SRC/slaqge.f(3)

✨ NAME ✨

SRC/slaqge.f — ok bestie, this page is from the Library Functions Manual, and it’s all about the slaqge Fortran subroutine. 💖

✨ SYNOPSIS ✨

Functions/Subroutines

subroutine slaqge (m, n, a, lda, r, c, rowcnd, colcnd, amax, equed)

SLAQGE scales a general rectangular matrix, using row and column scaling factors computed by sgeequ. slay. ✨

🌸 Function/Subroutine Documentation 🌸

subroutine slaqge (integer m, integer n, real, dimension( lda, * ) a,
    integer lda, real, dimension( * ) r, real, dimension( * ) c, real
    rowcnd, real colcnd, real amax, character equed)

SLAQGE scales a general rectangular matrix, using row and column scaling factors computed by sgeequ.

🎀 Purpose 🎀

SLAQGE equilibrates a general M by N matrix A using the row and column scaling factors in the vectors R and C. No cap, that’s the whole point. 💅

🎀 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 REAL array, dimension (LDA,N). On entry, the M by N matrix A. On exit, the equilibrated matrix. See EQUED for the form of the equilibrated matrix. 🦋
• LDA — LDA is INTEGER; the leading dimension of the array A. LDA >= max(M,1).
• R — R is REAL array, dimension (M); the row scale factors for A.
• C — C is REAL array, dimension (N); the column scale factors for A.
• ROWCND — ROWCND is REAL; ratio of the smallest R(i) to the largest R(i).
• COLCND — COLCND is REAL; ratio of the smallest C(i) to the largest C(i).
• AMAX — AMAX is REAL; absolute value of largest matrix entry.
• EQUED — EQUED is CHARACTER*1; specifies the form of equilibration that was done:
  • = 'N': No equilibration
  • = 'R': Row equilibration, i.e., A has been premultiplied by diag(R).
  • = 'C': Column equilibration, i.e., A has been postmultiplied by diag(C).
  • = 'B': Both row and column equilibration, i.e., A has been replaced by diag(R) * A * diag(C).

🧚 Internal Parameters 🧚

• THRESH is a threshold value used to decide if row or column scaling should be done based on the ratio of the row or column scaling factors. If ROWCND < THRESH, row scaling is done, and if COLCND < THRESH, column scaling is done.
• LARGE and SMALL are threshold values used to decide if row scaling should be done based on the absolute size of the largest matrix element. If AMAX > LARGE or AMAX < SMALL, row scaling is done.

👑 Author 👑

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

Definition at line 140 of file slaqge.f.

👑 Author 👑

Generated automatically by Doxygen for LAPACK from the source code.

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okay that’s the page bestie 💖 — it’s LAPACK Version 3.12.0, source SRC/slaqge.f(3). go off, matrix-equilibration icon. ✨👑