
sppsv.f(3) LAPACK sppsv.f(3)
NAME
sppsv.f 
SYNOPSIS
Functions/Subroutines
subroutine sppsv (UPLO, N, NRHS, AP, B, LDB, INFO)
SPPSV computes the solution to system of linear equations A * X = B for OTHER
matrices
Function/Subroutine Documentation
subroutine sppsv (characterUPLO, integerN, integerNRHS, real, dimension( * )AP, real,
dimension( ldb, * )B, integerLDB, integerINFO)
SPPSV computes the solution to system of linear equations A * X = B for OTHER matrices
Purpose:
SPPSV computes the solution to a real system of linear equations
A * X = B,
where A is an NbyN symmetric positive definite matrix stored in
packed format and X and B are NbyNRHS matrices.
The Cholesky decomposition is used to factor A as
A = U**T* U, if UPLO = 'U', or
A = L * L**T, if UPLO = 'L',
where U is an upper triangular matrix and L is a lower triangular
matrix. The factored form of A is then used to solve the system of
equations A * X = B.
Parameters:
UPLO
UPLO is CHARACTER*1
= 'U': Upper triangle of A is stored;
= 'L': Lower triangle of A is stored.
N
N is INTEGER
The number of linear equations, i.e., the order of the
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.
AP
AP is REAL array, dimension (N*(N+1)/2)
On entry, the upper or lower triangle of the symmetric matrix
A, packed columnwise in a linear array. The jth column of A
is stored in the array AP as follows:
if UPLO = 'U', AP(i + (j1)*j/2) = A(i,j) for 1<=i<=j;
if UPLO = 'L', AP(i + (j1)*(2nj)/2) = A(i,j) for j<=i<=n.
See below for further details.
On exit, if INFO = 0, the factor U or L from the Cholesky
factorization A = U**T*U or A = L*L**T, in the same storage
format as A.
B
B is REAL array, dimension (LDB,NRHS)
On entry, the NbyNRHS right hand side matrix B.
On exit, if INFO = 0, the NbyNRHS solution matrix X.
LDB
LDB is INTEGER
The leading dimension of the array B. LDB >= max(1,N).
INFO
INFO is INTEGER
= 0: successful exit
< 0: if INFO = i, the ith argument had an illegal value
> 0: if INFO = i, the leading minor of order i of A is not
positive definite, so the factorization could not be
completed, and the solution has not been computed.
Author:
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Date:
November 2011
Further Details:
The packed storage scheme is illustrated by the following example
when N = 4, UPLO = 'U':
Twodimensional storage of the symmetric matrix A:
a11 a12 a13 a14
a22 a23 a24
a33 a34 (aij = conjg(aji))
a44
Packed storage of the upper triangle of A:
AP = [ a11, a12, a22, a13, a23, a33, a14, a24, a34, a44 ]
Definition at line 145 of file sppsv.f.
Author
Generated automatically by Doxygen for LAPACK from the source code.
Version 3.4.2 Tue Sep 25 2012 sppsv.f(3) 
