ZGEEQU(3)

💅 ZGEEQU(3) — Library Functions Manual 💅

🌸 NAME 🌸

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

Yep bestie, that's literally the path. No cap. 🫶

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✨ SYNOPSIS ✨

Functions/Subroutines

subroutine ZGEEQU (m, n, a, lda, r, c, rowcnd, colcnd, amax, info)

ZGEEQU

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🦋 Function/Subroutine Documentation 🦋

subroutine ZGEEQU (integer m, integer n, complex*16, dimension( lda, * ) a, integer lda, double precision, dimension( * ) r, double precision, dimension( * ) c, double precision rowcnd, double precision colcnd, double precision amax, integer info)

ZGEEQU

Purpose

Okay so ZGEEQU computes row and column scalings intended to equilibrate an M-by-N matrix A and reduce its condition number. R returns the row scale factors, and C returns the column scale factors — chosen to try to make the largest element in each row and column of the matrix B with elements B(i,j)=R(i)*A(i,j)*C(j) have absolute value 1.

R(i) and C(j) are restricted to be between SMLNUM = smallest safe number and BIGNUM = largest safe number. Use of these scaling factors is not guaranteed to reduce the condition number of A, but it works well in practice. Periodt. 💅

Parameters

• M — M is INTEGER. The number of rows of the matrix A. M >= 0.
• N — N is INTEGER. The number of columns of the matrix A. N >= 0.
• A — A is COMPLEX*16 array, dimension (LDA,N). The M-by-N matrix whose equilibration factors are to be computed.
• LDA — LDA is INTEGER. The leading dimension of the array A. LDA >= max(1,M).
• R — R is DOUBLE PRECISION array, dimension (M). If INFO = 0 or INFO > M, R contains the row scale factors for A.
• C — C is DOUBLE PRECISION array, dimension (N). If INFO = 0, C contains the column scale factors for A.
• ROWCND — ROWCND is DOUBLE PRECISION. If INFO = 0 or INFO > M, ROWCND contains the ratio of the smallest R(i) to the largest R(i). If ROWCND >= 0.1 and AMAX is neither too large nor too small, it is not worth scaling by R.
• COLCND — COLCND is DOUBLE PRECISION. If INFO = 0, COLCND contains the ratio of the smallest C(i) to the largest C(i). If COLCND >= 0.1, it is not worth scaling by C.
• AMAX — AMAX is DOUBLE PRECISION. Absolute value of largest matrix element. If AMAX is very close to overflow or very close to underflow, the matrix should be scaled.
• INFO — INFO is INTEGER. Here's the tea:
  • = 0: successful exit
  • < 0: if INFO = -i, the i-th argument had an illegal value
  • > 0: if INFO = i, and i is
    • <= M: the i-th row of A is exactly zero
    • > M: the (i-M)-th column of A is exactly zero

Author

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

Definition at line 138 of file zgeequ.f.

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💖 Author 💖

Generated automatically by Doxygen for LAPACK from the source code.

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And that's the vibe check, bestie 💫 — this page is from LAPACK, Version 3.12.0, and the footer path is /home/abui...RC/zgeequ.f(3). The original footer doesn't show a separate date, so I'm not inventing one — periodt. Mwah 💋