Integrating MatLab with C#

Hello,

I'm trying to learn how to integrate MatLab code with C# via .dll. I found the following example project and attempted to compile it: http://www.mathworks.com/matlabcentr...-matlab-with-c

The MatLab end of it worked fine, but I got the following error when I tried to compile it in Visual Studio. I've copied the example code first.

Code:

---

using System;
using System.Collections.Generic;
using System.Text;

// MathWorks assemblies that ship with Builder for .NET
// and should be registered in Global Assembly Cache
using MathWorks.MATLAB.NET.Utility;
using MathWorks.MATLAB.NET.Arrays;

// Assembly built by Builder for .NET containing
// math_on_numbers.m
using dotnet;

// To include the C Shared Library created with
// MATLAB Compiler we need to include InteropServices
// to integrate the unmanaged code
using System.Runtime.InteropServices;


// Copyright 2006, 2007, 2010 The MathWorks, Inc.

namespace example_ML_integration
{
    class Program
    {
        static void Main(string[] args)
        {
            //////////////////////
            // Runtime Parameters
            //////////////////////

            // Create a mode variable to determine which
            // method is used.
            // 1 = MATLAB Com engine interface
            // 2 = .NET Assembly
            // 3 = C shared library
            System.Int16 Mode = 2;

            ////////////////////
            // Input Parameters
            ////////////////////

            // create an array ar for the real part of "a"
            System.Array ar = new double[2];
            ar.SetValue(11, 0);
            ar.SetValue(12, 1);

            // create an array ai for the imaginary part of "a"
            System.Array ai = new double[2];
            ai.SetValue(1, 0);
            ai.SetValue(2, 1);

            // create an array br for the real part of "b"
            System.Array br = new double[2];
            br.SetValue(21, 0);
            br.SetValue(22, 1);

            // create an array bi for the imaginary part of "b"
            System.Array bi = new double[2];
            bi.SetValue(3, 0);
            bi.SetValue(4, 1);

            /////////////////////
            // Output Parameters
            /////////////////////

            // initialize variables for return value from ML
            System.Array cr = new double[2];
            System.Array ci = new double[2];
            System.Array dr = new double[2];
            System.Array di = new double[2];


            ////////////////////////
            // Call MATLAB function
            ////////////////////////
            // call appropriate function/method based on Mode
            if (Mode == 1)
            {
                // use MATLAB engine
                UseEngine(ar, ai, br, bi, ref cr, ref ci, ref dr, ref di);
            }
            else if (Mode == 2)
            {
                // use .NET assembly created with Builder for .NET
                UseDotNET(ar, ai, br, bi, ref cr, ref ci, ref dr, ref di); // ERROR IS IN THIS LINE
            }
            else if (Mode == 3)
            {
                // use C Shared Library created with MATLAB Compiler
                UseClib(ar, ai, br, bi, ref cr, ref ci, ref dr, ref di);
            }
            // any other value of Mode is invalid and we can do nothing


            /////////////////////
            // Output to console
            /////////////////////
            DisplayMethod(Mode);
            DisplayArgs( true, ar, ai, br, bi); // true = input
            DisplayArgs(false, cr, ci, dr, di); // false = not-input or output
            DisplayEnd();


        }

        /*
        * All input and output arguments must have been allocated
        * prior to calling these functions
        *
        *  Input:
        *      ar  real      part of a
        *      ai  imaginary part of a
        *      br  real      part of b
        *      bi  imaginary part of b
        *
        *  Output:
        *      cr  real      part of c
        *      ci  imaginary part of c
        *      dr  real      part of d
        *      di  imaginary part of d
        */
        static private void UseEngine(Array ar, Array ai, Array br,
            Array bi, ref Array cr, ref Array ci, ref Array dr, ref Array di)
        {
          /*
            * This function calls the math_by_numbers routine inside
            * MATLAB using the MATLAB Engine's com interface
            */
       
            // Instantiate MATLAB Engine Interface through com
            MLApp.MLAppClass matlab = new MLApp.MLAppClass();

            // Using Engine Interface, put the matrix "a" into
            // the base workspace.
            // "a" is a complex variable with a real part of ar,
            // and an imaginary part of ai
            matlab.PutFullMatrix("a", "base", ar, ai);

