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My test model comprises of 370000x370000 size coeff and jacobian matrix. In single iteration, both set take around 36 and 65 sec respectively for phases 11,22 and 33 . System configuration is Xeon 3.46 GHz 4-core with 20GB RAM.

I would like to solve one iteration of at least 1millionx1million size model in 60 sec. including both symmetric and unsymmetric set. When I ran Ansys on same system with this size it hardly took 30 sec to solve 4 iterations (each iteration include one symmetric and one unsymmetric set). Any suggestion to increase the performance will be greatly appreciated.

Thanks,

Ashish

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10 Replies

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Please make sure you are running threaded version of MKL. You should link with libmkl_intel_thread library for this, please refer to MKl link line adviser:

http://software.intel.com/en-us/articles/intel-mkl-link-line-advisor/

You may also look how many threads was used by PARDISO by setting msglvl=1.

Regards,

Konstantin

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Could you set msglvl to 1 and include PARDISO output to this topic? It could help us to provide you some advices.

With best regards,

Alexander Kalinkin

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I am using threaded MKL and my OS is windows xp. I have following libs included in my project

mkl_solver_lp64.lib

mkl_intel_lp64.lib

mkl_intel_thread.lib

mkl_core.lib

libiomp5md.lib

Here is output for unsymmetric jacobian

**================ PARDISO: solving a real struct. sym. system ================**

The local (internal) PARDISO version is : 103000116

1-based array indexing is turned ON

PARDISO double precision computation is turned ON

METIS algorithm at reorder step is turned ON

Scaling is turned ON

Matching is turned ON

Summary: ( reordering phase )

================

Times:

======

Time spent in calculations of symmetric matrix portrait(fulladj): 0.009621 s

Time spent in reordering of the initial matrix(reorder) : 2.682449 s

Time spent in symbolic factorization(symbfct) : 0.701643 s

Time spent in data preparations for factorization(parlist) : 0.033879 s

Time spent in allocation of internal data structures(malloc) : 0.066773 s

Time spent in additional calculations : 0.336471 s

Total time spent : 3.830835 s

Statistics:

===========

< Parallel Direct Factorization with #processors: > 6

< Numerical Factorization with BLAS3 and O(n) synchronization >

< Linear system Ax = b>

#equations: 372745

#non-zeros in A: 5495763

non-zeros in A (): 0.003956

#right-hand sides: 1

< Factors L and U >

#columns for each panel: 72

#independent subgraphs: 0

< Preprocessing with state of the art partitioning metis>

#supernodes: 154074

size of largest supernode: 3960

number of nonzeros in L 268393909

number of nonzeros in U 260128570

number of nonzeros in L+U 528522479

=== PARDISO is running in In-Core mode, because iparam(60)=0 ===

Percentage of computed non-zeros for LL^T factorization

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================ PARDISO: solving a real struct. sym. system ================

Single-level factorization algorithm is turned ON

Summary: ( factorization phase )

================

Times:

======

Time spent in copying matrix to internal data structure(A to LU): 0.000000 s

Time spent in factorization step(numfct) : 51.146111 s

Time spent in allocation of internal data structures(malloc) : 0.000339 s

Time spent in additional calculations : 0.000001 s

Total time spent : 51.146451 s

Statistics:

===========

< Parallel Direct Factorization with #processors: > 6

< Numerical Factorization with BLAS3 and O(n) synchronization >

< Linear system Ax = b>

#equations: 372745

#non-zeros in A: 5495763

non-zeros in A (): 0.003956

#right-hand sides: 1

< Factors L and U >

#columns for each panel: 72

#independent subgraphs: 0

< Preprocessing with state of the art partitioning metis>

#supernodes: 154074

size of largest supernode: 3960

number of nonzeros in L 268393909

number of nonzeros in U 260128570

number of nonzeros in L+U 528522479

gflop for the numerical factorization: 1708.338114

gflop/s for the numerical factorization: 33.401134

================ PARDISO: solving a real struct. sym. system ================

Summary: ( solution phase )

