topic Hi Ahmadi, in Intel® oneAPI Math Kernel Library

Error in mkl_sparse_z_set_value

Ahmadi__Afshin — Sun, 25 Feb 2018 23:44:02 GMT

Hello,

I am struggling to change a single value of a matrix in internal Intel Sparse BLAS format using the mkl_sparse_z_set_value function. Most of the time this function returns a value of 3. However, it does work some times! I have checked the status of memory allocation and also mkl_sparse_z_create_csr and there is no problem with them. Any idea why this issue is happening? Here is the code:

// Matrix size is Mat_Size x Mat_Size
// This matrix is going to be a diagonal matrix so the maximum number of non-zeros will be equal to Mat_Size

int Mat_Size = 10;

sparse_matrix_t Ysh_CSR = NULL;
MKL_Complex16 *Ysh_val = NULL;
MKL_INT *Ysh_col = NULL;
MKL_INT *Ysh_row = NULL;

Ysh_val = (MKL_Complex16 *)mkl_malloc(Mat_Size * sizeof(MKL_Complex16), 64);
Ysh_col = (MKL_INT *)mkl_malloc(Mat_Size * sizeof(MKL_INT), 64);
Ysh_row = (MKL_INT *)mkl_malloc((Mat_Size + 1) * sizeof(MKL_INT), 64); // +1 is because we are using 3-aaray variation

mkl_sparse_z_create_csr(&Ysh_CSR, SPARSE_INDEX_BASE_ZERO, Mat_Size, Mat_Size, Ysh_row, Ysh_row + 1, Ysh_col, Ysh_val);

MKL_Complex16 temp;
temp.real = 2 ;
temp.imag = 3 ;

int info = mkl_sparse_z_set_value(Ysh_CSR, 1, 1, temp); // set the value of Ysh_CSR[1][1] to temp

printf("info is %i", info);

Hi Ahmadi,

Ying_H_Intel — Mon, 26 Feb 2018 03:10:55 GMT

Hi Ahmadi,

Thank you for the post. We will investigate the problem and get back to you later. Could you pleas also submit the issue to https://supporttickets.intel.com/?lang=en-US, where we can track the details, like compiler/mkl version , bug etc.
Thanks

Ying

Quote:Ying H. (Intel) wrote:

Ahmadi__Afshin — Wed, 28 Feb 2018 23:24:41 GMT

Ying H. (Intel) wrote:

Hi Ahmadi,

Thank you for the post. We will investigate the problem and get back to you later. Could you pleas also submit the issue to https://supporttickets.intel.com/?lang=en-US, where we can track the details, like compiler/mkl version , bug etc.
Thanks

Ying

Dear Ying,

Were you able to investigate the problem?

Hi Ahmadi,

Ying_H_Intel — Thu, 01 Mar 2018 00:44:00 GMT

Hi Ahmadi,
Yes, we can reproduce the problem. So did you create a ticket in https://supporttickets.intel.com/?lang=en-US ? please let me know the ticket number.
Best Regards,
Ying

Quote:Ying H. (Intel) wrote:

Ahmadi__Afshin — Thu, 01 Mar 2018 02:34:38 GMT

Ying H. (Intel) wrote:

Hi Ahmadi,
Yes, we can reproduce the problem. So did you create a ticket in https://supporttickets.intel.com/?lang=en-US ? please let me know the ticket number.
Best Regards,
Ying

Hi Ying,

The ticket number is 03319553. How long do you think it is going to take to fix the issue?

Best,

Afshin

Hi Afshin,

Ying_H_Intel — Thu, 01 Mar 2018 05:55:57 GMT

Hi Afshin,

Please refer to the reply from the 03319553. It seems you are creating a csr handle, but with invalid matrix value. If there are exact value for the Ysh_row, , Ysh_col, Ysh_val, then your code will work.

SPARSE_STATUS_INVALID_VALUE = 3, /* invalid input value */

Best Regards
Ying

Quote:Ying H. (Intel) wrote:

Ahmadi__Afshin — Thu, 01 Mar 2018 19:48:10 GMT

Ying H. (Intel) wrote:

Hi Afshin,

Please refer to the reply from the 03319553. It seems you are creating a csr handle, but with invalid matrix value. If there are exact value for the Ysh_row, , Ysh_col, Ysh_val, then your code will work.

SPARSE_STATUS_INVALID_VALUE = 3, /* invalid input value */

Best Regards
Ying

Hi Yin,

My code is actually fine and there is not problem with creating the CSR handle. Ysh_$ are just empty arrays with the right memory size to keep the future sparse matrix information. However, what is wrong is that the mkl_sparse_z_set_value function can only be used after the CSR handle has been filled with values (e.g., after converting the dense matrix to sparse and storing the results in the CSR handle). I believe the language of MKL manual is vague in explaining this function. I also think Intel should include a similar function to retrieve an element from the sparse function. For example, if you add two sparse matrices together and you want to read diagonal elements of the resulting function, there is no function for that.

Anyway, I really appreciate your help in this matter.

Best,

Afshin

Hello Afshin,

MariaZh — Thu, 01 Mar 2018 21:20:12 GMT

Hello Afshin,

You're right, mkl_sparse_?_create_csr is supposed to be used only if one allocated and initialized all rows_start(_end)/col_indx and values arrays. On the basis of this information CSR handle will be created and can be used with all IE SpBLAS functionality.
mkl_sparse_?_set_value routine can only change one of the existing values from matrix to another (please, refer to https://software.intel.com/en-us/mkl-developer-reference-c-mkl-sparse-set-value). That explains why there was an error related to invalid input when passing non-initialized arrays to mkl_sparse_?_create_csr and then to mkl_sparse_?_set_value routines.
In order to retrieve an element from the resulting matrix you can use mkl_sparse_?_export_csr, however it's currently not supported to export only the part of the matrix from CSR Handle.

Hope this was helpful!

Best regards,
Maria