Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

ID 766686
Date 6/24/2024
Public

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?gthrz

Gathers a sparse vector's elements into compressed form, replacing them by zeros.

Syntax

call sgthrz(nz, y, x, indx )

call dgthrz(nz, y, x, indx )

call cgthrz(nz, y, x, indx )

call zgthrz(nz, y, x, indx )

res = gthrz(x, indx, y)

Include Files

  • mkl.fi, blas.f90

Description

The ?gthrz routines gather the elements with indices specified by the array indx from a full-storage vector y into compressed form (nz, x, indx) and overwrite the gathered elements of y by zeros. Other elements of y are not referenced or modified (see also ?gthr).

Input Parameters

nz

INTEGER. The number of elements of y to be gathered.

indx

INTEGER. Specifies indices of elements to be gathered.

Array, size at least nz.

y

REAL for sgthrz

DOUBLE PRECISION for dgthrz

COMPLEX for cgthrz

DOUBLE COMPLEX for zgthrz

Array, size at least max(indx(i)).

Output Parameters

x

REAL for sgthrz

DOUBLE PRECISION for dgthrz

COMPLEX for cgthrz

DOUBLE COMPLEX for zgthrz

Array, size at least nz.

Contains the vector converted to the compressed form.

y

The updated vector y.

BLAS 95 Interface Notes

Routines in Fortran 95 interface have fewer arguments in the calling sequence than their FORTRAN 77 counterparts. For general conventions applied to skip redundant or reconstructible arguments, see BLAS 95 Interface Conventions.

Specific details for the routine gthrz interface are the following:

x

Holds the vector with the number of elements nz.

indx

Holds the vector with the number of elements nz.

y

Holds the vector with the number of elements nz.