SPPTRI(3)

🌸 NAME 🌸

SPPTRI(3) — yes bestie, this is the LAPACK Library Functions Manual entry, and the file path is literally /home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/SRC/spptri.f. That path is long enough to need its own group chat, but that's what the NAME section says. 💅

✨ SYNOPSIS ✨

Under Functions/Subroutines, we've got:

subroutine SPPTRI (uplo, n, ap, info)
    SPPTRI

And the full signature:

subroutine SPPTRI (character uplo, integer n, real, dimension( * ) ap,
     integer info)

🦋 Function/Subroutine Documentation 🦋

💖 SPPTRI 💖

🌟 Purpose

SPPTRI 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 SPPTRF.

🎀 Parameters

• UPLO — CHARACTER*1
  • = 'U': Upper triangular factor is stored in AP;
  • = 'L': Lower triangular factor is stored in AP.
• N — INTEGER
  • The order of the matrix A. N >= 0.
• AP — REAL 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 — 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 92 of file spptri.f.

💜 Author 💜

Generated automatically by Doxygen for LAPACK from the source code.

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And that's the whole page, bestie. Cute little sign-off: this one is tagged LAPACK Version 3.12.0, and the footer path is /home/abui...RC/spptri.f(3) 🫶✨