            // Using Engine Interface, put the matrix "b" into
            // the base workspace.
            // "b" is a complex variable with a real part of br,
            // and an imaginary part of bi
            matlab.PutFullMatrix("b", "base", br, bi);

            // Using Engine Interface, execute the ML command
            // contained in quotes.
            matlab.Execute("cd c:\\demos\\CSharp_MATLAB\\mcode;");
            matlab.Execute("open math_on_numbers.m");
            matlab.Execute("dbstop in math_on_numbers.m");
            matlab.Execute("[c, d] = math_on_numbers(a,b);");
            matlab.Execute("com.mathworks.mlservices.MLEditorServices.closeAll");
            //matlab.Execute("dbquit all");

            // Using Engine Interface, get the matrix "c" from
            // the base workspace.
            // "c" is a complex variable with a real part of cr,
            // and an imaginary part of ci
            matlab.GetFullMatrix("c", "base", ref cr, ref ci);

            // using engine interface, get the matrix "c" from
            // the base workspace.
            // "d" is a complex variable with a real part of dr,
            // and an imaginary part of di
            matlab.GetFullMatrix("d", "base", ref dr, ref di);

        }

        static private void UseDotNET(Array ar, Array ai, Array br,
            Array bi, ref Array cr, ref Array ci, ref Array dr, ref Array di)
        {
            /*
            * This function calls the math_by_numbers method from
            * inside a .NET assembly created with MATLAB using Builder
            * for .NET.
            */

            // Instantiate our .NET class from the MATLAB created component
            dotnetclass AClass = new dotnetclass();

            // explicity convert our input arguments into MWArrays
            // this can be done with implicit conversion
            MWNumericArray a = new MWNumericArray(1, 2, (double[])ar, (double[])ai);
            MWNumericArray b = new MWNumericArray(1, 2, (double[])br, (double[])bi);

            // call math_on_method from Assembly specifying the number
            // of return arguments expected and passing in a and b
            MWArray[] RetVal = AClass.math_on_numbers(2, a, b);

            // Unpack return values seperating the real and imaginary parts
            // using the ToArray method of MWNummericArray.  Since RetVal was
            // declared as a MWArray above, it must be explicity typecast here. 
            cr = ((MWNumericArray) RetVal[0]).ToVector(MWArrayComponent.Real);
            ci = ((MWNumericArray) RetVal[0]).ToVector(MWArrayComponent.Imaginary);
       
            dr = ((MWNumericArray) RetVal[1]).ToVector(MWArrayComponent.Real);
            di = ((MWNumericArray) RetVal[1]).ToVector(MWArrayComponent.Imaginary);

        }

        static private void UseClib(Array ar, Array ai, Array br,
            Array bi, ref Array cr, ref Array ci, ref Array dr, ref Array di)
        {
            /*
            * This function calls the math_by_numbers method from
            * inside a C Shared Library created with MATLAB Compiler.
            */

            // A new class Clib is used to wrap the unmanaged library.
            // http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpguide/html/cpconcreatingprototypesinmanagedcode.asp
           
            // The new class is instantiated here.
            Clib AClass = new Clib();

            AClass.DoTheWork(ar, ai, br, bi, ref cr, ref ci, ref dr, ref di);

        }

        class Clib
        {
            // Wrap all of the unmanaged functions that need to
            // be called directly using DLLImport
            // http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpguide/html/cpconconsumingunmanageddllfunctions.asp
            [DllImport("cshared.dll")]
            private static extern void mlfMath_on_numbers([In]Int32 nargout, ref IntPtr c, ref IntPtr d, [In]IntPtr a, [In]IntPtr b);

            [DllImport("cshared.dll")]
            private static extern void csharedInitialize();

            [DllImport("cshared.dll")]
            private static extern void csharedTerminate();

            [DllImport("mclmcrrt711.dll")]
            private static extern IntPtr mxCreateDoubleMatrix_730_proxy([In]Int32 numRows, [In]Int32 numCols, [In]Int32 mxComplexity);
            /*
            * typedef enum {
            *    mxREAL,
            *    mxCOMPLEX
            * } mxComplexity;
            */

            [DllImport("mclmcrrt711.dll")]
            private static extern IntPtr mxGetPr_proxy([In] IntPtr mxArray);

