SRC/dpptrs.f(3)

📦
version 3.12.1 · 7 versions
, in arch rolling

💅 NAME 💅

SRC/dpptrs.f — okay so this is the manual page for the dpptrs routine, and yes bestie, it's a Fortran/LAPACK situation. 💖

✨ SYNOPSIS ✨

🌸 Functions/Subroutines 🌸

subroutine dpptrs (uplo, n, nrhs, ap, b, ldb, info)
    DPPTRS

🎀 Function/Subroutine Documentation 🎀

subroutine dpptrs (character uplo, integer n, integer nrhs, double precision, dimension( * ) ap, double precision, dimension( ldb, * ) b, integer ldb, integer info)
    DPPTRS

🦋 Purpose 🦋

Okay so the whole vibe of DPPTRS is: it solves a system of linear equations A*X = B with a symmetric positive definite matrix A in packed storage using the Cholesky factorization A = U**T*U or A = L*L**T computed by DPPTRF. The way that this routine just solves it is literally the main character energy of the page. 💅

🍓 Parameters 🍓

  • UPLO — UPLO is CHARACTER*1. = 'U': upper triangle of A is stored; = 'L': lower triangle of A is stored. Lowkey important, bestie.
  • N — N is INTEGER; it's the order of the matrix A. N >= 0.
  • NRHS — NRHS is INTEGER; the number of right hand sides, i.e., the number of columns of the matrix B. NRHS >= 0.
  • AP — AP is DOUBLE PRECISION array, dimension (N*(N+1)/2). It holds the triangular factor U or L from the Cholesky factorization A = U**T*U or A = L*L**T, packed columnwise in 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.
  • B — B is DOUBLE PRECISION array, dimension (LDB,NRHS). On entry, the right hand side matrix B. On exit, the solution matrix X. It's giving glow-up. ✨
  • LDB — LDB is INTEGER; the leading dimension of the array B. LDB >= max(1,N).
  • INFO — INFO is INTEGER.
    • = 0: successful exit 🎉
    • < 0: if INFO = -i, the i-th argument had an illegal value 😭

👑 Author 👑

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

Definition at line 107 of file dpptrs.f.

💖 Author 💖

Generated automatically by Doxygen for LAPACK from the source code.

Okay bestie, that's the whole page — LAPACK Version 3.12.0, SRC/dpptrs.f(3), mwah 💋✨

📦 where this page comes from