SRC/cpttrf.f(3)

📦
version 3.12.1 · 7 versions
, in arch rolling

🌸 NAME 🌸

SRC/cpttrf.f — from the Library Functions Manual, bestie. This is the page for the CPTTRF subroutine, and yes, it’s giving major linear-algebra main character energy. 💅✨

🎀 SYNOPSIS 🎀

💖 Functions/Subroutines 💖

subroutine cpttrf (n, d, e, info)
    CPTTRF

🦋 Function/Subroutine Documentation 🦋

subroutine cpttrf (integer n, real, dimension( * ) d, complex, dimension( * ) e, integer info)
    CPTTRF

CPTTRF is literally the icon of this page. 🫶

🌟 Purpose 🌟

okay so bestie, here’s the tea: CPTTRF computes the L*D*L**H factorization of a complex Hermitian positive definite tridiagonal matrix A. The factorization may also be regarded as having the form A = U**H *D*U. No cap. ✨

🍓 Parameters 🍓

N

N is INTEGER. It’s the order of the matrix A, and N >= 0. Periodt. 👑

D

D is REAL array, dimension (N). On entry, it holds the n diagonal elements of the tridiagonal matrix A. On exit, it holds the n diagonal elements of the diagonal matrix D from the L*D*L**H factorization of A. She’s doing a whole before-and-after glow-up. 💖

E

E is COMPLEX array, dimension (N-1). On entry, it holds the (n-1) subdiagonal elements of the tridiagonal matrix A. On exit, it holds the (n-1) subdiagonal elements of the unit bidiagonal factor L from the L*D*L**H factorization of A. E can also be regarded as the superdiagonal of the unit bidiagonal factor U from the U**H *D*U factorization of A. Versatile? Obsessed. 🦋

INFO

INFO is INTEGER.

  • = 0 — successful exit. slay. ✅
  • < 0 — if INFO = -k, the k-th argument had an illegal value. rude, but noted. 😭
  • > 0 — if INFO = k, the leading principal minor of order k is not positive; if k < N, the factorization could not be completed, while if k = N, the factorization was completed, but D(N) <= 0. 💀

👑 Author 👑

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

💜 Author 💜

Generated automatically by Doxygen for LAPACK from the source code.

⭐ Definition at line 91 of file cpttrf.f. ⭐

And that’s the whole vibe check, bestie. 💖✨

💖 LAPACK, Version 3.12.0 — this lil’ page lives at SRC/cpttrf.f(3) 💖

📦 where this page comes from