CGEMV(3)

💅 CGEMV(3) 💅 — your Library Functions Manual era ✨

okay so bestie, this is the page for CGEMV, and it is lowkey giving “linear algebra but make it a group chat.” 💖

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💖 NAME 💖

the file for this page is literally /home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/BLAS/SRC/cgemv.f — that's the whole NAME section, no cap. 🎀

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✨ SYNOPSIS ✨

🧚 Functions/Subroutines 🧚

subroutine CGEMV (trans, m, n, alpha, a, lda, x, incx, beta, y, incy)
           CGEMV

CGEMV — yes, that's the subroutine name, and it's iconic. 💅

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🦋 Function/Subroutine Documentation 🦋

subroutine CGEMV (character trans, integer m, integer n, complex alpha,
       complex, dimension(lda,*) a, integer lda, complex, dimension(*) x,
       integer incx, complex beta, complex, dimension(*) y, integer incy)

CGEMV — again, the name, because the manual says so. 🫶

🎀 Purpose 🎀

okay so CGEMV performs one of the matrix-vector operations — and here they are, exactly:

y := alpha*A*x + beta*y,   or   y := alpha*A**T*x + beta*y,   or

y := alpha*A**H*x + beta*y,

where alpha and beta are scalars, x and y are vectors and A is an m by n matrix. periodt. 💜

🌸 Parameters 🌸

• TRANS — TRANS is CHARACTER*1. On entry, TRANS specifies the operation to be performed as follows:
  • TRANS = 'N' or 'n' — y := alpha*A*x + beta*y.
  • TRANS = 'T' or 't' — y := alpha*A**T*x + beta*y.
  • TRANS = 'C' or 'c' — y := alpha*A**H*x + beta*y.
• M — M is INTEGER. On entry, M specifies the number of rows of the matrix A. M must be at least zero. 🍓
• N — N is INTEGER. On entry, N specifies the number of columns of the matrix A. N must be at least zero. 🍓
• ALPHA — ALPHA is COMPLEX. On entry, ALPHA specifies the scalar alpha. ✨
• A — A is COMPLEX array, dimension ( LDA, N ). Before entry, the leading m by n part of the array A must contain the matrix of coefficients. 💅
• LDA — LDA is INTEGER. On entry, LDA specifies the first dimension of A as declared in the calling (sub) program. LDA must be at least max( 1, m ). 🎀
• X — X is COMPLEX array, dimension at least ( 1 + ( n - 1 )*abs( INCX ) ) when TRANS = 'N' or 'n' and at least ( 1 + ( m - 1 )*abs( INCX ) ) otherwise. Before entry, the incremented array X must contain the vector x. 🌸
• INCX — INCX is INTEGER. On entry, INCX specifies the increment for the elements of X. INCX must not be zero. 🚨
• BETA — BETA is COMPLEX. On entry, BETA specifies the scalar beta. When BETA is supplied as zero then Y need not be set on input. 👑
• Y — Y is COMPLEX array, dimension at least ( 1 + ( m - 1 )*abs( INCY ) ) when TRANS = 'N' or 'n' and at least ( 1 + ( n - 1 )*abs( INCY ) ) otherwise. Before entry with BETA non-zero, the incremented array Y must contain the vector y. On exit, Y is overwritten by the updated vector y. If either m or n is zero, then Y not referenced and the function performs a quick return. 💖
• INCY — INCY is INTEGER. On entry, INCY specifies the increment for the elements of Y. INCY must not be zero. 🚨

🚨 real talk: INCX must not be zero, and INCY must not be zero. That's not a vibe suggestion, that's the manual. 💀

👑 Author 👑

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

⭐ Further Details ⭐

Level 2 Blas routine. The vector and matrix arguments are not referenced when N = 0, or M = 0

-- Written on 22-October-1986. Jack Dongarra, Argonne National Lab. Jeremy Du Croz, Nag Central Office. Sven Hammarling, Nag Central Office. Richard Hanson, Sandia National Labs.

Definition at line 159 of file cgemv.f. 📌

🌈 Author 🌈

Generated automatically by Doxygen for LAPACK from the source code. 🤖✨

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💖 okay bestie, that's the whole page — later, and remember: CGEMV ate and left no crumbs. 💖

💅 source/version sign-off: LAPACK Version 3.12.0, from /home/abui...SRC/cgemv.f(3). 🎀