================

Times:

======

Time spent in direct solver at solve step (solve) : 0.316364 s

Time spent in additional calculations : 0.631197 s

Total time spent : 0.947561 s

Statistics:

===========

< Parallel Direct Factorization with #processors: > 6

< Numerical Factorization with BLAS3 and O(n) synchronization >

< Linear system Ax = b>

#equations: 372745

#non-zeros in A: 5495763

non-zeros in A (): 0.003956

#right-hand sides: 1

< Factors L and U >

#columns for each panel: 72

#independent subgraphs: 0

< Preprocessing with state of the art partitioning metis>

#supernodes: 154074

size of largest supernode: 3960

number of nonzeros in L 268393909

number of nonzeros in U 260128570

number of nonzeros in L+U 528522479

gflop for the numerical factorization: 1708.338114

gflop/s for the numerical factorization: 33.401134

The local (internal) PARDISO version is : 103000116

1-based array indexing is turned ON

PARDISO double precision computation is turned ON

METIS algorithm at reorder step is turned ON

Scaling is turned ON

Matching is turned ON

Summary: ( reordering phase )

================

Times:

======

Time spent in calculations of symmetric matrix portrait(fulladj): 0.009621 s

Time spent in reordering of the initial matrix(reorder) : 2.682449 s

Time spent in symbolic factorization(symbfct) : 0.701643 s

Time spent in data preparations for factorization(parlist) : 0.033879 s

Time spent in allocation of internal data structures(malloc) : 0.066773 s

Time spent in additional calculations : 0.336471 s

Total time spent : 3.830835 s

Statistics:

===========

< Parallel Direct Factorization with #processors: > 6

< Numerical Factorization with BLAS3 and O(n) synchronization >

< Linear system Ax = b>

#equations: 372745

#non-zeros in A: 5495763

non-zeros in A (): 0.003956

#right-hand sides: 1

< Factors L and U >

#columns for each panel: 72

#independent subgraphs: 0

< Preprocessing with state of the art partitioning metis>

#supernodes: 154074

size of largest supernode: 3960

number of nonzeros in L 268393909

number of nonzeros in U 260128570

number of nonzeros in L+U 528522479

=== PARDISO is running in In-Core mode, because iparam(60)=0 ===

Percentage of computed non-zeros for LL^T factorization

0 %

1 %

2 %

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================ PARDISO: solving a real struct. sym. system ================

Single-level factorization algorithm is turned ON

Summary: ( factorization phase )

================

Times:

======

Time spent in copying matrix to internal data structure(A to LU): 0.000000 s

Time spent in factorization step(numfct) : 51.146111 s

Time spent in allocation of internal data structures(malloc) : 0.000339 s

Time spent in additional calculations : 0.000001 s

Total time spent : 51.146451 s

Statistics:

===========

< Parallel Direct Factorization with #processors: > 6

< Numerical Factorization with BLAS3 and O(n) synchronization >

< Linear system Ax = b>

#equations: 372745

#non-zeros in A: 5495763

non-zeros in A (): 0.003956

#right-hand sides: 1

< Factors L and U >

#columns for each panel: 72

#independent subgraphs: 0

< Preprocessing with state of the art partitioning metis>

#supernodes: 154074

size of largest supernode: 3960

number of nonzeros in L 268393909

number of nonzeros in U 260128570

number of nonzeros in L+U 528522479

gflop for the numerical factorization: 1708.338114

gflop/s for the numerical factorization: 33.401134

================ PARDISO: solving a real struct. sym. system ================

Summary: ( solution phase )

================

Times:

======

Time spent in direct solver at solve step (solve) : 0.316364 s

Time spent in additional calculations : 0.631197 s

Total time spent : 0.947561 s

Statistics:

