Change language to:
English - Français - 日本語 - Русский

Please note that the recommended version of Scilab is 2024.1.0. This page might be outdated.
See the recommended documentation of this function

Ajuda do Scilab >> Interfaces com UMFPACK (sparse) > umf_lusolve

# umf_lusolve

solve a linear sparse system given the LU factors

### Calling Sequence

`[x] = umf_lusolve(LU_ptr, b [, st, A])`

### Arguments

LU_ptr

a pointer to umf lu factors (L,U,p,q,R)

b

a real or complex column vector or a matrix (multiple rhs)

st

(optional) a string "Ax=b" (default) or "Ax'=b" (to be written "Ax''=b" in scilab langage: a quote in a string must be doubled !)

A

(optional) the sparse square matrix corresponding to the LU factors (LU_ptr must be got with LU_ptr = umf_lufact(A))

x

a column vector or a matrix in case of multiple rhs ( x(:,i) is solution of A x(:,i) = b(:,i) or A'x(:,i) = b(:,i) )

### Description

This function must be used in conjonction with umf_lufact which computes the LU factors of a sparse matrix. The optional `st` argument lets us choose between the solving of Ax=b (general case) or of A'x=b (sometimes useful). If you give the 4th argument then iterative refinement will be also proceceed (as in umfpack) to give a better numerical solution.

### Examples

see the example section of umf_lufact

### See Also

• umfpack — solve sparse linear system
• umf_lufact — lu factorization of a sparse matrix
• umf_luget — retrieve lu factors at the Scilab level
• umf_ludel — utility function used with umf_lufact
• umf_luinfo — get information on LU factors
 Report an issue << umf_luinfo Interfaces com UMFPACK (sparse) umfpack >>

 Copyright (c) 2022-2024 (Dassault Systèmes)Copyright (c) 2017-2022 (ESI Group)Copyright (c) 2011-2017 (Scilab Enterprises)Copyright (c) 1989-2012 (INRIA)Copyright (c) 1989-2007 (ENPC)with contributors Last updated:Thu Oct 02 13:57:41 CEST 2014