SRC/zptts2.f(3)

💖 SRC/zptts2.f(3) 💖

okay bestie, welcome to the SRC/zptts2.f page from the Library Functions Manual 🫶. This is the zptts2 subroutine’s moment to shine, and yes, it’s giving numerical linear algebra main character energy 💅.

✨ NAME ✨

SRC/zptts2.f — the page for zptts2, the tridiagonal-system solver with the L D LH factorization vibe 🦋

🎀 SYNOPSIS 🎀

🧚 Functions/Subroutines 🧚

• subroutine zptts2 (iuplo, n, nrhs, d, e, b, ldb) — ZPTTS2 solves a tridiagonal system of the form AX=B using the L D LH factorization computed by spttrf. Periodt.

🌸 FUNCTION/SUBROUTINE DOCUMENTATION 🌸

full signature, no cap

subroutine zptts2 (integer iuplo, integer n, integer nrhs, double precision,
       dimension( * ) d, complex*16, dimension( * ) e, complex*16, dimension(
       ldb, * ) b, integer ldb)

ZPTTS2 solves a tridiagonal system of the form AX=B using the L D LH factorization computed by spttrf. Iconic behavior only 🔥.

✨ Purpose ✨

Okay so ZPTTS2 solves a tridiagonal system of the form

A * X = B

using the factorization A = U**H *D*U or A = L*D*L**H computed by ZPTTRF. D is a diagonal matrix specified in the vector D, U (or L) is a unit bidiagonal matrix whose superdiagonal (subdiagonal) is specified in the vector E, and X and B are N by NRHS matrices. Obsessed with the math? yes, literally.

🌈 Parameters 🌈

• IUPLO — IUPLO is INTEGER. Specifies the form of the factorization and whether the vector E is the superdiagonal of the upper bidiagonal factor U or the subdiagonal of the lower bidiagonal factor L. The tea ☕:
  • = 1: A = U**H *D*U, E is the superdiagonal of U
  • = 0: A = L*D*L**H, E is the subdiagonal of L
• N — N is INTEGER. The order of the tridiagonal 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.
• D — D is DOUBLE PRECISION array, dimension (N). The n diagonal elements of the diagonal matrix D from the factorization A = U**H *D*U or A = L*D*L**H.
• E — E is COMPLEX*16 array, dimension (N-1). If IUPLO = 1, the (n-1) superdiagonal elements of the unit bidiagonal factor U from the factorization A = U**H*D*U. If IUPLO = 0, the (n-1) subdiagonal elements of the unit bidiagonal factor L from the factorization A = L*D*L**H.
• B — B is COMPLEX*16 array, dimension (LDB,NRHS). On entry, the right hand side vectors B for the system of linear equations. On exit, the solution vectors, X. Main character energy: goes in as B, comes out as X 💅.
• LDB — LDB is INTEGER. The leading dimension of the array B. LDB >= max(1,N).

👑 Author 👑

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

Definition at line 112 of file zptts2.f.

🫶 Author 🫶

Generated automatically by Doxygen for LAPACK from the source code.

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That’s the whole page, bestie. This icon is from LAPACK, Version 3.12.0, and the file is SRC/zptts2.f(3) 🌈💖🦋. Slay, and may your tridiagonal systems stay factored 🎀✨.