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dpptri.f(3) LAPACK dpptri.f(3)

NAME

dpptri.f -

SYNOPSIS

Functions/Subroutines


subroutine dpptri (UPLO, N, AP, INFO)
 
DPPTRI

Function/Subroutine Documentation

subroutine dpptri (characterUPLO, integerN, double precision, dimension( * )AP, integerINFO)

DPPTRI
Purpose:
 DPPTRI computes the inverse of a real symmetric positive definite
 matrix A using the Cholesky factorization A = U**T*U or A = L*L**T
 computed by DPPTRF.
Parameters:
UPLO
          UPLO is CHARACTER*1
          = 'U':  Upper triangular factor is stored in AP;
          = 'L':  Lower triangular factor is stored in AP.
N
          N is INTEGER
          The order of the matrix A.  N >= 0.
AP
          AP is DOUBLE PRECISION array, dimension (N*(N+1)/2)
          On entry, the triangular factor U or L from the Cholesky
          factorization A = U**T*U or A = L*L**T, packed columnwise as
          a linear array.  The j-th column of U or L is stored in the
          array AP as follows:
          if UPLO = 'U', AP(i + (j-1)*j/2) = U(i,j) for 1<=i<=j;
          if UPLO = 'L', AP(i + (j-1)*(2n-j)/2) = L(i,j) for j<=i<=n.
On exit, the upper or lower triangle of the (symmetric) inverse of A, overwriting the input factor U or L.
INFO
          INFO is INTEGER
          = 0:  successful exit
          < 0:  if INFO = -i, the i-th argument had an illegal value
          > 0:  if INFO = i, the (i,i) element of the factor U or L is
                zero, and the inverse could not be computed.
Author:
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Date:
November 2011
Definition at line 94 of file dpptri.f.

Author

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