SRC/zpptri.f(3)

💖 SRC/zpptri.f 💖

okay bestie, welcome to the Library Functions Manual glow-up for SRC/zpptri.f — this page is lowkey iconic and we're gonna read it together, fr fr. ✨

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🌸 NAME 🌸

SRC/zpptri.f — that's the name, periodt. 💅

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✨ SYNOPSIS ✨

🦋 Functions/Subroutines 🦋

subroutine zpptri (uplo, n, ap, info)
    ZPPTRI

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💅 Function/Subroutine Documentation 💅

🎀 subroutine zpptri 🎀

subroutine zpptri (character uplo, integer n, complex*16, dimension( * ) ap,
    integer info)
    ZPPTRI

💖 Purpose 💖

okay so ZPPTRI computes the inverse of a complex Hermitian positive definite matrix A using the Cholesky factorization A = U**H*U or A = L*L**H computed by ZPPTRF. no cap, that's the whole purpose. 🫶

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🍓 Parameters 🍓

UPLO is CHARACTER*1.

• = 'U': Upper triangular factor is stored in AP;
• = 'L': Lower triangular factor is stored in AP.

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

AP is COMPLEX*16 array, dimension (N*(N+1)/2).

On entry, the triangular factor U or L from the Cholesky factorization A = U**H*U or A = L*L**H, packed columnwise as 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.

On exit, the upper or lower triangle of the (Hermitian) inverse of A, overwriting the input factor U or L. bestie, it literally overwrites it. 💀

INFO is INTEGER.

• = 0: successful exit
• < 0: if INFO = -i, the i-th argument had an illegal value
• > 0: if INFO = i, the (i,i) element of the factor U or L is zero, and the inverse could not be computed.

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👑 Author 👑

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

Definition at line 92 of file zpptri.f.

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🧚 Author 🧚

Generated automatically by Doxygen for LAPACK from the source code.

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Sign-off: LAPACK, Version 3.12.0, SRC/zpptri.f(3) — that's the source/version footer, bestie, and the vibe is immaculate. 💖✨🦋