BLAS/SRC/dgemmtr.f(3)

NAME 💖

okay so this is the Library Functions Manual page for BLAS/SRC/dgemmtr.f — that's the file, bestie, and it's giving level-3 BLAS realness.

SYNOPSIS ✨

Functions/Subroutines 🫶

subroutine dgemmtr (uplo, transa, transb, n, k, alpha, a, lda, b, ldb,
    beta, c, ldc)

this one is called DGEMMTR and yes it's a subroutine, no cap.

Function/Subroutine Documentation 💅

subroutine dgemmtr signature 🌸

subroutine dgemmtr (character uplo, character transa, character transb,
    integer n, integer k, double precision alpha, double precision,
    dimension(lda,*) a, integer lda, double precision, dimension(ldb,*) b,
    integer ldb, double precision beta, double precision, dimension(ldc,*)
    c, integer ldc)

DGEMMTR is the main character here.

Purpose 🌸

DGEMMTR 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,

alpha and beta are scalars, and A, B and C are matrices, with op( A ) an n by k matrix, op( B ) a k by n matrix and C an n by n matrix. Thereby, the routine only accesses and updates the upper or lower triangular part of the result matrix C. This behaviour can be used if the resulting matrix C is known to be symmetric. iykyk — triangular only, bestie.

Parameters 🎀

• UPLO — UPLO is CHARACTER*1. On entry, UPLO specifies whether the lower or the upper triangular part of C is access and updated. UPLO = 'L' or 'l', the lower triangular part of C is used. UPLO = 'U' or 'u', the upper triangular part of C is used.
• 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**T.
• 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**T.
• N — N is INTEGER. On entry, N specifies the number of rows and columns of the matrix C, the number of columns of op(B) and the number of rows of op(A). 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 DOUBLE PRECISION. On entry, ALPHA specifies the scalar alpha.
• A — A is DOUBLE PRECISION array, dimension ( LDA, ka ), where ka is k when TRANSA = 'N' or 'n', and is n otherwise. Before entry with TRANSA = 'N' or 'n', the leading n 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, n ), otherwise LDA must be at least max( 1, k ).
• B — B is DOUBLE PRECISION 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 DOUBLE PRECISION. On entry, BETA specifies the scalar beta. When BETA is supplied as zero then C need not be set on input.
• C — C is DOUBLE PRECISION array, dimension ( LDC, N ). Before entry, the leading n 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 upper or lower triangular part of the matrix C is overwritten by the n 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, n ).

Author ✨

Martin Koehler

Further Details 💜

Level 3 Blas routine.

-- Written on 19-July-2023.
   Martin Koehler, MPI Magdeburg

Definition at line 189 of file dgemmtr.f. so that's where it lives in the source.

Author 🌈

Generated automatically by Doxygen for LAPACK from the source code. no notes, it's just Doxygen doing its thing.

---

sign-off time, bestie: this page is from LAPACK Version 3.12.0, for BLAS/SRC/dgemmtr.f(3) — periodt, slay, bye! 💅💖