Parallel Engineering and Scientific Subroutine Library for AIX Version 2 Release 3: Guide and Reference

PDSPINIT--Initializes a General Sparse Matrix

This sparse utility subroutine initializes the local part of a general sparse matrix A.

Syntax

On Entry

as

See On Return.

ia1

See On Return.

ia2

See On Return.

infoa

is an array, referred to as INFOA, providing more information about the general sparse matrix A. You must specify INFOA(1) through INFOA(3), as follows:

• INFOA(1) is the length of the array AS, where: INFOA(1) >= max(2,nnze).
• INFOA(2) is the length of the array IA1, where: INFOA(2) >= max(3,(nnze+N_ROW)).
• INFOA(3) is the length of the array IA2, where: INFOA(3) >= max(3,(nnze+N_COL)).
• INFOA(4) through INFOA(30) are reserved for internal use.

nnze is the number of non-zero elements (including duplicate coefficients) in the local part of the global general sparse matrix A.

Specified as: an array of length 30, containing fullword integers.

desc_a

is the array descriptor for a global general sparse matrix A that is produced on a preceding call to PADINIT.

Specified as: an array of length DLEN, containing fullword integers.

On Return

as

is the local part, containing some internal values that are initialized by Parallel ESSL, of the global general sparse matrix A.

Scope: local

Returned as: a one-dimensional array of (at least) length INFOA(1), containing long-precision real numbers.

ia1

is the local part, containing some internal values that are initialized by Parallel ESSL, of the sparse matrix indices.

Scope: local

Returned as: a one-dimensional array of (at least) length INFOA(2), containing fullword integers.

ia2

is the local part, containing some internal values that are initialized by Parallel ESSL, of the sparse matrix indices.

Scope: local

Returned as: a one-dimensional array of (at least) length INFOA(3), containing fullword integers.

infoa

is the array INFOA updated with some internal values that are set by Parallel ESSL.

Returned as: an array of length 30, containing fullword integers.

desc_a

is the updated array descriptor for the global general sparse matrix A.

Returned as: an array of length DLEN, containing fullword integers.

Notes and Coding Rules

1. Before you call this subroutine, you must have called PADINIT.
2. For more details about N_ROW, N_COL, and other elements of desc_a, see Table 28.
3. For details about some of the elements stored in infoa, see Table 27.

Error Conditions

Computational Errors

None

Resource Errors

None.

Input-Argument and Miscellaneous Errors

Stage 1:  

1. The BLACS context is invalid.

Stage 2:  

1. This subroutine was called from outside the process grid.

Stage 3:  

1. The process grid is not np × 1.
2. INFOA(1) < 2; that is, the size of AS < 2
3. INFOA(2) < 3; that is, the size of IA1 < 3
4. INFOA(3) < 3; that is, the size of IA2 < 3