===========

< Parallel Direct Factorization with #processors: > 6

< Numerical Factorization with BLAS3 and O(n) synchronization >

< Linear system Ax = b>

#equations: 372745

#non-zeros in A: 5495763

non-zeros in A (): 0.003956

#right-hand sides: 1

< Factors L and U >

#columns for each panel: 72

#independent subgraphs: 0

< Preprocessing with state of the art partitioning metis>

#supernodes: 154074

size of largest supernode: 3960

number of nonzeros in L 268393909

number of nonzeros in U 260128570

number of nonzeros in L+U 528522479

gflop for the numerical factorization: 1708.338114

gflop/s for the numerical factorization: 33.401134

I could not print same for symmteric coefficient matrix as output string length exceeded limit of windows command window. Here is partial output. I will try some other way to print it

**================**

Times:

======

Time spent in copying matrix to internal data structure(A to LU): 0.000000 s

Time spent in factorization step(numfct) : 23.408378 s

Time spent in allocation of internal data structures(malloc) : 0.000514 s

Time spent in additional calculations : 0.000001 s

Total time spent : 23.408893 s

Statistics:

===========

< Parallel Direct Factorization with #processors: > 6

< Numerical Factorization with BLAS3 and O(n) synchronization >

< Linear system Ax = b>

#equations: 372745

#non-zeros in A: 2934254

non-zeros in A (): 0.002112

#right-hand sides: 1

< Factors L and U >

#columns for each panel: 96

#independent subgraphs: 0

< Preprocessing with state of the art partitioning metis>

#supernodes: 153764

size of largest supernode: 3960

number of nonzeros in L 269145349

number of nonzeros in U 1

number of nonzeros in L+U 269145350

gflop for the numerical factorization: 869.989754

gflop/s for the numerical factorization: 37.165742

================ PARDISO: solving a symm. posit. def. system ================

Summary: ( solution phase )

================

Times:

======

Time spent in direct solver at solve step (solve) : 0.298444 s

Time spent in additional calculations : 0.619958 s

Total time spent : 0.918402 s

Statistics:

===========

< Parallel Direct Factorization with #processors: > 6

< Numerical Factorization with BLAS3 and O(n) synchronization >

< Linear system Ax = b>

#equations: 372745

#non-zeros in A: 2934254

non-zeros in A (): 0.002112

#right-hand sides: 1

< Factors L and U >

#columns for each panel: 96

#independent subgraphs: 0

< Preprocessing with state of the art partitioning metis>

#supernodes: 153764

size of largest supernode: 3960

number of nonzeros in L 269145349

number of nonzeros in U 1

number of nonzeros in L+U 269145350

gflop for the numerical factorization: 869.989754

gflop/s for the numerical factorization: 37.165742

Times:

======

Time spent in copying matrix to internal data structure(A to LU): 0.000000 s

Time spent in factorization step(numfct) : 23.408378 s

Time spent in allocation of internal data structures(malloc) : 0.000514 s

Time spent in additional calculations : 0.000001 s

Total time spent : 23.408893 s

Statistics:

===========

< Parallel Direct Factorization with #processors: > 6

< Numerical Factorization with BLAS3 and O(n) synchronization >

< Linear system Ax = b>

#equations: 372745

#non-zeros in A: 2934254

non-zeros in A (): 0.002112

#right-hand sides: 1

< Factors L and U >

#columns for each panel: 96

#independent subgraphs: 0

< Preprocessing with state of the art partitioning metis>

#supernodes: 153764

size of largest supernode: 3960

number of nonzeros in L 269145349

number of nonzeros in U 1

number of nonzeros in L+U 269145350

gflop for the numerical factorization: 869.989754

gflop/s for the numerical factorization: 37.165742

================ PARDISO: solving a symm. posit. def. system ================

Summary: ( solution phase )

================

Times:

======

Time spent in direct solver at solve step (solve) : 0.298444 s

Time spent in additional calculations : 0.619958 s

Total time spent : 0.918402 s

Statistics:

===========

< Parallel Direct Factorization with #processors: > 6

< Numerical Factorization with BLAS3 and O(n) synchronization >

< Linear system Ax = b>

#equations: 372745

#non-zeros in A: 2934254

non-zeros in A (): 0.002112

#right-hand sides: 1

< Factors L and U >

#columns for each panel: 96

#independent subgraphs: 0

< Preprocessing with state of the art partitioning metis>

#supernodes: 153764

size of largest supernode: 3960

number of nonzeros in L 269145349

number of nonzeros in U 1

number of nonzeros in L+U 269145350

gflop for the numerical factorization: 869.989754

gflop/s for the numerical factorization: 37.165742

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I am copying part of code which set the input and control flags for both symmetric and unsymmteric solver. This may be helpful.

