CHPTRI(3)

CHPTRI(3) 💅✨

okay bestie, welcome to a Library Functions Manual moment ✨ This is the CHPTRI(3) page, and the manual-name path energy up top is /home/abui...RC/chptri.f(3) — we’re folding that in near the top instead of copying the header line, because we’re cute and accurate. 🎀

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NAME 💖

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

That’s the whole NAME, bestie. Yes, it’s a path. Slay. 🫶

SYNOPSIS ✨

Functions/Subroutines 🌸

subroutine CHPTRI (uplo, n, ap, ipiv, work, info)
    CHPTRI

• subroutine CHPTRI (uplo, n, ap, ipiv, work, info) — the callable subroutine, looking iconic.
• CHPTRI — yes, it’s also listed as itself. Main character energy only. 👑

Function/Subroutine Documentation 🦋

subroutine CHPTRI (character uplo, integer n, complex, dimension( * ) ap,
       integer, dimension( * ) ipiv, complex, dimension( * ) work, integer
       info)

CHPTRI — again, the function/subroutine name, doing the absolute most. 💜

Purpose 💜

CHPTRI computes the inverse of a complex Hermitian indefinite matrix A in packed storage using the factorization A = U*D*U**H or A = L*D*L**H computed by CHPTRF.

Parameters 🎀

UPLO

UPLO is CHARACTER*1. It 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**H;
• = 'L': Lower triangular, form is A = L*D*L**H.

N

N is INTEGER. The order of the matrix A. N >= 0.

AP

AP is COMPLEX array, dimension (N*(N+1)/2).

On entry, the block diagonal matrix D and the multipliers used to obtain the factor U or L as computed by CHPTRF, stored as a packed triangular matrix.

On exit, if INFO = 0, the (Hermitian) inverse of the original matrix, stored as a packed triangular matrix. The j-th column of inv(A) is stored in the array AP as follows:

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

IPIV

IPIV is INTEGER array, dimension (N). Details of the interchanges and the block structure of D as determined by CHPTRF.

WORK

WORK is COMPLEX array, dimension (N).

INFO

INFO is INTEGER.

• = 0: successful exit
• < 0: if INFO = -i, the i-th argument had an illegal value
• > 0: if INFO = i, D(i,i) = 0; the matrix is singular and its inverse could not be computed.

Author 📝

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

Definition at line 108 of file chptri.f.

Author 🤖

Generated automatically by Doxygen for LAPACK from the source code.

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🌈 Cute little sign-off: this page is LAPACK Version 3.12.0, footer source /home/abui...RC/chptri.f(3) — the printed footer doesn’t give a date, bestie — and these docs were generated automatically by Doxygen for LAPACK from the source code. Mwah 💋✨