SRC/cunmtr.f(3)

✨ NAME ✨

okay so bestie, this is the Library Functions Manual page for SRC/cunmtr.f(3) — yes, the CUNMTR subroutine's page, and it's literally here to do complex unitary matrix things. 💅

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🌈 SYNOPSIS 🌈

🎀 Functions/Subroutines 🎀

subroutine cunmtr (side, uplo, trans, m, n, a, lda, tau, c, ldc, work,
    lwork, info)
    CUNMTR

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🦋 Function/Subroutine Documentation 🦋

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

🌸 Purpose 🌸

CUNMTR 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 CHETRD:

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 CHETRD;
  • = 'L': Lower triangle of A contains elementary reflectors from CHETRD.
• 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 array, dimension
  • (LDA,M) if SIDE = 'L'
  • (LDA,N) if SIDE = 'R'
  • The vectors which define the elementary reflectors, as returned by CHETRD.
• 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 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 CHETRD.
• C — C is COMPLEX 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 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 170 of file cunmtr.f.

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🧚 Author 🧚

Generated automatically by Doxygen for LAPACK from the source code.

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💖 that's the whole manual page, bestie. Signing off from LAPACK Version 3.12.0, page SRC/cunmtr.f(3) — periodt. 🎀