SRC/dlagtm.f(3)

💖 hey bestie, welcome to SRC/dlagtm.f(3) 💖

This page is straight out of the Library Functions Manual, and it's all about one subroutine: dlagtm. It's giving tridiagonal matrix-matrix product realness, and honestly? obsessed. 🎀

✨ NAME ✨

SRC/dlagtm.f — that's the name. That's the whole NAME section. Minimalist icon behavior. 💅

✨ SYNOPSIS ✨

🌈 Functions/Subroutines 🌈

subroutine dlagtm (trans, n, nrhs, alpha, dl, d, du, x, ldx, beta, b,
     ldb)

DLAGTM performs a matrix-matrix product of the form C = αAB+βC, where A is a tridiagonal matrix, B and C are rectangular matrices, and α and β are scalars, which may be 0, 1, or -1.

💅 Function/Subroutine Documentation 💅

🧚 subroutine dlagtm 🧚

subroutine dlagtm (character trans, integer n, integer nrhs, double
     precision alpha, double precision, dimension( * ) dl, double precision,
     dimension( * ) d, double precision, dimension( * ) du, double precision,
     dimension( ldx, * ) x, integer ldx, double precision beta, double
     precision, dimension( ldb, * ) b, integer ldb)

DLAGTM performs a matrix-matrix product of the form C = αAB+βC, where A is a tridiagonal matrix, B and C are rectangular matrices, and α and β are scalars, which may be 0, 1, or -1.

🎀 Purpose 🎀

DLAGTM performs a matrix-matrix product of the form

B := alpha * A * X + beta * B

where A is a tridiagonal matrix of order N, B and X are N by NRHS matrices, and alpha and beta are real scalars, each of which may be 0., 1., or -1.

🌸 Parameters 🌸

• TRANS — TRANS is CHARACTER*1. Specifies the operation applied to A.
  • = 'N': No transpose, B := alpha * A * X + beta * B
  • = 'T': Transpose, B := alpha * A'* X + beta * B
  • = 'C': Conjugate transpose = Transpose
• N — N is INTEGER. The order of the matrix A. N >= 0.
• NRHS — NRHS is INTEGER. The number of right hand sides, i.e., the number of columns of the matrices X and B.
• ALPHA — ALPHA is DOUBLE PRECISION. The scalar alpha. ALPHA must be 0., 1., or -1.; otherwise, it is assumed to be 0.
• DL — DL is DOUBLE PRECISION array, dimension (N-1). The (n-1) sub-diagonal elements of T.
• D — D is DOUBLE PRECISION array, dimension (N). The diagonal elements of T.
• DU — DU is DOUBLE PRECISION array, dimension (N-1). The (n-1) super-diagonal elements of T.
• X — X is DOUBLE PRECISION array, dimension (LDX,NRHS). The N by NRHS matrix X.
• LDX — LDX is INTEGER. The leading dimension of the array X. LDX >= max(N,1).
• BETA — BETA is DOUBLE PRECISION. The scalar beta. BETA must be 0., 1., or -1.; otherwise, it is assumed to be 1.
• B — B is DOUBLE PRECISION array, dimension (LDB,NRHS). On entry, the N by NRHS matrix B. On exit, B is overwritten by the matrix expression B := alpha * A * X + beta * B.
• LDB — LDB is INTEGER. The leading dimension of the array B. LDB >= max(N,1).

👑 Author 👑

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

📌 Definition 📌

Definition at line 143 of file dlagtm.f.

👑 Author (auto-generated footer edition) 👑

Generated automatically by Doxygen for LAPACK from the source code.

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okay that's the whole page, bestie 🫶 — sourced from SRC/dlagtm.f(3) and stamped LAPACK Version 3.12.0. The footer doesn't show a date, so I'm not inventing one 💅. periodt.