?gemm_pack

Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

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ID 766686

Date 3/31/2023

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?gemm_pack

Performs scaling and packing of the matrix into the previously allocated buffer.

Syntax

call sgemm_pack (identifier, trans, m, n, k, alpha, src, ld, dest)

call dgemm_pack (identifier, trans, m, n, k, alpha, src, ld, dest)

Include Files

mkl.fi

Description

The ?gemm_pack routine is one of a set of related routines that enable use of an internal packed storage. Call ?gemm_pack after you allocate a buffer whose size is given by ?gemm_pack_get_size. The ?gemm_pack routine scales the identified matrix by alpha and packs it into the buffer allocated previously.

NOTE:

Do not copy the packed matrix to a different address because the internal implementation depends on the alignment of internally-stored metadata.

The ?gemm_pack routine performs this operation:

dest := alpha*op(src) as part of the computation C := alpha*op(A)*op(B) + beta*C

where:

op(X) is one of the operations op(X) = X, op(X) = X^T, or op(X) = X^H,
alpha and beta are scalars,
src is a matrix,
A , B, and C are matrices
op(src) is an m-by-k matrix if identifier = 'A' or 'a',
op(src) is a k-by-n matrix if identifier = 'B' or 'b',
dest is an internal packed storage buffer.

NOTE:

For best performance, use the same number of threads for packing and for computing.

If packing for both A and B matrices, you must use the same number of threads for packing A as for packing B.

Input Parameters

identifier

CHARACTER*1. Specifies which matrix is to be packed:

If identifier = 'A' or 'a', the routine allocates storage to pack matrix A.

If identifier = 'B' or 'b', the routine allocates storage to pack matrix B.

trans

CHARACTER*1. Specifies the form of op(src) used in the packing:

If trans = 'N' or 'n' op(src) = src.

If trans = 'T' or 't' op(src) = src^T.

If trans = 'C' or 'c' op(src) = src^H.

m

INTEGER. Specifies the number of rows of the matrix op(A) and of the matrix C. The value of m must be at least zero.

n

INTEGER. Specifies the number of columns of the matrix op(B) and the number of columns of the matrix C. The value of n must be at least zero.

k

INTEGER. Specifies the number of columns of the matrix op(A) and the number of rows of the matrix op(B). The value of k must be at least zero.

alpha

REAL for sgemm_pack

DOUBLE PRECISION for dgemm_pack

Specifies the scalar alpha.

src

REAL for sgemm_pack

DOUBLE PRECISION for dgemm_pack

Array:

trans = 'N' or 'n'

trans = 'T', 't', 'C', or 'c'

identifier = 'A' or 'a'

Size ld*k.

Before entry, the leading m-by-k part of the array src must contain the matrix A.

Size ld*m.

Before entry, the leading k-by-m part of the array src must contain the matrix A.

identifier = 'B' or 'b'

Size ld*n.

Before entry, the leading k-by-n part of the array src must contain the matrix B.

Size ld*k.

Before entry, the leading n-by-k part of the array src must contain the matrix B.

ld

INTEGER. Specifies the leading dimension of src as declared in the calling (sub)program.

	trans = `'N'` or `'n'`	trans = `'T'`, `'t'`, `'C'`, or `'c'`
identifier = `'A'` or `'a'`	ld must be at least `max(1, m)`.	ld must be at least `max(1, k)`.
identifier = `'B'` or `'b'`	ld must be at least `max(1, k)`.	ld must be at least `max(1, n)`.

dest

POINTER.

Scaled and packed internal storage buffer.

Output Parameters

dest	Overwritten by the matrix `alpha*op(src)`.

Parent topic: BLAS-like Extensions

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?gemm_pack

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