SRC/strcon.f(3)

💅 SRC/strcon.f(3) 💅

okay bestie, this is the Library Functions Manual page for SRC/strcon.f, and it's all about the STRCON subroutine. Let's get into it. ✨

🌸 NAME 🌸

SRC/strcon.f — that's the page, and it's serving STRCON energy. 💖

✨ SYNOPSIS ✨

🧚 Functions/Subroutines 🧚

subroutine strcon (norm, uplo, diag, n, a, lda, rcond, work, iwork,
    info)
    STRCON

🫶 Function/Subroutine Documentation 🫶

🎀 subroutine strcon 🎀

subroutine strcon (character norm, character uplo, character diag, integer
    n, real, dimension( lda, * ) a, integer lda, real rcond, real,
    dimension( * ) work, integer, dimension( * ) iwork, integer info)
    STRCON

💖 Purpose 💖

okay so STRCON estimates the reciprocal of the condition number of a triangular matrix A, in either the 1-norm or the infinity-norm. No cap.

The norm of A is computed, and an estimate is obtained for norm(inv(A)), then the reciprocal of the condition number is computed as

RCOND = 1 / ( norm(A) * norm(inv(A)) ).

🎀 Parameters 🎀

• NORM — NORM is CHARACTER*1. It specifies whether the 1-norm condition number or the infinity-norm condition number is required:
  • = '1' or 'O': 1-norm;
  • = 'I': Infinity-norm.
• UPLO — UPLO is CHARACTER*1
  • = 'U': A is upper triangular;
  • = 'L': A is lower triangular.
• DIAG — DIAG is CHARACTER*1
  • = 'N': A is non-unit triangular;
  • = 'U': A is unit triangular.
• N — N is INTEGER. The order of the matrix A. N >= 0.
• A — A is REAL array, dimension (LDA,N). The triangular matrix A. If UPLO = 'U', the leading N-by-N upper triangular part of the array A contains the upper triangular matrix, and the strictly lower triangular part of A is not referenced. If UPLO = 'L', the leading N-by-N lower triangular part of the array A contains the lower triangular matrix, and the strictly upper triangular part of A is not referenced. If DIAG = 'U', the diagonal elements of A are also not referenced and are assumed to be 1.
• LDA — LDA is INTEGER. The leading dimension of the array A. LDA >= max(1,N).
• RCOND — RCOND is REAL. The reciprocal of the condition number of the matrix A, computed as RCOND = 1/(norm(A) * norm(inv(A))).
• WORK — WORK is REAL array, dimension (3*N).
• IWORK — IWORK is INTEGER array, dimension (N).
• INFO — INFO is INTEGER
  • = 0: successful exit
  • < 0: if INFO = -i, the i-th argument had an illegal value

👑 Author 👑

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

Definition at line 135 of file strcon.f.

🌈 Author 🌈

Generated automatically by Doxygen for LAPACK from the source code.

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mwah 💖 that's the whole page, bestie — source/version: LAPACK, Version 3.12.0; page: SRC/strcon.f(3). The original footer didn't give a date, so I'm not inventing one. periodt. 🫶