SRC/sorgql.f(3)

🩷 SRC/sorgql.f(3) 🩷

From the Library Functions Manual — yup, that's the manual name folded right in, bestie. This whole page is the SORGQL subroutine from LAPACK. 🫶

✨ NAME ✨

SRC/sorgql.f

🌸 SYNOPSIS 🌸

🧚 Functions/Subroutines 🧚

• subroutine sorgql (m, n, k, a, lda, tau, work, lwork, info) — SORGQL

💅 Function/Subroutine Documentation 💅

🌟 subroutine sorgql 🌟

subroutine sorgql (integer m, integer n, integer k, real, dimension( lda, *
       ) a, integer lda, real, dimension( * ) tau, real, dimension( * ) work,
       integer lwork, integer info)
       SORGQL

🦋 Purpose 🦋

Okay so SORGQL generates an M-by-N real matrix Q with orthonormal columns. Q is defined as the last N columns of a product of K elementary reflectors of order M:

Q  =  H(k) . . . H(2) H(1)

...as returned by SGEQLF. Periodt. 💅

🎀 Parameters 🎀

• M — INTEGER, the number of rows of the matrix Q. M >= 0.
• N — INTEGER, the number of columns of the matrix Q. M >= N >= 0.
• K — INTEGER, the number of elementary reflectors whose product defines the matrix Q. N >= K >= 0.
• A — REAL array, dimension (LDA,N). On entry, the (n-k+i)-th column must contain the vector which defines the elementary reflector H(i), for i = 1,2,...,k, as returned by SGEQLF in the last k columns of its array argument A. On exit, it's the M-by-N matrix Q.
• LDA — INTEGER, the first dimension of the array A. LDA >= max(1,M).
• TAU — REAL array, dimension (K). TAU(i) must contain the scalar factor of the elementary reflector H(i), as returned by SGEQLF.
• WORK — REAL array, dimension (MAX(1,LWORK)). On exit, if INFO = 0, WORK(1) returns the optimal LWORK.
• LWORK — INTEGER, the dimension of the array WORK. LWORK >= max(1,N). For optimum performance, LWORK >= N*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 — INTEGER. = 0: successful exit. < 0: if INFO = -i, the i-th argument has an illegal value.

👑 Author 👑

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

Definition at line 127 of file sorgql.f.

🌈 Author 🌈

Generated automatically by Doxygen for LAPACK from the source code.

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💖 That's the whole page, bestie: LAPACK, Version 3.12.0, page SRC/sorgql.f(3). Byeee, go slay some orthonormal columns 💅✨