BLAS/SRC/zgemm.f(3)

💖 BLAS/SRC/zgemm.f(3) — Library Functions Manual realness

okay so bestie, welcome to the Library Functions Manual page for BLAS/SRC/zgemm.f. It's giving complex matrix multiplication, but make it BLAS Level 3. The file is literally the home of the zgemm subroutine, and she is iconic. 💅

✨ NAME

BLAS/SRC/zgemm.f — that's the file, and inside it lives zgemm, no cap.

🦋 SYNOPSIS

Functions/Subroutines

• subroutine zgemm (transa, transb, m, n, k, alpha, a, lda, b, ldb, beta, c, ldc) — ZGEMM

🎀 Function/Subroutine Documentation

subroutine zgemm (character transa, character transb, integer m, integer n,
    integer k, complex*16 alpha, complex*16, dimension(lda,*) a, integer
    lda, complex*16, dimension(ldb,*) b, integer ldb, complex*16 beta,
    complex*16, dimension(ldc,*) c, integer ldc)

ZGEMM — say hi to the main character 💅

Purpose

ZGEMM performs one of the matrix-matrix operations

C := alpha*op( A )*op( B ) + beta*C,

where op( X ) is one of

op( X ) = X   or   op( X ) = X**T   or   op( X ) = X**H,

alpha and beta are scalars, and A, B and C are matrices, with op( A ) an m by k matrix, op( B ) a k by n matrix and C an m by n matrix. Periodt. 🔥

Parameters

• TRANSA — TRANSA is CHARACTER*1. On entry, TRANSA specifies the form of op( A ) to be used in the matrix multiplication as follows:
  • TRANSA = 'N' or 'n', op( A ) = A.
  • TRANSA = 'T' or 't', op( A ) = A**T.
  • TRANSA = 'C' or 'c', op( A ) = A**H.
• TRANSB — TRANSB is CHARACTER*1. On entry, TRANSB specifies the form of op( B ) to be used in the matrix multiplication as follows:
  • TRANSB = 'N' or 'n', op( B ) = B.
  • TRANSB = 'T' or 't', op( B ) = B**T.
  • TRANSB = 'C' or 'c', op( B ) = B**H.
• M — M is INTEGER. On entry, M specifies the number of rows of the matrix op( A ) and of the matrix C. M must be at least zero.
• N — N is INTEGER. On entry, N specifies the number of columns of the matrix op( B ) and the number of columns of the matrix C. N must be at least zero.
• K — K is INTEGER. On entry, K specifies the number of columns of the matrix op( A ) and the number of rows of the matrix op( B ). K must be at least zero.
• ALPHA — ALPHA is COMPLEX*16. On entry, ALPHA specifies the scalar alpha.
• A — A is COMPLEX*16 array, dimension ( LDA, ka ), where ka is k when TRANSA = 'N' or 'n', and is m otherwise. Before entry with TRANSA = 'N' or 'n', the leading m by k part of the array A must contain the matrix A; otherwise the leading k by m part of the array A must contain the matrix A.
• LDA — LDA is INTEGER. On entry, LDA specifies the first dimension of A as declared in the calling (sub) program. When TRANSA = 'N' or 'n' then LDA must be at least max( 1, m ), otherwise LDA must be at least max( 1, k ).
• B — B is COMPLEX*16 array, dimension ( LDB, kb ), where kb is n when TRANSB = 'N' or 'n', and is k otherwise. Before entry with TRANSB = 'N' or 'n', the leading k by n part of the array B must contain the matrix B; otherwise the leading n by k part of the array B must contain the matrix B.
• LDB — LDB is INTEGER. On entry, LDB specifies the first dimension of B as declared in the calling (sub) program. When TRANSB = 'N' or 'n' then LDB must be at least max( 1, k ), otherwise LDB must be at least max( 1, n ).
• BETA — BETA is COMPLEX*16. On entry, BETA specifies the scalar beta. When BETA is supplied as zero then C need not be set on input.
• C — C is COMPLEX*16 array, dimension ( LDC, N ). Before entry, the leading m by n part of the array C must contain the matrix C, except when beta is zero, in which case C need not be set on entry. On exit, the array C is overwritten by the m by n matrix ( alpha*op( A )*op( B ) + beta*C ).
• LDC — LDC is INTEGER. On entry, LDC specifies the first dimension of C as declared in the calling (sub) program. LDC must be at least max( 1, m ).

Author

• Univ. of Tennessee
• Univ. of California Berkeley
• Univ. of Colorado Denver
• NAG Ltd.

Further Details

• Level 3 Blas routine.
• -- Written on 8-February-1989.
  • Jack Dongarra, Argonne National Laboratory.
  • Iain Duff, AERE Harwell.
  • Jeremy Du Croz, Numerical Algorithms Group Ltd.
  • Sven Hammarling, Numerical Algorithms Group Ltd.

Definition at line 186 of file zgemm.f.

Author

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and that's the whole page, bestie! Source/version check: LAPACK Version 3.12.0. The date slot isn't printed on this page, so I'm not inventing one 💅. Auto-generated by Doxygen for LAPACK from the source code. Byeee 🫶✨