SRC/slange.f(3)

💅 SRC/slange.f — Library Functions Manual 💅

okay so bestie, this is the SRC/slange.f page from the Library Functions Manual, and it is all about SLANGE, the real function that hands you matrix norms. She is giving math-girlie main character energy, and we are obsessed. ✨

🌸 NAME 🌸

SRC/slange.f

That is literally the whole NAME section — just the file. But the function living here is SLANGE, and she is about to return a norm for you. 💖

🌸 SYNOPSIS 🌸

🎀 Functions/Subroutines 🎀

• real function slange (norm, m, n, a, lda, work) — SLANGE returns the value of the 1-norm, Frobenius norm, infinity-norm, or the largest absolute value of any element of a general rectangular matrix.

🧚 Function/Subroutine Documentation 🧚

🦋 the signature 🦋

real function slange (character norm, integer m, integer n, real, dimension(
       lda, * ) a, integer lda, real, dimension( * ) work)

SLANGE returns the value of the 1-norm, Frobenius norm, infinity-norm, or the largest absolute value of any element of a general rectangular matrix. Periodt.

💜 Purpose 💜

The purpose block is literally this, bestie:

!>
!> SLANGE  returns the value of the one norm,  or the Frobenius norm, or
!> the  infinity norm,  or the  element of  largest absolute value  of a
!> real matrix A.
!>

🔥 Returns 🔥

SLANGE returns this mapping — keep it exact, no cap:

!>
!>    SLANGE = ( max(abs(A(i,j))), NORM = 'M' or 'm'
!>             (
!>             ( norm1(A),         NORM = '1', 'O' or 'o'
!>             (
!>             ( normI(A),         NORM = 'I' or 'i'
!>             (
!>             ( normF(A),         NORM = 'F', 'f', 'E' or 'e'
!>
!> where  norm1  denotes the  one norm of a matrix (maximum column sum),
!> normI  denotes the  infinity norm  of a matrix  (maximum row sum) and
!> normF  denotes the  Frobenius norm of a matrix (square root of sum of
!> squares).  Note that  max(abs(A(i,j)))  is not a consistent matrix norm.
!>

🍓 Parameters 🍓

• NORM — NORM is CHARACTER*1 Specifies the value to be returned in SLANGE as described above.
• M — M is INTEGER The number of rows of the matrix A. M >= 0. When M = 0, SLANGE is set to zero.
• N — N is INTEGER The number of columns of the matrix A. N >= 0. When N = 0, SLANGE is set to zero.
• A — A is REAL array, dimension (LDA,N) The m by n matrix A.
• LDA — LDA is INTEGER The leading dimension of the array A. LDA >= max(M,1).
• WORK — WORK is REAL array, dimension (MAX(1,LWORK)), where LWORK >= M when NORM = 'I'; otherwise, WORK is not referenced.

👑 Author 👑

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

Definition at line 113 of file slange.f.

👑 Author 👑

Generated automatically by Doxygen for LAPACK from the source code.

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okay bye bestie — footer sign-off: LAPACK Version 3.12.0 · source SRC/slange.f(3) · mwah 💋💖