Introduction

The release of PARDISO 4.0.0 from the University of Basel is not backward compatible and thus introduces some incompatibilities with the implementation of PARDISO that is available with the Intel® Math Kernel Library. This article outlines those places where the two interfaces have diverged.

PARDISO 4.0.0 introduces the additional routine pardisoinit which is to be called before the pardiso routine. Intel® MKL PARDISO does not have such a routine.

In version 10.2 Update 6, Intel® MKL PARDISO introduces an additional interface function: pardiso_64. This interface is identical to that of pardiso except that it accepts and returns all integer data in the INTEGER*8 type. This new interface is supported only in the 64-bit Intel MKL libraries. PARDISO will return an error code (-12) if a program calling pardiso_64 is linked to the 32-bit libraries.

Routine arguments differences

PARDISO* 4.0.0 has additional argument dparm array of type REAL and length 64 that is used for a multi-recursive iterative linear solver. Intel® MKL PARDISO has no support for this solver and no argument dparm in the API. The two tables below outline the differences in the arguments to the respective PARDISO functions and the differences in interpretation of the IPARM array. A full description of the arguments and IPARM array for Intel MKL can be found in the PARDISO Parameter Tables.

PARDISO arguments compared

Argument name	Argument type	PARDISO* 4.0.0	Intel® MKL PARDISO
pt(64)	INTEGER	Content of array is different (for internal use only)
maxfct	INTEGER	same
mnum	INTEGER	same
mtype	INTEGER	same
phase	INTEGER	Use iparm(26) to split forward/backward substitutions	Stages 331-333 added to perform forward, diagonal, and backward substitution
n	INTEGER	same
a	REAL/COMPLEX	same
ia(n+1)	INTEGER		Supports 0-based indexing
ja(*)	INTEGER		Supports 0-based indexing
perm(n)	INTEGER	same
nrhs	INTEGER	same
iparm(64)	INTEGER	Meaning of array entries is different (see the table below)
msglvl	INTEGER		Cannot print multi-recursive iterative solver statistics (no such solver)
b(n,nrhs)	REAL/COMPLEX	same
x(n,nrhs)	REAL/COMPLEX	same
error	INTEGER	Error code -9 is not used -10 means no license file found -11 means license file expired -12 means wrong username or hostname	-9 means not enough memory for OOC -10 means problems with OOC temp files -11 means read/write problems with the OOC data file Error codes -12, -100, -101, -102, -103 are not used
dparm(64)	REAL		Not present in the argument list

The IPARM arrays compared

Id	PARDISO* 4.0.0		Intel® MKL PARDISO
2	Minimum degree and nested dissection algorithm		Minimum degree, nested dissection and parallel version of the nested dissection algorithm
3	Number of processors		Not used (MKL_NUM_THREADS environment variable and functions are used instead)
12	Solving the system with transpose matrix		Not used
24	Parallel numerical factorization		Not used
25	Parallel forward/backward solve		Not used
26	Splitting of forward/backward solve		Not used (use argument phase instead)
27	Not used	Matrix checker
28	Parallel reordering for METIS		Single or double precision of PARDISO (for parallel reordering use iparm(2))
29	Switch between 32-bit and 64-bit factorization		Not used (use iparm(28) to control accuracy)
30	Control the size of the supernodes		Zero or negative pivots info
31	Partial solve for sparse right-hand side and sparse solution		Not used
32	Use the multi-recursive iterative linear solver		Not used
33	Determinant of a real symmetric indefinite matrix		Not used
34	Identical solution independent on the number of processors		Not used
35	Not used		MKL 10.2.*: Not used
			MKL 10.3.0: C or Fortran style array indexing
60	Not used		Specifies the PARDISO mode of operation: out-of-core (OOC) or in-core (InCore)
61	Not used		Total peak memory at analysis and factorization phases
62	Not used		Total double precision memory consumption at analysis and factorization phases
63	Not used		Total double precision memory consumption at factorization and solution phases