DORGTR(3)

💅 DORGTR(3) 💅

okay so bestie, welcome to DORGTR(3) — it's the Library Functions Manual page for /home/abui...RC/dorgtr.f(3). grab a lil snack, we're doing Fortran LAPACK things and honestly? iconic. 🎀

✨ NAME ✨

the source file in question is literally:

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/SRC/dorgtr.f

🌸 SYNOPSIS 🌸

Functions/Subroutines

• subroutine DORGTR (uplo, n, a, lda, tau, work, lwork, info) — DORGTR. that's the whole call, and yes DORGTR is the main character of this page. 💅

🦋 Function/Subroutine Documentation 🦋

subroutine DORGTR (character uplo, integer n, double precision, dimension(
       lda, * ) a, integer lda, double precision, dimension( * ) tau, double
       precision, dimension( * ) work, integer lwork, integer info)
       DORGTR

Purpose 💖

okay bestie, DORGTR generates a real orthogonal matrix Q and that queen is defined as the product of n-1 elementary reflectors of order N, exactly as returned by DSYTRD:

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

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

Parameters 🎀

• UPLO — UPLO is CHARACTER*1
  • = 'U': Upper triangle of A contains elementary reflectors from DSYTRD;
  • = 'L': Lower triangle of A contains elementary reflectors from DSYTRD.
• N — N is INTEGER. the order of the matrix Q. N >= 0. 🦋
• A — A is DOUBLE PRECISION array, dimension (LDA,N).
  • on entry, the vectors which define the elementary reflectors, as returned by DSYTRD.
  • on exit, the N-by-N orthogonal matrix Q.
• LDA — LDA is INTEGER. the leading dimension of the array A. LDA >= max(1,N).
• TAU — TAU is DOUBLE PRECISION array, dimension (N-1). TAU(i) must contain the scalar factor of the elementary reflector H(i), as returned by DSYTRD.
• WORK — WORK is DOUBLE PRECISION 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. LWORK >= max(1,N-1).
  • for optimum performance LWORK >= (N-1)*NB, 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 122 of file dorgtr.f. ✨

🌀 Author 🌀

Generated automatically by Doxygen for LAPACK from the source code. — automatic queen behavior, no cap. 💖

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okay that's the whole page, bestie. xoxo, the footer flex is LAPACK, Version 3.12.0, and /home/abui...RC/dorgtr.f(3) — no date printed here, just vibes and version numbers, mwah 💋✨