ZPPTRI(3)

💅 NAME

okay so bestie, this whole page is literally about one file:

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

that's it. that's the name. it's giving "the manpage just doxxed its own source path" 😭 but we move.

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✨ SYNOPSIS ✨

🫶 Functions/Subroutines

subroutine ZPPTRI (uplo, n, ap, info)

ZPPTRI — bestie's name is right there, no notes 💅

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🎀 Function/Subroutine Documentation 🎀

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

🌸 ZPPTRI 🌸

⭐ Purpose:

ok so picture this: 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 — and that factorization? yeah, it was computed by ZPPTRF. so not us. we're just the inverse girlies 🔥

🦋 Parameters

UPLO

• UPLO is CHARACTER*1
• = 'U': the upper triangular factor is stored in AP
• = 'L': the lower triangular factor is stored in AP

N

• N is INTEGER
• the order of the matrix A. and N >= 0, no cap 📏

AP

• AP is COMPLEX*16 array, dimension (N*(N+1)/2)
• on entry, it's 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, it holds the upper or lower triangle of the (Hermitian) inverse of A, and it overwrites the input factor U or L 👀 yes, it ate your input, that's the whole point

INFO

• INFO is INTEGER
• = 0: successful exit, slay ✨
• < 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 💀

no cap: if INFO comes back > 0 you literally do not have an inverse. go fix your matrix, bestie.

👑 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

this whole thing was generated automatically by Doxygen for LAPACK from the source code. not a human, just vibes and a doc generator 💫

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LAPACK — Version 3.12.0

and that's the page, babe. it's signed off with /home/abui...RC/zpptri.f(3) at the very bottom, which is honestly so real of it 🫶💖 stay packed, stay columnwise, mwah 🎀