Developer Reference for Intel® oneAPI Math Kernel Library for Fortran
?gthr
Gathers a full-storage sparse vector’s elements into compressed form.
Syntax
call sgthr ( nz, y, x, indx )
call dgthr ( nz, y, x, indx )
call cgthr ( nz, y, x, indx )
call zgthr ( nz, y, x, indx )
res = gthr ( x, indx, y )
Include Files
mkl.fi , mkl_blas.f90
Description
The ?gthr routines gather the specified elements of a full-storage sparse vector \(y\) into compressed form ( nz, x, indx). The routines reference only the elements of \(y\) whose indices are listed in the array \(indx\) :
\[x(i) = y(indx(i)) \text{, for } i=1,2,\dots,nz\]
Input Parameters
nz
INTEGER .
The number of elements in x and indx and the number of elements to be gathered from y.
indx
INTEGER.
Specifies the indices for the elements of x. Array, size at least nz .
y
REAL |
for sgthr |
DOUBLE PRECISION |
for dgthr |
COMPLEX |
for cgthr |
DOUBLE COMPLEX |
for zgthr |
Array, size at least \(\max(\text{indx}(i))\).
Output Parameters
x
REAL |
for sgthr |
DOUBLE |
for dgthr |
COMPLEX |
for cgthr |
DOUBLE COMPLEX |
for zgthr |
Array, size at least nz . Contains the vector converted to the compressed form.
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 gthr 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 .