PInvoke Error for FFTW

Okay, so I made a mistake. So are you ignoring everything I said? There is a "signature" in a header someplace that specifies the calling convention and the parameters, so you don't have to guess.

Sam, 

James: it appears to me that your problem is totally different. I am concerned that if either of you try to use the other's solutions then one or both of you will get confused. Something that someone suggests for one of you is likely to confuse the ohter. I suggest that you create a new thread for your situation.

Chris: the error message you got about the stack does say very clearly that the cause might be the calling convention. Therefore it makes sense to me that specifying cdecl works.

The malloc function is part of C/C++. You can find the "signature" in the headers; it is:

void * __cdecl malloc(_In_ size_t _Size);

Using that, it is clear that calling convention is cdecl.
 
I doubt however that you you need to use malloc; the .Net Interop probably have safer ways to do what you need to do.

Hello Chris,

I was also able to get a clean compile and have been running the FFTs.  However my FFT results are questionable.  I can send you what I have if you plan to get back on the project. Maybe between the two of us we can resolve issues. One of my questions is regarding the data input and output requirements since I am using the fftw_complexarray. 

Maybe you can tell me this: 
When I input my real data to the fftw_complexarray, as per my understanding, the data must be formatted as alternating real and imaginary parts.  So, if I have an an array of 4 real numbers the input to the fftw_complexarray must be of size 8 and the data copied to the fftw_complexarray needs to look like: real_1,Imag_1, real_2,Imag_2, real_3,Imag_3, real_4,Imag_4. Where all Imaginary data is initially set to "0".

Following the FFT execution I perform addition calculations on the FFT output, and likewise my understanding is that the FFT output data is formatted in the array as:  real_1,Imag_1, real_2,Imag_2, real_3,Imag_3, real_4,Imag_4, ...

I am trying to execute a Phase_Correlation on two 1-D real data arrays using the example provided at:
http://nashruddin.com/phase-correlation-function-in-opencv.html
Once successful I'll go for the 2-D array (two images).

Thanks
James

Jim,

Hello Chris,

I'm been working down the same path over the past two weeks trying to use the following:

dll is from http://www.fftw.org

wrapper class is from http://www.sdss.jhu.edu/~tamas/bytes/fftwcsharp.html

I am hopping you can help me with a few issues I'm having in implementing this class/wrapper successfully as there is not much info I can find.  If so, I will post my question here.

Thanks
Jim

Hi Chris

What do you mean by  the calling convention change Chris

try modifying the signature to unit16 / uint32
I remember size_t is typedef for unsinged int
IntPtr malloc(uint16 length);  
IntPtr malloc(uint32 length);  

I think I just solved this...it seems to be in the DllImport arguments.  I kept thinking that I have sent every datatype and still have the exact same issue so I tried to understand all the modifiers (still do not understand all of them).  However, I found an obscure reference that said something like "if you keep getting this error, try setting the CallingConvention = Cdecl.  That did it.  However, I have to change the entire wrapper class as this happens on each and every function exported.

I m pretty sure that the problem comes from the unmanaged code. Verify if the given unmanaged libray has dependencies on other libraries, you know the function that you call could call anther code source outside the assembly

Try to use this argument staff instead

IntPtr

int

UIntPtr  because size_t is an unsigned and Inptr change its size dynamically to fit the variable size

long

Or this one

IntPtr

int

IntPtr

long

nope, this is all 32-bit...PC, OS (Windows XP Pro 2002, SP 3) with the 32-bit dll.

The parameter issue couldn't only be the unique raison (Of Corse you verify the parameter number,order and size) It could be also a bug witihin the unmanaged code, I mean the invoked native function unbalances the  stack because of a given  bug.

I remember  I have read a good artile for simila issue, I thing this one
http://msdn.microsoft.com/en-us/magazine/cc163606.aspx

Meanwhile, I give you and alternative solution, if you have the unmanaged library then you could wrap up it and use it, I invite you to take a look on my articles in  this  context
http://www.c-sharpcorner.com/UploadFile/yougerthen/510262008060749AM/5.aspx?ArticleID=d2da1ab3-b92d-499d-94cd-bf54d91e14c3

Sorry but I didn't see any screenshot, Now I see it OK

Please send the detail error or exception that happens when you run the code

Target Framework: .NET Framework 4 Client Profile.

Hi
Are you using 3.5 or 4.0, because the 4.0 resolves you problem by using optional parameters