the option to run as both, 32 bit and 64 bit processes, native dependencies are placed (‘installed’) into corresponding system directories. All 64 bit dlls go into %SystemRoot%\system32 (not mistaken here) and all 32 bit DLLs go into %SystemRoot%\SysWoW64. Don’t blame me for the naming confusion. It is a good example for derived compatibility problems and actually makes sense – just not on the first sight.

If at runtime the assembly loader attempts to load a native dependency, it looks into these individual directories as well – into which one depends on the current bitrate of the process. Going that way, dependencies with similar names are nicely seperated and everything goes well. Obviously, administrative rights are necessary to store the DLLs into those system folders. And, unless one is really carefully, this may become the entry to the famous DLL hell…

2. AppDomain.AssemblyResolve. This is the .NET way of dealing with the issue. Unfortunately, it introduces a whole chain of other issues which are not obvious at first sight. But the biggest argument against it is the simplicity and beauty of the third option:

3. The environment path method. It has been internalized for a long time that modules are searched for in several directories, including those which are listed in the PATH environment variable. This offers an easy yet efficient way of dealing with native binaries for different platforms. All we have to do is to make sure that the native dependencies are seperated in individual (sub-)folders. At application or library startup the current bitrate of the process is examined and the PATH environment variable is altered accordingly to include the correct directory. Several variants exist to that approach. One of them is to preload the correct version of a dll from a subdirectory at startup and let the assembly loader cache handle repeated load attempts. However, due to its simplicity we stick to the PATH environment variable method. PATH can be altered even in a medium trust environment (which is important for our Web Code Component and ASP.NET in general). It needs some attention at startup once for the whole library but does not require special handling for individual dependencies afterwards.

Manually importing ILNumerics binaries into your project

Now let’s get our hands dirty! Here comes the new file scheme for deploying ILNumerics and its native dependencies. The whole setup is simplified dramatically by using the nuget packages, which is described at the end of this post. The following manual steps are only required, if you cannot or don’t want to use the nuget package manager for some reasons. One of those rare cases: if you want to use the source code distribution of the Community Edition (GPLv3) or want to setup ILNumerics without access to the official nuget repository.

The deploy package of the Professional Edition shows the following scheme:

/ - Root folder of the zip package
- bin
|- bin32 - 32 bit (Windows and Linux) native dependencies
|- bin64 - 64 bit (Windows) native dependencies
|- ILNumerics.dll - AnyCPU .NET merged assembly, used for all targets
|- ILNumerics.dll.config - Config file, needed for Linux plotting only
|- ILNumerics.dll.xml - Intellisense support file for Visual Studio
- doc - documentation folder, changelog and offline documentation
- ... (other files not considered here)

Other editions have a similar file structure. The important parts: There are two binary folders ‘bin32′ and ‘bin64′. Both include all native binaries necessary for each corresponding platform. These binaries contained for 32 bit and for 64 bit (may) have the same names but are strictly seperated into individual folders.

If you are targeting a single platform only (let’s say: x86) you might reuse the old deployment scheme: take the binaries from the bin32 folder and make sure they are found at runtime by ILNumerics.dll. So one might choose to simply place the binaries next to ILNumerics.dll. This old scheme will still work! However, in order to enable real multi-platform target support for both 32 and 64 bit, the following steps direct the solution:

Steps to incorporate ILNumerics as multi-platform target (AnyCPU) into your existing project:
1. Extract the whole distribution package into a directory on your harddisk.
2. Add a reference to ILNumerics.dll in the package as regular managed library reference for your project. Visual Studio copies the xml intellisense documentation and the corresponding .config file automatically.
3. Use Windows Explorer to copy both: bin32/ and bin64/ including all their content into the root folder of your new project. The root folder commonly is the one the *.csproj file lives in.
4. Back to Visual Studio, open the Solution Explorer and click on the ‘Show All Files’ icon. This will make all files from the directory visible – regardless if they are part of the VS project or not.
5. Find both folders (bin32 and bin64), right click and select: ‘Include In Project’.
6. Expand the content of both folders and select all DLLs contained. Press F4 to open the Property tool window.
7. Make sure to select ‘Copy to Output Directory’ -> ‘Copy If Newer’.

Your project is now setup to run with ILNumerics as AnyCPU target! You may try it out by simply switching the project target between x86, x64 (and AnyCPU if you like). In order to test if the native binaries are available at runtime, run the following snippet somewhere in your code:

ILNumerics.ILArray A = ILNumerics.ILMath.fft(ILNumerics.ILMath.rand(100,200));

FFT in ILNumerics (still) depends on the native MKL binaries. Hence, this code would fail if they would not be found at runtime. Make sure that all needed platform targets are working by switching the application targets in the Project Properties in Visual Studio and rerunning your application.

The Happy End – Recommended Way of Importing ILNumerics

Now it is certainly nice to have a setup with native binaries which runs on every platform target without ever having to exchange native dlls manually. However, the setup can be simplified further. NuGet comes in handy here. By utilizing the NuGet package manager the setup of ILNumerics for your project boils down to the follwing three simple steps:

1. Right Click on the project in the Visual Studio Solution Explorer. Select ‘Manage NuGet Packages’
2. Search for available packages by name: ‘ILNumerics’.
3. From the list of found packages, select ‘ILNumerics’ (not ‘ILNumerics32′ nor ‘ILNumerics64′ – these are deprecated now!) and install the ‘ILNumerics’ package.

If you are familiar with our older packages, you will notice that ILNumerics is now split into two individual packages: ILNumerics and ILNumerics.Native. Former basically consists out of the ILNumerics.dll (AnyCPU) only. It is a purely managed assembly, merged with several other .NET assemblies needed by the ILNumerics visualization part. This package does not include any native binaries. These come into play as dependency package ‘ILNumerics.Native’, referenced from the main ILNumerics package. It is automatically loaded when the main ILNumerics package is referenced.

NuGet does all the work described above in the manual setup for us: referencing the managed DLL, copying the bin32 and bin64 folder, including them into the project and making sure that the native binaries are deployed to your project output directory.

Note, the new AnyCPU target support is valid from version 3.2. It replaces the old (platform specific) deployment scheme immediately. This is a breaking change for all users, which have relied on the nuget packages ILNumerics.32Bit or ILNumerics.64Bit. Both old packages are deprecated now. We recommend switching to the new deployment scheme soon.

Download ILNumerics here! Please report back any problems you may find or any restrictions the new scheme may introduce for your setup. Thanks!

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