LAPACK
3.4.2
LAPACK: Linear Algebra PACKage

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Functions/Subroutines  
subroutine  dspcon (UPLO, N, AP, IPIV, ANORM, RCOND, WORK, IWORK, INFO) 
DSPCON 
subroutine dspcon  (  character  UPLO, 
integer  N,  
double precision, dimension( * )  AP,  
integer, dimension( * )  IPIV,  
double precision  ANORM,  
double precision  RCOND,  
double precision, dimension( * )  WORK,  
integer, dimension( * )  IWORK,  
integer  INFO  
) 
DSPCON
Download DSPCON + dependencies [TGZ] [ZIP] [TXT]DSPCON estimates the reciprocal of the condition number (in the 1norm) of a real symmetric packed matrix A using the factorization A = U*D*U**T or A = L*D*L**T computed by DSPTRF. An estimate is obtained for norm(inv(A)), and the reciprocal of the condition number is computed as RCOND = 1 / (ANORM * norm(inv(A))).
[in]  UPLO  UPLO is CHARACTER*1 Specifies whether the details of the factorization are stored as an upper or lower triangular matrix. = 'U': Upper triangular, form is A = U*D*U**T; = 'L': Lower triangular, form is A = L*D*L**T. 
[in]  N  N is INTEGER The order of the matrix A. N >= 0. 
[in]  AP  AP is DOUBLE PRECISION array, dimension (N*(N+1)/2) The block diagonal matrix D and the multipliers used to obtain the factor U or L as computed by DSPTRF, stored as a packed triangular matrix. 
[in]  IPIV  IPIV is INTEGER array, dimension (N) Details of the interchanges and the block structure of D as determined by DSPTRF. 
[in]  ANORM  ANORM is DOUBLE PRECISION The 1norm of the original matrix A. 
[out]  RCOND  RCOND is DOUBLE PRECISION The reciprocal of the condition number of the matrix A, computed as RCOND = 1/(ANORM * AINVNM), where AINVNM is an estimate of the 1norm of inv(A) computed in this routine. 
[out]  WORK  WORK is DOUBLE PRECISION array, dimension (2*N) 
[out]  IWORK  IWORK is INTEGER array, dimension (N) 
[out]  INFO  INFO is INTEGER = 0: successful exit < 0: if INFO = i, the ith argument had an illegal value 
Definition at line 125 of file dspcon.f.