BLAS/SRC/strsm.f(3)

🎀 NAME 🎀

BLAS/SRC/strsm.f — that's the name, bestie, and this page is from the Library Functions Manual, specifically the BLAS/SRC/strsm.f(3) page. 💅

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✨ SYNOPSIS ✨

🫶 Functions/Subroutines 🫶

       subroutine strsm (side, uplo, transa, diag, m, n, alpha, a, lda, b, ldb)
           STRSM

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💖 Function/Subroutine Documentation 💖

   subroutine strsm (character side, character uplo, character transa,
       character diag, integer m, integer n, real alpha, real, dimension(lda,*)
       a, integer lda, real, dimension(ldb,*) b, integer ldb)
       STRSM

🦋 Purpose 🦋

Okay so STRSM solves one of these matrix equations, no cap:

op( A )*X = alpha*B,   or   X*op( A ) = alpha*B,

where alpha is a scalar, X and B are m by n matrices, A is a unit, or non-unit, upper or lower triangular matrix, and op( A ) is one of:

op( A ) = A   or   op( A ) = A**T.

The matrix X is overwritten on B. That's the whole plot, periodt. 🫶

🌸 Parameters 🌸

• SIDE — CHARACTER*1. On entry, SIDE says whether op( A ) sits on the left or the right of X, like this:
  • SIDE = 'L' or 'l' → op( A )*X = alpha*B.
  • SIDE = 'R' or 'r' → X*op( A ) = alpha*B.
• UPLO — CHARACTER*1. On entry, UPLO tells you if A is upper or lower triangular:
  • UPLO = 'U' or 'u' → A is an upper triangular matrix.
  • UPLO = 'L' or 'l' → A is a lower triangular matrix.
• TRANSA — CHARACTER*1. On entry, TRANSA chooses the form of op( A ) used in the matrix multiplication:
  • TRANSA = 'N' or 'n' → op( A ) = A.
  • TRANSA = 'T' or 't' → op( A ) = A**T.
  • TRANSA = 'C' or 'c' → op( A ) = A**T.
• DIAG — CHARACTER*1. On entry, DIAG says whether A is unit triangular or not:
  • DIAG = 'U' or 'u' → A is assumed to be unit triangular.
  • DIAG = 'N' or 'n' → A is not assumed to be unit triangular.
• M — INTEGER. On entry, M specifies the number of rows of B. M must be at least zero. 🍓
• N — INTEGER. On entry, N specifies the number of columns of B. N must be at least zero. 🍓
• ALPHA — REAL. On entry, ALPHA specifies the scalar alpha. When alpha is zero, then A is not referenced and B need not be set before entry. obsessed with a parameter that lets you skip setup, honestly. ✨
• A — REAL array, dimension ( LDA, k ), where k is m when SIDE = 'L' or 'l', and k is n when SIDE = 'R' or 'r'.
  • Before entry with UPLO = 'U' or 'u', the leading k by k upper triangular part of the array A must contain the upper triangular matrix, and the strictly lower triangular part of A is not referenced.
  • Before entry with UPLO = 'L' or 'l', the leading k by k lower triangular part of the array A must contain the lower triangular matrix, and the strictly upper triangular part of A is not referenced.
  • Note that when DIAG = 'U' or 'u', the diagonal elements of A are not referenced either, but are assumed to be unity. iconic shortcut behavior tbh.
• LDA — INTEGER. On entry, LDA specifies the first dimension of A as declared in the calling (sub) program. When SIDE = 'L' or 'l' then LDA must be at least max( 1, m ); when SIDE = 'R' or 'r' then LDA must be at least max( 1, n ).
• B — REAL array, dimension ( LDB, N ). Before entry, the leading m by n part of the array B must contain the right-hand side matrix B, and on exit is overwritten by the solution matrix X. bye original B, hello solution X. 💅
• LDB — INTEGER. On entry, LDB specifies the first dimension of B as declared in the calling (sub) program. LDB 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 ⭐

Definition at line 180 of file strsm.f. 🫶

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💜 Author 💜

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Okay bestie, that's the whole BLAS/SRC/strsm.f(3) page, and the footer vibe is LAPACK, Version 3.12.0, page BLAS/SRC/strsm.f(3). Byeee 💖✨🎀