ZHETRI2X(3)

💖 NAME 💖

okay bestie, welcome to ZHETRI2X(3) from the Library Functions Manual 🫶 — this is the page for the file /home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/SRC/zhetri2x.f. It’s giving very specific LAPACK energy, no cap.

💅 SYNOPSIS 💅

🦋 Functions/Subroutines 🦋

subroutine ZHETRI2X (uplo, n, a, lda, ipiv, work, nb, info)
           ZHETRI2X

🌈 Function/Subroutine Documentation 🌈

Here’s the full signature, exactly as the page says:

subroutine ZHETRI2X (character uplo, integer n, complex*16, dimension( lda,
       * ) a, integer lda, integer, dimension( * ) ipiv, complex*16, dimension(
       n+nb+1,* ) work, integer nb, integer info)
       ZHETRI2X

✨ Purpose ✨

Bestie, the purpose is literally this: ZHETRI2X computes the inverse of a COMPLEX*16 Hermitian indefinite matrix A using the factorization A = U*D*U**H or A = L*D*L**H computed by ZHETRF. That’s the whole vibe check 💫

🎀 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. It’s the order of the matrix A. N >= 0.

🦋 A 🦋

A is COMPLEX*16 array, dimension (LDA,N).

On entry, the NNB diagonal matrix D and the multipliers used to obtain the factor U or L as computed by ZHETRF.

On exit, if INFO = 0, the (symmetric) inverse of the original matrix. If UPLO = 'U', the upper triangular part of the inverse is formed and the part of A below the diagonal is not referenced; if UPLO = 'L' the lower triangular part of the inverse is formed and the part of A above the diagonal is not referenced.

🧚 LDA 🧚

LDA is INTEGER. It’s the leading dimension of the array A. LDA >= max(1,N).

💜 IPIV 💜

IPIV is INTEGER array, dimension (N). It holds details of the interchanges and the NNB structure of D as determined by ZHETRF.

🍓 WORK 🍓

WORK is COMPLEX*16 array, dimension (N+NB+1,NB+3).

🔥 NB 🔥

NB is INTEGER. Block size.

⭐ 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 119 of file zhetri2x.f.

🧚 Author 🧚

Generated automatically by Doxygen for LAPACK from the source code.

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Footer moment, bestie: LAPACK, Version 3.12.0, at /home/abui.../zhetri2x.f(3) — that’s the sign-off, mwah 💜✨