DPTTRS(3)

🎀 DPTTRS(3) 🎀

Library Functions Manual energy, bestie. This page is for the DPTTRS subroutine, and both the header and footer show the truncated path /home/abui...RC/dpttrs.f(3). The NAME section is literally the source-file path below. 💅

🌸 NAME 🌸

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/SRC/dpttrs.f

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🦋 SYNOPSIS 🦋

✨ Functions/Subroutines ✨

• subroutine DPTTRS (n, nrhs, d, e, b, ldb, info) — DPTTRS

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💖 Function/Subroutine Documentation 💖

Here's the full typed signature, copied exactly because we do not play with code, periodt:

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

And yes, the label under it is just DPTTRS again — main character energy, no cap. 😌

🎯 Purpose 🎯

DPTTRS 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. Literally the whole plot. 💫

🧸 Parameters 🧸

• N — INTEGER. The order of the tridiagonal matrix A. Constraint: N >= 0.
• NRHS — INTEGER. The number of right hand sides, i.e., the number of columns of the matrix B. Constraint: NRHS >= 0.
• D — DOUBLE PRECISION array, dimension (N). The n diagonal elements of the diagonal matrix D from the L*D*L**T factorization of A. Yes, lower-case n in the original — not me, bestie. 🙈
• E — 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 — 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 — INTEGER. The leading dimension of the array B. Constraint: LDB >= max(1,N).
• INFO — INTEGER. = 0: successful exit. < 0: if INFO = -k, the k-th argument had an illegal value.

🫶 Quick vibe check: the constraints are N >= 0, NRHS >= 0, and LDB >= max(1,N). If INFO = -k, the k-th argument had an illegal value — that's the built-in callout, not me being dramatic. 💀

👑 Author 👑

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

📌 Definition at line 108 of file dpttrs.f. 📌

🧚 Author (Doxygen edition) 🧚

Generated automatically by Doxygen for LAPACK from the source code.

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That's the whole page, bestie — footer vibes say LAPACK Version 3.12.0 and the path /home/abui...RC/dpttrs.f(3). No date line is present in the footer, so that's the tea. 💅✨