Thanks,

Ashish

INPUT AND CONTROL FLAG FOR SYMMETRIC

**MKL_INT l_nMTYPE = 2; /* Real symmetric matrix and positive definite*/**

/* RHS and solution vectors. */

MKL_INT l_nNRHS = 1; /* Number of right hand sides. */

/* Internal solver memory pointer l_pMemPt, */

/* 32-bit: int l_pMemPt[64]; 64-bit: long int l_pMemPt[64] */

/* or void *l_pMemPt[64] should be OK on both architectures */

#ifdef WIN64

long int l_pMemPt[64];

#else

int l_pMemPt[64];

#endif

/* Pardiso control parameters. */

MKL_INT l_nIPARM[64];

MKL_INT l_nMAXFCT, l_nMNUM, l_nPHASE, l_nERROR, l_nMSGLVL;

/* Auxiliary variables. */

double l_dDDUM; /* Double dummy */

MKL_INT l_nIDUM; /* Integer dummy. */

/* -------------------------------------------------------------------- */

/* .. Setup Pardiso control parameters. */

/* -------------------------------------------------------------------- */

for(int i = 0; i < 64; i++)

l_nIPARM

/* RHS and solution vectors. */

MKL_INT l_nNRHS = 1; /* Number of right hand sides. */

/* Internal solver memory pointer l_pMemPt, */

/* 32-bit: int l_pMemPt[64]; 64-bit: long int l_pMemPt[64] */

/* or void *l_pMemPt[64] should be OK on both architectures */

#ifdef WIN64

long int l_pMemPt[64];

#else

int l_pMemPt[64];

#endif

/* Pardiso control parameters. */

MKL_INT l_nIPARM[64];

MKL_INT l_nMAXFCT, l_nMNUM, l_nPHASE, l_nERROR, l_nMSGLVL;

/* Auxiliary variables. */

double l_dDDUM; /* Double dummy */

MKL_INT l_nIDUM; /* Integer dummy. */

/* -------------------------------------------------------------------- */

/* .. Setup Pardiso control parameters. */

/* -------------------------------------------------------------------- */

for(int i = 0; i < 64; i++)

l_nIPARM

*= 0;*

l_nIPARM[0] = 1; /* No solver default */

l_nIPARM[1] = 2; /* Fill-in reordering from METIS */

/* Numbers of processors, value of OMP_NUM_THREADS */

l_nIPARM[2] = 0; //use all the available processors

l_nIPARM[3] = 0; /* No iterative-direct algorithm */

l_nIPARM[4] = 0; /* No user fill-in reducing permutation */

l_nIPARM[5] = 0; /* Write solution into x */

l_nIPARM[6] = 0; /* Not in use */

l_nIPARM[7] = 2; /* Max numbers of iterative refinement steps */

l_nIPARM[8] = 0; /* Not in use */

l_nIPARM[9] = 13; /* Perturb the pivot elements with 1E-13 */

l_nIPARM[10] = 1; /* Use nonsymmetric permutation and scaling MPS */

l_nIPARM[11] = 0; /* Not in use */

l_nIPARM[12] = 0; /* Maximum weighted matching algorithm is switched-off (default for symmetric). Try l_nIPARM[12] = 1 in case of inappropriate accuracy */

