DPPCON(3)

💖 NAME 💖

okay bestie, the manual name is DPPCON(3) and it's from the Library Functions Manual — the file this page is all about is:

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

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✨ SYNOPSIS ✨

🧚 Functions/Subroutines

       subroutine DPPCON (uplo, n, ap, anorm, rcond, work, iwork, info)
           DPPCON

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🫶 Function/Subroutine Documentation 🫶

   subroutine DPPCON (character uplo, integer n, double precision, dimension( *
       ) ap, double precision anorm, double precision rcond, double precision,
       dimension( * ) work, integer, dimension( * ) iwork, integer info)

DPPCON

🎯 Purpose

DPPCON estimates the reciprocal of the condition number (in the 1-norm) of a real symmetric positive definite packed matrix using the Cholesky factorization A = U**T*U or A = L*L**T computed by DPPTRF.

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 — UPLO is CHARACTER*1; = '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 DOUBLE PRECISION array, dimension (N*(N+1)/2); the triangular factor U or L from the Cholesky factorization A = U**T*U or A = L*L**T, 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 symmetric 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 DOUBLE PRECISION 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 117 of file dppcon.f.

🧚 Author

Generated automatically by Doxygen for LAPACK from the source code.

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okay that's the whole page, bestie — source/version footer tea: LAPACK Version 3.12.0, path /home/abui...RC/dppcon.f(3). There's no date printed in this footer, so no invented date energy here — bye bestie 💖🫶💅