SLANTR(3)

🌸 SLANTR(3) 🌸

okay so bestie, welcome to the SLANTR glow-up 💅 this one lives in the Library Functions Manual, and its whole entire address is literally right here — it's a Fortran source file, not a program you run, but we're vibing with its man page anyway:

/home/abui...RC/slantr.f(3)

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✨ NAME ✨

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

like... yes that's the whole NAME section, she's a file path and she's iconic for it 🎀

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🦋 SYNOPSIS 🦋

Functions/Subroutines

• real function SLANTR (norm, uplo, diag, m, n, a, lda, work) — lowkey the whole point: SLANTR hands you back the value of the 1-norm, or the Frobenius norm, or the infinity norm, or the element of largest absolute value of a trapezoidal or triangular matrix. no cap. 🔥

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👑 Function/Subroutine Documentation 👑

real function SLANTR (character norm, character uplo, character diag, integer m, integer n, real, dimension( lda, * ) a, integer lda, real, dimension( * ) work)

so literally what it says on the tin: SLANTR returns the value of the 1-norm, or the Frobenius norm, or the infinity norm, or the element of largest absolute value of a trapezoidal or triangular matrix. ate and left no crumbs 💖

🧚 Purpose

!>
!> SLANTR  returns the value of the one norm,  or the Frobenius norm, or
!> the  infinity norm,  or the  element of  largest absolute value  of a
!> trapezoidal or triangular matrix A.
!>

⭐ Returns

SLANTR 💫 and here's the whole menu of what she can give you, verbatim bestie:

!>
!>    SLANTR = ( 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.
!>

⚠️ real talk: max(abs(A(i,j))) is not a consistent matrix norm. that's just facts, don't come for her 🙈

🌈 Parameters

• NORM — is CHARACTER*1. it specifies the value to be returned in SLANTR, as described above. that's the whole vibe check right there 💅
• UPLO — is CHARACTER*1. specifies whether the matrix A is upper or lower trapezoidal:
  • = 'U': upper trapezoidal
  • = 'L': lower trapezoidal

and note that A is triangular instead of trapezoidal if M = N. iykyk 🦋

• DIAG — is CHARACTER*1. specifies whether or not the matrix A has unit diagonal:
  • = 'N': non-unit diagonal
  • = 'U': unit diagonal
• M — is INTEGER. the number of rows of the matrix A. M >= 0, and if UPLO = 'U', M <= N. when M = 0, SLANTR is set to zero. slay, respectful of the zero case ✨
• N — is INTEGER. the number of columns of the matrix A. N >= 0, and if UPLO = 'L', N <= M. when N = 0, SLANTR is set to zero. same energy, love that for her 💖
• A — is REAL array, dimension (LDA,N). the trapezoidal matrix A (A is triangular if M = N).
  • if UPLO = 'U', the leading m by n upper trapezoidal part of the array A contains the upper trapezoidal matrix, and the strictly lower triangular part of A is not referenced.
  • if UPLO = 'L', the leading m by n lower trapezoidal part of the array A contains the lower trapezoidal matrix, and the strictly upper triangular part of A is not referenced.
  • note that when DIAG = 'U', the diagonal elements of A are not referenced and are assumed to be one. assumed! don't check! she trusts you 🫶
• LDA — is INTEGER. the leading dimension of the array A. LDA >= max(M,1). periodt.
• WORK — is REAL array, dimension (MAX(1,LWORK)), where LWORK >= M when NORM = 'I'; otherwise, WORK is not referenced. so she only shows up for the infinity-norm shift 🔥

🎀 Author

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

definition at line 139 of file slantr.f. iconic line number ngl ⭐

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💜 Author 💜

Generated automatically by Doxygen for LAPACK from the source code. (yes she was literally born from a code generator, main character energy fr fr 💀✨)

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🌈 and that's the whole page bestie 🌈

cute little sign-off before you go: this gorgeous thing is LAPACK, Version 3.12.0, and it's filed under /home/abui...RC/slantr.f(3) — mwah, go forth and norm responsibly 💅💖