            [DllImport("mclmcrrt711.dll")]
            private static extern IntPtr mxGetPi_proxy([In] IntPtr mxArray);

            [DllImport("mclmcrrt711.dll")]
            private static extern void mxDestroyArray_proxy([In] IntPtr mxArray);

            [DllImport("mclmcrrt711.dll")]
            private static extern bool mclInitializeApplication_proxy(string options, Int32 count);

            [DllImport("mclmcrrt711.dll")]
            private static extern void mclTerminateApplication_proxy();

            public void DoTheWork(Array ar, Array ai, Array br, Array bi,
                ref Array cr, ref Array ci, ref Array dr, ref Array di)
            {
                //////////////////
                // Initialization
                //////////////////
               
                // Initialize MCR
                bool RetVal;
                RetVal = mclInitializeApplication_proxy("NULL",0);

                // Initalize our csharedlib
                csharedInitialize();

                //////////////////////////
                // Create Input Arguments
                //////////////////////////
                // create an mxarray to contain a and b
                IntPtr a_ptr = mxCreateDoubleMatrix_730_proxy(1, 2, 1);  /* 1 row, 2 cols, IsComplex */
                IntPtr b_ptr = mxCreateDoubleMatrix_730_proxy(1, 2, 1);  /* 1 row, 2 cols, IsComplex */
               
                // get pointer to real and imaginary parts of a
                IntPtr ar_ptr = mxGetPr_proxy(a_ptr);
                IntPtr ai_ptr = mxGetPi_proxy(a_ptr);
               
                // get pointer to real and imaginary parts of b
                IntPtr br_ptr = mxGetPr_proxy(b_ptr);
                IntPtr bi_ptr = mxGetPi_proxy(b_ptr);
               
               
                ////////////////
                // Copy In Data
                ////////////////
               
                // copy values to unmanaged array (mwArray)
                // http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpref/html/frlrfsystemruntimeinteropservicesmarshalclasswritebytetopic2.asp
                Marshal.Copy((double[])ar, 0, ar_ptr, 2);
                Marshal.Copy((double[])ai, 0, ai_ptr, 2);
                Marshal.Copy((double[])br, 0, br_ptr, 2);
                Marshal.Copy((double[])bi, 0, bi_ptr, 2);
               

                ///////////////////////////
                // Create Output Arguments
                ///////////////////////////
               
                // create pointers for return values c and d
                IntPtr c_ptr = IntPtr.Zero;
                IntPtr d_ptr = IntPtr.Zero;


                ////////////////////////////////
                // Call function from C library
                ////////////////////////////////
               
                // call math on numbers
                try
                {
                    mlfMath_on_numbers(2, ref c_ptr, ref d_ptr, a_ptr, b_ptr);
                }
                catch (Exception e)
                {
                    Console.WriteLine(e.Message);
                }

                /////////////////
                // Copy Out Data
                /////////////////
               
                // get pointer to real and imaginary parts of a
                IntPtr cr_ptr = mxGetPr_proxy(c_ptr);
                IntPtr ci_ptr = mxGetPi_proxy(c_ptr);

                // get pointer to real and imaginary parts of b
                IntPtr dr_ptr = mxGetPr_proxy(d_ptr);
                IntPtr di_ptr = mxGetPi_proxy(d_ptr);

                // copy values from unmanaged array (mwArray)
                Marshal.Copy(cr_ptr, (double[])cr, 0, 2);
                Marshal.Copy(ci_ptr, (double[])ci, 0, 2);
                Marshal.Copy(dr_ptr, (double[])dr, 0, 2);
                Marshal.Copy(di_ptr, (double[])di, 0, 2);

               
                ///////////
                // CleanUp
                ///////////
               
                // destroy mxarrays
                mxDestroyArray_proxy(a_ptr);
                mxDestroyArray_proxy(b_ptr);

                // Terminate libraries
                Clib.csharedTerminate();
                Clib.mclTerminateApplication_proxy();
           
            } // end function DoTheWork()

        } // end class Clib

        static private void DisplayMethod([In]Int16 Mode)
        {
            String Part1 = "Calling MATLAB code via ";
            String Part2 = String.Empty;
            String Empty = "";

            switch (Mode)
            {
                case 1: Part2 = Part2 + "Engine Interface."; break;
                case 2: Part2 = Part2 + ".NET Assembly."  ; break;
                case 3: Part2 = Part2 + "C Shared Library."; break;
            }

