?gamx2d

Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

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ID 766686

Date 7/13/2023

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?gamx2d

Performs element-wise absolute value maximization.

Syntax

call igamx2d( icontxt, scope, top, m, n, a, lda, ra, ca, rcflag, rdest, cdest )

call sgamx2d( icontxt, scope, top, m, n, a, lda, ra, ca, rcflag, rdest, cdest )

call dgamx2d( icontxt, scope, top, m, n, a, lda, ra, ca, rcflag, rdest, cdest )

call cgamx2d( icontxt, scope, top, m, n, a, lda, ra, ca, rcflag, rdest, cdest )

call zgamx2d( icontxt, scope, top, m, n, a, lda, ra, ca, rcflag, rdest, cdest )

Input Parameters

icontxt	INTEGER. Integer handle that indicates the context.
scope	CHARACTER*1. Indicates what scope the combine should proceed on. Limited to ROW, COLUMN, or ALL.
top	CHARACTER*1. Communication pattern to use during the combine operation.
m	INTEGER. The number of matrix rows to be combined.
n	INTEGER. The number of matrix columns to be combined.
a	TYPE array `(lda, n)`. Matrix to be compared with to produce the maximum.
lda	INTEGER. The leading dimension of the matrix `A`, that is, the distance between two successive elements in a matrix row.
rcflag	INTEGER. If rcflag = -1, the arrays `ra` and `ca` are not referenced and need not exist. Otherwise, rcflag indicates the leading dimension of these arrays, and so must be ≥ m.
rdest	INTEGER. The process row coordinate of the process that should receive the result. If rdest or cdest = -1, all processes within the indicated scope receive the answer.
cdest	INTEGER. The process column coordinate of the process that should receive the result. If rdest or cdest = -1, all processes within the indicated scope receive the answer.

Output Parameters

TYPE array (lda, n). Contains the result if this process is selected to receive the answer, or intermediate results if the process is not selected to receive the result.

INTEGER array (rcflag, n).

If rcflag = -1, this array will not be referenced, and need not exist. Otherwise, it is an integer array (of size at least rcflag x n) indicating the row index of the process that provided the maximum. If the calling process is not selected to receive the result, this array will contain intermediate (useless) results.

INTEGER array (rcflag, n).

Description

This routine performs element-wise absolute value maximization, that is, each element of matrix A is compared with the corresponding element of the other process's matrices. Note that the value of A is returned, but the absolute value is used to determine the maximum (the 1-norm is used for complex numbers). Combines may be globally-blocking, so they must be programmed as if no process returns until all have called the routine.

Parent topic: BLACS Combine Operations

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Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

?gamx2d

Syntax

Input Parameters

Output Parameters

Description

See Also