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You could write code to unpack and access it I suppose, but if you're asking whether there is an easyway to access it or have MKL functions act upon it (as there is in LAPACK by specifying the first element and an appropriate leading dimension parameter as the stride) then I believe the answer is no.

Todd

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`values`,

`columns`,

`pointerB`, and

`pointerE`. And the second variation is specified by three arrays:values, columns and rowIndex as you described above.Some MKLSparse BLAS routines can only works with the three arraysvarition of the CSR, all other routines can work with the both variations.

Compared to the classical three arrays variation of CSR mentioned by you, the NIST variation with four arraysallows working with submatrices. You just need to define

`pointerB`and

`pointerE arraysproperly`. You don't need to form additional the values and columns arrays since all sparse representations of submatrices can use only one copy of these arrays.

Hope it helps

All the best

Sergey

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*= {0, 3, 5, 8, 11};*

*= {3, 5, 8, 11, 13};*

**mkl_scsrmv**

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Hello Vahid,

Your submatrix can be defined as follows:

int pointerB[3]={2, 3, 5} , pointerE[3]={3,3,8};

Here is a code example where submatrix is multiplied by vector {3,4, 5) with the help of mkl_dcsrmv

int main() {

//*******************************************************************************

// Declaration and initialization of parameters for sparse representation of

// the matrix A in the compressed sparse row format:

//*******************************************************************************

#define M 5

#define NNZ 13

#define MN

double values[NNZ] = {1.0, -1.0, -3.0, -1.0, 5.0, 4.0, 6.0, 4.0, -3.0, 6.0, 7.0, 4.0, -5.0};

int columns[NNZ] = {0, 1, 3, 0, 1, 2, 3, 4, 0, 2, 3, 2, 4};

int rowIndex[M+1] = {0, 3, 5, 8, 11, 13};

double sol_vec

double rhs_vec

double alpha=1.0, beta=0.0;

int pointerB[3]={2, 3, 5} , pointerE[3]={3,3,8};

char transa;

char matdescra[6];

int i, ishift, mn=3;

transa = 'n';

matdescra[0] = 'g';

matdescra[3] = 'c';

ishift=pointerB[0];

mkl_dcsrmv(&transa, &mn, &mn, α, matdescra,&values[ishift], &columns[ishift], pointerB, pointerE, sol_vec, β, rhs_vec);

for (i = 0; i < mn; i++) {

printf("%7.1f\n", rhs_vec*); };}As concerns as m and k, I'd recommend to use dimensions of the submatrix. All the bestSergey*

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