SRC/zppcon.f(3)

💖 NAME 💖

okay so this page is SRC/zppcon.f(3), straight outta the Library Functions Manual — and it’s lowkey a whole baddie because it documents ZPPCON. periodt 💅

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✨ SYNOPSIS ✨

🦋 Functions/Subroutines 🦋

• subroutine zppcon (uplo, n, ap, anorm, rcond, work, rwork, info) — ZPPCON, the main character of this page 👑

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🌸 Function/Subroutine Documentation 🌸

🎀 subroutine zppcon 🎀

Here’s the full signature, bestie — keep it exact, no autocorrect energy:

   subroutine zppcon (character uplo, integer n, complex*16, dimension( * ) ap,
       double precision anorm, double precision rcond, complex*16, dimension( *
       ) work, double precision, dimension( * ) rwork, integer info)

ZPPCON

🎯 Purpose

ZPPCON estimates the reciprocal of the condition number (in the 1-norm) of a complex Hermitian positive definite packed matrix using the Cholesky factorization A = U**H*U or A = L*L**H computed by ZPPTRF.

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

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🧸 Parameters 🧸

• UPLO — UPLO is CHARACTER*1. It’s giving “which triangle are we storing?”:
  • = 'U': Upper triangle of A is stored;
  • = 'L': Lower triangle of A is stored.
• N — N is INTEGER. The order of the matrix A. N >= 0.
• AP — AP is COMPLEX*16 array, dimension (N*(N+1)/2). This is the triangular factor U or L from the Cholesky factorization A = U**H*U or A = L*L**H, packed columnwise in a linear array. The j-th column of U or L is stored in the array AP as follows:

if UPLO = 'U', AP(i + (j-1)*j/2) = U(i,j) for 1<=i<=j;
if UPLO = 'L', AP(i + (j-1)*(2n-j)/2) = L(i,j) for j<=i<=n.

• ANORM — ANORM is DOUBLE PRECISION. The 1-norm (or infinity-norm) of the Hermitian matrix A.
• RCOND — RCOND is 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 — WORK is COMPLEX*16 array, dimension (2*N).
• RWORK — RWORK is DOUBLE PRECISION array, dimension (N).
• INFO — INFO is INTEGER:
  • = 0: successful exit
  • < 0: if INFO = -i, the i-th argument had an illegal value

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👑 Author 👑

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

Definition at line 117 of file zppcon.f.

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👑 Author (the Doxygen one) 👑

Generated automatically by Doxygen for LAPACK from the source code.

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that’s the whole page, bestie — LAPACK Version 3.12.0, page SRC/zppcon.f(3), and yes, the footer energy is immaculate 💅✨🫶