l_nIPARM[13] = 0; /* Output: Number of perturbed pivots */

l_nIPARM[14] = 0; /* Not in use */

l_nIPARM[15] = 0; /* Not in use */

l_nIPARM[16] = 0; /* Not in use */

l_nIPARM[17] = 0; /* Output: Number of nonzeros in the factor LU */

l_nIPARM[18] = 0; /* Output: Mflops for LU factorization */

l_nIPARM[19] = 0; /* Output: Numbers of CG Iterations */

l_nMAXFCT = 1; /* Maximum number of numerical factorizations. */

l_nMNUM = 1; /* Which factorization to use. */

l_nMSGLVL = 0; /* do not Print statistical information in file */

l_nERROR = 0; /* Initialize l_nERROR flag */

/* -------------------------------------------------------------------- */

/* .. Initialize the internal solver memory pointer. This is only */

/* necessary for the FIRST call of the PARDISO solver. */

/* -------------------------------------------------------------------- */

for (int i = 0; i < 64; i++)

l_pMemPtl_nIPARM[0] = 1; /* No solver default */

l_nIPARM[1] = 2; /* Fill-in reordering from METIS */

/* Numbers of processors, value of OMP_NUM_THREADS */

l_nIPARM[2] = 0; //use all the available processors

l_nIPARM[3] = 0; /* No iterative-direct algorithm */

l_nIPARM[4] = 0; /* No user fill-in reducing permutation */

l_nIPARM[5] = 0; /* Write solution into x */

l_nIPARM[6] = 0; /* Not in use */

l_nIPARM[7] = 2; /* Max numbers of iterative refinement steps */

l_nIPARM[8] = 0; /* Not in use */

l_nIPARM[9] = 13; /* Perturb the pivot elements with 1E-13 */

l_nIPARM[10] = 1; /* Use nonsymmetric permutation and scaling MPS */

l_nIPARM[11] = 0; /* Not in use */

l_nIPARM[12] = 0; /* Maximum weighted matching algorithm is switched-off (default for symmetric). Try l_nIPARM[12] = 1 in case of inappropriate accuracy */

l_nIPARM[13] = 0; /* Output: Number of perturbed pivots */

l_nIPARM[14] = 0; /* Not in use */

l_nIPARM[15] = 0; /* Not in use */

l_nIPARM[16] = 0; /* Not in use */

l_nIPARM[17] = 0; /* Output: Number of nonzeros in the factor LU */

l_nIPARM[18] = 0; /* Output: Mflops for LU factorization */

l_nIPARM[19] = 0; /* Output: Numbers of CG Iterations */

l_nMAXFCT = 1; /* Maximum number of numerical factorizations. */

l_nMNUM = 1; /* Which factorization to use. */

l_nMSGLVL = 0; /* do not Print statistical information in file */

l_nERROR = 0; /* Initialize l_nERROR flag */

/* -------------------------------------------------------------------- */

/* .. Initialize the internal solver memory pointer. This is only */

/* necessary for the FIRST call of the PARDISO solver. */

/* -------------------------------------------------------------------- */

for (int i = 0; i < 64; i++)

l_pMemPt

*= 0;*

/* -------------------------------------------------------------------- */

/* .. Reordering and Symbolic Factorization. This step also allocates */

/* all memory that is necessary for the factorization. */

/* -------------------------------------------------------------------- */

l_nPHASE = 11;

PARDISO (l_pMemPt, &l_nMAXFCT, &l_nMNUM, &l_nMTYPE, &l_nPHASE,

&m_nNodeCnt, l_pAX, l_pRowIdx, l_pCol, &l_nIDUM, &l_nNRHS,

l_nIPARM, &l_nMSGLVL, &l_dDDUM, &l_dDDUM, &l_nERROR);/* -------------------------------------------------------------------- */

/* .. Reordering and Symbolic Factorization. This step also allocates */

/* all memory that is necessary for the factorization. */

/* -------------------------------------------------------------------- */

l_nPHASE = 11;

PARDISO (l_pMemPt, &l_nMAXFCT, &l_nMNUM, &l_nMTYPE, &l_nPHASE,

&m_nNodeCnt, l_pAX, l_pRowIdx, l_pCol, &l_nIDUM, &l_nNRHS,

l_nIPARM, &l_nMSGLVL, &l_dDDUM, &l_dDDUM, &l_nERROR);