            Console.WriteLine(Empty);

            Console.WriteLine(String.Concat(Part1, Part2));

        } // end function DisplayMethod

        static private void DisplayArgs(Boolean In, [In]Array OneReal, [In]Array OneImag,
            [In]Array TwoReal, [In]Array TwoImag)
        {
            // declare variables to hold output
            String [] Labels = new String[2];
            String []  Line = new String[6];
           
            // allow for a space between each set of variables
            Line[3] = "";
           
            // setup first output line and labels
            // based on whether this is an input
            // or an output
            if (In)
            {
                // this is the first output, so
                // prepare the console
                Console.Clear();

                Line[0] = "Using input args:";
                Labels[0] = "a";
                Labels[1] = "b";
            }
            else
            {
                Line[0] = "Return Values are:";
                Labels[0] = "c";
                Labels[1] = "d";
            }
           
            // format the variable output lines
            for (int element = 0; element < 2; element++)
            {
                Line[1 + element] = String.Format("{0}({1}) = {2,5:.####} + {3,5:.####}*i", Labels[0], (element + 1), OneReal.GetValue(element), OneImag.GetValue(element));
                Line[4 + element] = String.Format("{0}({1}) = {2,5:.####} + {3,5:.####}*i", Labels[1], (element + 1), TwoReal.GetValue(element), TwoImag.GetValue(element));

            }

            // write output to screen
            Console.WriteLine("");

            for (int i = 0; i < 6; i++)
            {
                Console.WriteLine(Line[i]);
            }
           
        } // end function DisplayArgs

        static private void DisplayEnd()
        {
            ConsoleKeyInfo keypressed;

            Console.WriteLine();
            Console.WriteLine("Press any key to exit.");

            keypressed = Console.ReadKey(true);

        } // end function DisplayEnd

    } // end class Program

} // end namespace example_ML_integration

---

Error: FileLoadException was unhandled. Could not load file or assembly 'MWArray, Version 2.9.1.0, Culture = neutral, PublicKeyToken = 21d84a0da19db86f' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)

The suggested troubleshooting tip is to make sure the file is a valid .NET assembly. I'm assuming it is; I've tried to run the program with the MWArray reference both to the default path and to it's location withing C:\Program Files\MatLab and I got the same error both ways. Was there something else I was supposed to change but didn't?

It appears that the version of the referenced assembly is different from the version of the assembly that is found.
It says in the comments that MatLab assemblies should be registered in the Global Assembly Cache (GAC). Are they? (You can find out more about GAC here, and here.)

And, what exactly do you mean by "default path"? Application folder?
You can also try to delete the reference and then add it again.

Hmm... I looked at the error more closely and it says it can't load MWarray version 2.9.10. Both the local copy of MWArray and the one in gacutil are version 2.10.0.0, and the reference path in VS leads to the local copy. In the reference list it even says version 2.10.0.0. Which part of the program dictates which version of the dll to load?

The assembly references added to the project are design/compile-time references, that enable you to write the code; at runtime however, a different assembly location resolution process occurs. You can look at these articles to learn more: Resolving Names to Locations (1) [scroll down a bit to see a flowchart if you want to avoid the details], How the Runtime Locates Assemblies (2).
This normally isn't a problem and it enables a .NET app to run on any specific system (provided that the .NET framework is installed and that the required assemblies exist there).

Since you've said that the referenced assembly is the local copy, I'm guessing that the runtime checks some other locations first and finds a different version.
This can turn out to be tricky.
If you read through the articles (1) and (2), you'll see that there could be a *.config file in your project folder (or subfolder), containing some codeBase entries telling the runtime where to look. Check for these, maybe you'll find an entry with the path to the assembly that gets loaded. There's a nice short example of such .config file entries in article (1), so you can see there what it is you're looking for.
It can also help if you copy the assembly dll to the project folder, so if you havent done that, try it.
Also, you might want to try to rebuild the whole solution ("Build" menu --> "Rebuild Solution"), but I'm not sure this will help.

maybe the problem of win32 or win64 version of matlab.
try to change the VS build platform (x86 or x64)