dpttrf - compute the L*D*L' factorization of a real symmetric positive definite tridiagonal matrix A
SUBROUTINE DPTTRF(N, D, E, INFO) INTEGER N, INFO DOUBLE PRECISION D(*), E(*) SUBROUTINE DPTTRF_64(N, D, E, INFO) INTEGER*8 N, INFO DOUBLE PRECISION D(*), E(*) F95 INTERFACE SUBROUTINE PTTRF(N, D, E, INFO) INTEGER :: N, INFO REAL(8), DIMENSION(:) :: D, E SUBROUTINE PTTRF_64(N, D, E, INFO) INTEGER(8) :: N, INFO REAL(8), DIMENSION(:) :: D, E C INTERFACE #include <sunperf.h> void dpttrf(int n, double *d, double *e, int *info); void dpttrf_64(long n, double *d, double *e, long *info);
Oracle Solaris Studio Performance Library dpttrf(3P) NAME dpttrf - compute the L*D*L' factorization of a real symmetric positive definite tridiagonal matrix A SYNOPSIS SUBROUTINE DPTTRF(N, D, E, INFO) INTEGER N, INFO DOUBLE PRECISION D(*), E(*) SUBROUTINE DPTTRF_64(N, D, E, INFO) INTEGER*8 N, INFO DOUBLE PRECISION D(*), E(*) F95 INTERFACE SUBROUTINE PTTRF(N, D, E, INFO) INTEGER :: N, INFO REAL(8), DIMENSION(:) :: D, E SUBROUTINE PTTRF_64(N, D, E, INFO) INTEGER(8) :: N, INFO REAL(8), DIMENSION(:) :: D, E C INTERFACE #include <sunperf.h> void dpttrf(int n, double *d, double *e, int *info); void dpttrf_64(long n, double *d, double *e, long *info); PURPOSE dpttrf computes the L*D*L' factorization of a real symmetric positive definite tridiagonal matrix A. The factorization may also be regarded as having the form A = U'*D*U. ARGUMENTS N (input) The order of the matrix A. N >= 0. D (input/output) On entry, the n diagonal elements of the tridiagonal matrix A. On exit, the n diagonal elements of the diagonal matrix D from the L*D*L' factorization of A. E (input/output) On entry, the (n-1) subdiagonal elements of the tridiagonal matrix A. On exit, the (n-1) subdiagonal elements of the unit bidiagonal factor L from the L*D*L' factorization of A. E can also be regarded as the superdiagonal of the unit bidi- agonal factor U from the U'*D*U factorization of A. INFO (output) = 0: successful exit < 0: if INFO = -k, the k-th argument had an illegal value > 0: if INFO = k, the leading minor of order k is not posi- tive definite; if k < N, the factorization could not be com- pleted, while if k = N, the factorization was completed, but D(N) = 0. 7 Nov 2015 dpttrf(3P)