SRC/zsycon_rook.f(3)

💖 NAME

SRC/zsycon_rook.f — the source-file page for this routine, straight out of the Library Functions Manual. 🫶

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✨ SYNOPSIS

🦋 Functions/Subroutines

subroutine zsycon_rook (uplo, n, a, lda, ipiv, anorm, rcond, work, info)

ZSYCON_ROOK

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🧚 Function/Subroutine Documentation

subroutine zsycon_rook (character uplo, integer n, complex*16, dimension(
    lda, * ) a, integer lda, integer, dimension( * ) ipiv, double precision
    anorm, double precision rcond, complex*16, dimension( * ) work, integer
    info)

ZSYCON_ROOK

🎀 Purpose

okay so bestie, here's the whole point: ZSYCON_ROOK estimates the reciprocal of the condition number (in the 1-norm) of a complex symmetric matrix A using the factorization A = U*D*U**T or A = L*D*L**T computed by ZSYTRF_ROOK.

An estimate is obtained for norm(inv(A)), and the reciprocal of the condition number is computed as RCOND = 1 / (ANORM * norm(inv(A))). ✨

🍓 Parameters

• UPLO — CHARACTER*1. Specifies whether the details of the factorization are stored as an upper or lower triangular matrix. = 'U': Upper triangular, form is A = U*D*U**T; = 'L': Lower triangular, form is A = L*D*L**T.
• N — INTEGER. The order of the matrix A. N >= 0.
• A — COMPLEX*16 array, dimension (LDA,N). The block diagonal matrix D and the multipliers used to obtain the factor U or L as computed by ZSYTRF_ROOK.
• LDA — INTEGER. The leading dimension of the array A. LDA >= max(1,N).
• IPIV — INTEGER array, dimension (N). Details of the interchanges and the block structure of D as determined by ZSYTRF_ROOK.
• ANORM — DOUBLE PRECISION. The 1-norm of the original matrix A.
• RCOND — DOUBLE PRECISION. The reciprocal of the condition number of the matrix A, computed as RCOND = 1/(ANORM * AINVNM), where AINVNM is an estimate of the 1-norm of inv(A) computed in this routine.
• WORK — COMPLEX*16 array, dimension (2*N).
• INFO — 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.

🌈 Contributors

• December 2016, Igor Kozachenko, Computer Science Division, University of California, Berkeley
• September 2007, Sven Hammarling, Nicholas J. Higham, Craig Lucas, School of Mathematics, University of Manchester

Definition at line 137 of file zsycon_rook.f.

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💜 Author

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xoxo bestie 💋 — footer tea: LAPACK Version 3.12.0, source page SRC/zsycon_rook.f(3). 🎀