INPUT AND CONTROL FLAG FOR UNSYMMETRIC

INPUT AND CONTROL FLAG FOR UNSYMMETRIC

**/* -------------------------------------------------------------------- */**

/* .. Initialize the internal solver memory pointer. This is only */

/* necessary for the FIRST call of the PARDISO solver. */

/* -------------------------------------------------------------------- */

m_pMemPt = new MEMPTR[64];

for (int i = 0; i < 64; i++)

m_pMemPt/* .. Initialize the internal solver memory pointer. This is only */

/* necessary for the FIRST call of the PARDISO solver. */

/* -------------------------------------------------------------------- */

m_pMemPt = new MEMPTR[64];

for (int i = 0; i < 64; i++)

m_pMemPt

*= 0;*

m_nMTYPE = 1; /* Real structurally symmetric matrix */

/* RHS and solution vectors. */

m_nNRHS = 1; /* Number of right hand sides. */

/* Pardiso control parameters. */

m_nIPARM = new MKL_INT[64];

/* -------------------------------------------------------------------- */

/* .. Pardiso control parameters. */

/* -------------------------------------------------------------------- */

for(int i = 0; i < 64; i++)

m_nIPARMm_nMTYPE = 1; /* Real structurally symmetric matrix */

/* RHS and solution vectors. */

m_nNRHS = 1; /* Number of right hand sides. */

/* Pardiso control parameters. */

m_nIPARM = new MKL_INT[64];

/* -------------------------------------------------------------------- */

/* .. Pardiso control parameters. */

/* -------------------------------------------------------------------- */

for(int i = 0; i < 64; i++)

m_nIPARM

*= 0;*

m_nIPARM[0] = 1; /* No solver default */

m_nIPARM[1] = 2; /* Fill-in reordering from METIS the solver uses the nested dissection algorithm from the METIS */

/* Numbers of processors, value of MKL_NUM_THREADS. If the variable MKL_NUM_THREADS is not defined, then the solver uses all available processors */

m_nIPARM[2] = 0; //currently is not used

m_nIPARM[3] = 0; /* No iterative-direct algorithm */

m_nIPARM[4] = 0; /* No user fill-in reducing permutation */

m_nIPARM[5] = 0; /* Write solution into x */

m_nIPARM[6] = 0; /* Not in use */

m_nIPARM[7] = 2; /* Max numbers of iterative refinement steps */

m_nIPARM[8] = 0; /* This parameter is reserved for future use. Its value must be set to 0 */

m_nIPARM[9] = 13; /* Perturb the pivot elements with 1E-13 */

m_nIPARM[10] = 1; /* Use nonsymmetric permutation and scaling MPS */

m_nIPARM[11] = 0; /* PARDISO solves a linear system Ax = b (default value). */

m_nIPARM[12] = 1; /* Maximum weighted matching algorithm is switched-off (default for symmetric). Try m_nIPARM[12] = 1 in case of inappropriate accuracy */

m_nIPARM[13] = 0; /* Output: Number of perturbed pivots */

m_nIPARM[14] = 0; /* Not in use */

m_nIPARM[15] = 0; /* Not in use */

m_nIPARM[16] = 0; /* Not in use */

m_nIPARM[17] = 0; /* Output: Number of nonzeros in the factor LU */

m_nIPARM[18] = 0; /* Output: Mflops for LU factorization */

m_nIPARM[19] = 0; /* Output: Numbers of CG Iterations */

m_nMAXFCT = 1; /* Maximum number of numerical factorizations. */

m_nMNUM = 1; /* Which factorization to use. */

m_nMSGLVL = 0; /* do not Print statistical information in file */

m_nERROR = 0; /* Initialize m_nERROR flag */

m_nPHASE = 11;

