SRC/dpptri.f(3)

💖 NAME 💖

SRC/dpptri.f — okay bestie, this is the page for SRC/dpptri.f(3), and the manual name is Library Functions Manual. The whole page is about dpptri, a Fortran subroutine that does the inverse thing via Cholesky. Let's go 💅

✨ SYNOPSIS ✨

Functions/Subroutines

subroutine dpptri (uplo, n, ap, info)
    DPPTRI

That's the short version, bestie: function/subroutine energy, dpptri, args uplo, n, ap, info. ✨

👑 Function/Subroutine Documentation 👑

subroutine dpptri (character uplo, integer n, double precision, dimension( *
    ) ap, integer info)
    DPPTRI

🎯 Purpose 🎯

DPPTRI computes the inverse of a real symmetric positive definite matrix A using the Cholesky factorization A = U**T*U or A = L*L**T computed by DPPTRF. That's the whole plot, no cap. 💖

🧾 Parameters 🧾

• UPLO — UPLO is CHARACTER*1.
  • = 'U': Upper triangular factor is stored in AP;
  • = 'L': Lower triangular factor is stored in AP.
• N — N is INTEGER. The order of the matrix A. N >= 0.
• AP — AP is DOUBLE PRECISION array, dimension (N*(N+1)/2). On entry, the triangular factor U or L from the Cholesky factorization A = U**T*U or A = L*L**T, 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 (symmetric) inverse of A, overwriting the input factor U or L. 🫶

• INFO — 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.

👑 Author 👑

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

📍 Definition at line 📍

Definition at line 92 of file dpptri.f.

🌟 Author 🌟

Generated automatically by Doxygen for LAPACK from the source code.

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cute sign-off: sending you the footer vibe — this is LAPACK Version 3.12.0, page SRC/dpptri.f(3). The footer didn't show a date, so we're not making one up, bestie. 💅✨