dtpcon.f(3) LAPACK dtpcon.f(3)
subroutine dtpcon (NORM, UPLO, DIAG, N, AP, RCOND, WORK, IWORK, INFO)
subroutine dtpcon (characterNORM, characterUPLO, characterDIAG, integerN, double precision, dimension( * )AP, double precisionRCOND, double
precision, dimension( * )WORK, integer, dimension( * )IWORK, integerINFO)
DTPCON estimates the reciprocal of the condition number of a packed
triangular matrix A, in either the 1-norm or the infinity-norm.
The norm of A is computed and an estimate is obtained for
norm(inv(A)), then the reciprocal of the condition number is
RCOND = 1 / ( norm(A) * norm(inv(A)) ).
NORM is CHARACTER*1
Specifies whether the 1-norm condition number or the
infinity-norm condition number is required:
= '1' or 'O': 1-norm;
= 'I': Infinity-norm.
UPLO is CHARACTER*1
= 'U': A is upper triangular;
= 'L': A is lower triangular.
DIAG is CHARACTER*1
= 'N': A is non-unit triangular;
= 'U': A is unit triangular.
N is INTEGER
The order of the matrix A. N >= 0.
AP is DOUBLE PRECISION array, dimension (N*(N+1)/2)
The upper or lower triangular matrix A, packed columnwise in
a linear array. The j-th column of A is stored in the array
AP as follows:
if UPLO = 'U', AP(i + (j-1)*j/2) = A(i,j) for 1<=i<=j;
if UPLO = 'L', AP(i + (j-1)*(2n-j)/2) = A(i,j) for j<=i<=n.
If DIAG = 'U', the diagonal elements of A are not referenced
and are assumed to be 1.
RCOND is DOUBLE PRECISION
The reciprocal of the condition number of the matrix A,
computed as RCOND = 1/(norm(A) * norm(inv(A))).
WORK is DOUBLE PRECISION array, dimension (3*N)
IWORK is INTEGER array, dimension (N)
INFO is INTEGER
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
Definition at line 130 of file dtpcon.f.
Generated automatically by Doxygen for LAPACK from the source code.
Version 3.4.2 Tue Sep 25 2012 dtpcon.f(3)