PARDISO (m_pMemPt, &m_nMAXFCT, &m_nMNUM, &m_nMTYPE, &m_nPHASE,

&m_nXSize, m_dAX, m_nRowIdx, m_nCol, &m_nIDUM, &m_nNRHS,

m_nIPARM, &m_nMSGLVL, &m_dDDUM, &m_dDDUM, &m_nERROR);

m_nIPARM[0] = 1; /* No solver default */

m_nIPARM[1] = 2; /* Fill-in reordering from METIS the solver uses the nested dissection algorithm from the METIS */

/* Numbers of processors, value of MKL_NUM_THREADS. If the variable MKL_NUM_THREADS is not defined, then the solver uses all available processors */

m_nIPARM[2] = 0; //currently is not used

m_nIPARM[3] = 0; /* No iterative-direct algorithm */

m_nIPARM[4] = 0; /* No user fill-in reducing permutation */

m_nIPARM[5] = 0; /* Write solution into x */

m_nIPARM[6] = 0; /* Not in use */

m_nIPARM[7] = 2; /* Max numbers of iterative refinement steps */

m_nIPARM[8] = 0; /* This parameter is reserved for future use. Its value must be set to 0 */

m_nIPARM[9] = 13; /* Perturb the pivot elements with 1E-13 */

m_nIPARM[10] = 1; /* Use nonsymmetric permutation and scaling MPS */

m_nIPARM[11] = 0; /* PARDISO solves a linear system Ax = b (default value). */

m_nIPARM[12] = 1; /* Maximum weighted matching algorithm is switched-off (default for symmetric). Try m_nIPARM[12] = 1 in case of inappropriate accuracy */

m_nIPARM[13] = 0; /* Output: Number of perturbed pivots */

m_nIPARM[14] = 0; /* Not in use */

m_nIPARM[15] = 0; /* Not in use */

m_nIPARM[16] = 0; /* Not in use */

m_nIPARM[17] = 0; /* Output: Number of nonzeros in the factor LU */

m_nIPARM[18] = 0; /* Output: Mflops for LU factorization */

m_nIPARM[19] = 0; /* Output: Numbers of CG Iterations */

m_nMAXFCT = 1; /* Maximum number of numerical factorizations. */

m_nMNUM = 1; /* Which factorization to use. */

m_nMSGLVL = 0; /* do not Print statistical information in file */

m_nERROR = 0; /* Initialize m_nERROR flag */

m_nPHASE = 11;

PARDISO (m_pMemPt, &m_nMAXFCT, &m_nMNUM, &m_nMTYPE, &m_nPHASE,

&m_nXSize, m_dAX, m_nRowIdx, m_nCol, &m_nIDUM, &m_nNRHS,

m_nIPARM, &m_nMSGLVL, &m_dDDUM, &m_dDDUM, &m_nERROR);

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Sorry for delay. It's really strange that PARDISO return number of threads is equal to 6 on your 4 cores Xeon. Did you change default number of threads used by MKL?

With best regards,

Alexander Kalinkin

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Thanks for reply.

Yes. When I first reported this in forum I had changed MKL_NUM_THREADS=4 on this 6-core machine. Later I removed it and thats why you see 6-cores printed by PARDISO.

Thanks,

Ashish

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It indicates the advisability of putting some effort into examining whether the equations have a band structure and whether that bandwidth can be reduced by reordering.

Some background information, on how the equations were originated, may help.

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One additional question: What kind of solver from Ansys so you use?

With best regards,

Alexander Kalinkin

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Thanks for reply.

These equations are derived from finite element formulation of heat conduction equation using 4 noded TET. Heat conduction equations have convection boundary condition defined for all the boundaries.

Actually, I do use reverse cuthill methd to reduce band width of matrix and all the data I had shared earlier is after bandwidth minimization. I have seen reduction in computaional time after minimization of bandwidth. I am not sure if it will always be benficial to reduce the bandwidth because it may not be useful for sprase solver.

Thanks,

Ashish

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I use Ansys Mechanical to solve nonlinear equations. I chose Sparse Solver and Newton Raphson from the option list of Ansys.

Thanks,

Ashish

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