COMPLEX GETTRI

[apardo]

Hi! In the middle of my program i have to do an inverse of complex matrix so i do the following:

culaInt *ipiv1;
culaGetrf(DIMENSION2, DIMENSION2, mtx_w11cula, DIMENSION2,ipiv1);
culaGetri(DIMENSION2, mtx_w11cula, DIMENSION2, ipiv1);

But this closes the program in MS-DOS (the typical window problem)

mtx_w11cula is this:

-0.0105 -0.0050 0.0016 - 0.0083i 0.0016 + 0.0083i
0.0024 0.0132 0.0029 - 0.0044i 0.0029 + 0.0044i
0.0260 -0.0087 -0.0001 + 0.0082i -0.0001 - 0.0082i
0.0253 0.0019 0.0052 + 0.0046i 0.0052 - 0.0046i

If i put this in matlab and make the inverse i get:

1.0e+002 *

0.2014 0.6879 0.8301 -0.4402
-0.4653 0.5618 -0.0664 -0.1786
0.1017 + 0.5684i -1.0620 + 0.8011i -1.3393 + 0.7536i 1.5199 - 0.6162i
0.1017 - 0.5684i -1.0620 - 0.8011i -1.3393 - 0.7536i 1.5199 + 0.6162i

So, clearly it must be performed in the GPU... I have cuda 4.0 and cula r12...
Where is the problem? Thanks for your help!

[kyle]

A number of things could be going wrong...

Is your data column major? Are you checking culaStatus for errors?

[apardo]

Yes, it is column major order. Now i tried to alocate ipiv because i was not doing it.... it looks like this:

culaDeviceInt* ipiv0;
culaInt *ipiv1;
culaInt *ipiv2;

ipiv0 = (culaDeviceInt*)malloc(DIMENSION2*sizeof(culaDeviceInt));
ipiv1 = (culaInt*)malloc(DIMENSION2*sizeof(culaInt));
ipiv2 = (culaInt*)malloc(DIMENSION1*sizeof(culaInt));


status = culaDeviceSgetrf(DIMENSION2, DIMENSION2, mtx_ainv, DIMENSION2,ipiv0);
status = culaDeviceSgetri(DIMENSION2, mtx_ainv, DIMENSION2, ipiv0);

That is for the first inversion... But now the ipiv0 has, as an output, all zeros...

I think that i am alocating it well but i am not sure why does it happens...

[kyle]

Device data has to be initialized with cudaMalloc().

Please read the Programmer's Guide documentation for more information; this is covered in detail there.

[apardo]

Ahhh, thanks. That was my problem... Another question: how do i copy a matrix to, for example, the real part of a complex matrix? All in device memory... Just with cudaMemcpy?

[kyle]

The complex data is stored as an array of structures (AoS) - the data is interleaved.

[apardo]

So... Do i have to copy it manually?

[kyle]

If it's on the GPU, yes.

[apardo]

Ohhh, i was thinking about a function that copies DevicetoDevice with complex... what a pity... Thank you!!!

[kyle]

I'd recommend reading the CUDA Programmer's Guide (from NVIDIA) if you are going to use the device interface. We assume users who are using this interface (opposed to the normal host interface) are familiar with the CUDA programming model.

[apardo]

Ok! I am familiar to CUDA but I had doubts about CULA because there are almost no places to look about it!

[john]

I would recommend reading through our examples folder very carefully. It shows many different usage patterns you can use.

[apardo]

Ok, i'll take your advice. Thanks for your help!!!