SRC/zunmtr.f(3)

NAME

SRC/zunmtr.f — okay bestie, this is the page for the ZUNMTR subroutine, and it lives in the Library Functions Manual. It’s giving “complex matrix, but make it couture” energy ✨

SYNOPSIS

Functions/Subroutines

• subroutine zunmtr (side, uplo, trans, m, n, a, lda, tau, c, ldc, work, lwork, info) — ZUNMTR

🦋 Function/Subroutine Documentation 🦋

🫶 subroutine zunmtr 🫶

subroutine zunmtr (character side, character uplo, character trans, integer m, integer n, complex*16, dimension( lda, * ) a, integer lda, complex*16, dimension( * ) tau, complex*16, dimension( ldc, * ) c, integer ldc, complex*16, dimension( * ) work, integer lwork, integer info)

ZUNMTR — okay so this is the main character subroutine, no cap.

✨ Purpose ✨

ZUNMTR overwrites the general complex M-by-N matrix C with:

                SIDE = 'L'     SIDE = 'R'
TRANS = 'N':      Q * C          C * Q
TRANS = 'C':      Q**H * C       C * Q**H

where Q is a complex unitary matrix of order nq, with nq = m if SIDE = 'L' and nq = n if SIDE = 'R'. Q is defined as the product of nq-1 elementary reflectors, as returned by ZHETRD:

if UPLO = 'U', Q = H(nq-1) . . . H(2) H(1);

if UPLO = 'L', Q = H(1) H(2) . . . H(nq-1).

🎀 Parameters 🎀

• SIDE — SIDE is CHARACTER*1
  • = 'L': apply Q or Q**H from the Left;
  • = 'R': apply Q or Q**H from the Right.
• UPLO — UPLO is CHARACTER*1
  • = 'U': Upper triangle of A contains elementary reflectors from ZHETRD;
  • = 'L': Lower triangle of A contains elementary reflectors from ZHETRD.
• TRANS — TRANS is CHARACTER*1
  • = 'N': No transpose, apply Q;
  • = 'C': Conjugate transpose, apply Q**H.
• M — M is INTEGER The number of rows of the matrix C. M >= 0.
• N — N is INTEGER The number of columns of the matrix C. N >= 0.
• A — A is COMPLEX*16 array, dimension (LDA,M) if SIDE = 'L' / (LDA,N) if SIDE = 'R'; the vectors which define the elementary reflectors, as returned by ZHETRD.
• LDA — LDA is INTEGER The leading dimension of the array A. LDA >= max(1,M) if SIDE = 'L'; LDA >= max(1,N) if SIDE = 'R'.
• TAU — TAU is COMPLEX*16 array, dimension (M-1) if SIDE = 'L' / (N-1) if SIDE = 'R'; TAU(i) must contain the scalar factor of the elementary reflector H(i), as returned by ZHETRD.
• C — C is COMPLEX*16 array, dimension (LDC,N) On entry, the M-by-N matrix C. On exit, C is overwritten by Q*C or Q**H*C or C*Q**H or C*Q.
• LDC — LDC is INTEGER The leading dimension of the array C. LDC >= max(1,M).
• WORK — WORK is COMPLEX*16 array, dimension (MAX(1,LWORK)) On exit, if INFO = 0, WORK(1) returns the optimal LWORK.
• LWORK — LWORK is INTEGER
  • The dimension of the array WORK.
  • If SIDE = 'L', LWORK >= max(1,N); if SIDE = 'R', LWORK >= max(1,M).
  • For optimum performance LWORK >= N*NB if SIDE = 'L', and LWORK >=M*NB if SIDE = 'R', where NB is the optimal blocksize.
  • If LWORK = -1, then a workspace query is assumed; the routine only calculates the optimal size of the WORK array, returns this value as the first entry of the WORK array, and no error message related to LWORK is issued by XERBLA.
• INFO — INFO is INTEGER
  • = 0: successful exit
  • < 0: if INFO = -i, the i-th argument had an illegal value

💜 Author 💜

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

Definition at line 169 of file zunmtr.f.

👑 Author 👑

Generated automatically by Doxygen for LAPACK from the source code.

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Okay bestie, that’s the whole page 💖 The footer tea is LAPACK Version 3.12.0 and source page SRC/zunmtr.f(3) — that’s the official sign-off, no cap 🫶✨