SRC/dptts2.f(3)

💖 NAME 💖

okay so bestie, we're in the Library Functions Manual and the main character of this page is SRC/dptts2.f — periodt. 💅

✨ SYNOPSIS ✨

Functions/Subroutines

• subroutine dptts2 (n, nrhs, d, e, b, ldb) — DPTTS2 solves a tridiagonal system of the form AX=B using the L D LH factorization computed by spttrf.

🦋 Function/Subroutine Documentation 🦋

subroutine dptts2 (integer n, integer nrhs, double precision, dimension( * )
    d, double precision, dimension( * ) e, double precision, dimension( ldb,
    * ) b, integer ldb)

DPTTS2 solves a tridiagonal system of the form AX=B using the L D LH factorization computed by spttrf.

🌸 Purpose 🌸

okay so DPTTS2 solves a tridiagonal system of the form

A * X = B

using the L*D*L**T factorization of A computed by DPTTRF. D is a diagonal matrix specified in the vector D, L is a unit bidiagonal matrix whose subdiagonal is specified in the vector E, and X and B are N by NRHS matrices. slay.

🎀 Parameters 🎀

N

N is INTEGER. It's 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 L*D*L**T factorization of A.

E

E is DOUBLE PRECISION array, dimension (N-1). The (n-1) subdiagonal elements of the unit bidiagonal factor L from the L*D*L**T factorization of A. E can also be regarded as the superdiagonal of the unit bidiagonal factor U from the factorization A = U**T*D*U.

B

B is DOUBLE PRECISION array, dimension (LDB,NRHS). On entry, the right hand side vectors B for the system of linear equations. On exit, the solution vectors, 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 101 of file dptts2.f.

👑 Author 👑

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