Hi everyone,

My plan is to write some methods that use eigen and create a class library dll that gets called from a c# program. I had it working when I was using MatrixXf, but when I use SparseMatrix, I get the following error:

AccessViolationException was unhandled
Attempted to read or write protected memory. This is often an indication that other memory is corrupt.

The c# code that calls the method resembles the following:

Code: Select all

            unsafe
            {
                fixed (float* oldPointer = &oldData[0])
                {
                    fixed (float* newPointer = &newData[0])
                    {
                        someclass.somemethod(newPointer, oldPointer);
                    }
                }
            }


and in the .dll file I have something like the following:

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void someclass::somemethod(float outArray[], float inarray[])
{

 SparseMatrix<float> A(L, L);
 A.coeffRef(0, 0) = 1;
}


where the error is caused by the line

Code: Select all

A.coeffRef(0, 0) = 1;


whereas something like

Code: Select all

void someclass::somemethod(float outArray[], float inarray[])
{
 MatrixXf A(L, L);
 A(0, 0) = 1;
}


works fine. I realize that C# probably doesn't approve of something about how sparse matrices are stored in memory, but might there be an easy workaround?

oops, needed to declare it as DynamicSparseMatrix in order to define its indices like that.