SRC/dgesv.f(3)

📦
version 3.12.1 · 7 versions
, in arch rolling

💖 NAME 💖

SRC/dgesv.f — bestie, this is the manual page for the LAPACK routine dgesv, from the Library Functions Manual 💅

✨ SYNOPSIS ✨

🎀 Functions/Subroutines 🎀

subroutine dgesv (n, nrhs, a, lda, ipiv, b, ldb, info)

🦋 Function/Subroutine Documentation 🦋

subroutine dgesv (integer n, integer nrhs, double precision, dimension( lda, * ) a, integer lda, integer, dimension( * ) ipiv, double precision, dimension( ldb, * ) b, integer ldb, integer info)

🌸 Purpose 🌸

okay so real talk: DGESV computes the solution to a real system of linear equations, and the whole vibe is:

A * X = B,

where A is an N-by-N matrix and X and B are N-by-NRHS matrices. iconic linear algebra behavior, no cap 💅

The LU decomposition with partial pivoting and row interchanges is used to factor A as:

A = P * L * U,

where P is a permutation matrix, L is unit lower triangular, and U is upper triangular. Then the factored form of A is used to solve the system of equations A * X = B. literally the whole glow-up of factor once, solve with it ✨

👑 Parameters 👑

  • N — N is INTEGER. it’s the number of linear equations, i.e., the order of the matrix A. N >= 0. bestie, zero is allowed, keep it cute 🫶
  • NRHS — NRHS is INTEGER. it’s the number of right hand sides, i.e., the number of columns of the matrix B. NRHS >= 0. yes, zero is valid here too 💖
  • A — A is DOUBLE PRECISION array, dimension (LDA,N). on entry, it’s the N-by-N coefficient matrix A. on exit, it holds the factors L and U from the factorization A = P*L*U; the unit diagonal elements of L are not stored. she’s transformed, periodt 💅
  • LDA — LDA is INTEGER. the leading dimension of the array A. LDA >= max(1,N). do not skip this check, i’m begging 😭
  • IPIV — IPIV is INTEGER array, dimension (N). these are the pivot indices that define the permutation matrix P; row i of the matrix was interchanged with row IPIV(i). the receipts of which rows got swapped, iykyk 🌈
  • B — B is DOUBLE PRECISION array, dimension (LDB,NRHS). on entry, it’s the N-by-NRHS matrix of right hand side matrix B. on exit, if INFO = 0, it’s the N-by-NRHS solution matrix X. she goes from right-hand-side to answer key 💖
  • LDB — LDB is INTEGER. the leading dimension of the array B. LDB >= max(1,N). another leading-dimension moment, respect it 🎀
  • INFO — INFO is INTEGER.
    • = 0: successful exit 🎉
    • < 0: if INFO = -i, the i-th argument had an illegal value 💀
    • > 0: if INFO = i, U(i,i) is exactly zero. the factorization has been completed, but the factor U is exactly singular, so the solution could not be computed. not her finest moment, but the math said what it said 😭

💜 Author 💜

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

Definition at line 123 of file dgesv.f. slay, line 123, main character energy 🔥

🌟 Author 🌟

Generated automatically by Doxygen for LAPACK from the source code. yes bestie, the robots made the docs cute 🧚

LAPACK · Version 3.12.0 · SRC/dgesv.f(3) — that’s the sign-off, mwah 💋✨

📦 where this page comes from