dsytf2_rook - compute the factorization of a real symmetric indefinite matrix using the bounded Bunch-Kaufman ("rook") diagonal pivoting method (unblocked algorithm)
SUBROUTINE DSYTF2_ROOK(UPLO, N, A, LDA, IPIV, INFO) CHARACTER*1 UPLO INTEGER INFO, LDA, N INTEGER IPIV(*) DOUBLE PRECISION A(LDA,*) SUBROUTINE DSYTF2_ROOK_64(UPLO, N, A, LDA, IPIV, INFO) CHARACTER*1 UPLO INTEGER*8 INFO, LDA, N INTEGER*8 IPIV(*) DOUBLE PRECISION A(LDA,*) F95 INTERFACE SUBROUTINE SYTF2_ROOK(UPLO, N, A, LDA, IPIV, INFO) INTEGER :: N, LDA, INFO CHARACTER(LEN=1) :: UPLO INTEGER, DIMENSION(:) :: IPIV REAL(8), DIMENSION(:,:) :: A SUBROUTINE SYTF2_ROOK_64(UPLO, N, A, LDA, IPIV, INFO) INTEGER(8) :: N, LDA, INFO CHARACTER(LEN=1) :: UPLO INTEGER(8), DIMENSION(:) :: IPIV REAL(8), DIMENSION(:,:) :: A C INTERFACE #include <sunperf.h> void dsytf2_rook (char uplo, int n, double *a, int lda, int *ipiv, int *info); void dsytf2_rook_64 (char uplo, long n, double *a, long lda, long *ipiv, long *info);
Oracle Solaris Studio Performance Library dsytf2_rook(3P) NAME dsytf2_rook - compute the factorization of a real symmetric indefinite matrix using the bounded Bunch-Kaufman ("rook") diagonal pivoting method (unblocked algorithm) SYNOPSIS SUBROUTINE DSYTF2_ROOK(UPLO, N, A, LDA, IPIV, INFO) CHARACTER*1 UPLO INTEGER INFO, LDA, N INTEGER IPIV(*) DOUBLE PRECISION A(LDA,*) SUBROUTINE DSYTF2_ROOK_64(UPLO, N, A, LDA, IPIV, INFO) CHARACTER*1 UPLO INTEGER*8 INFO, LDA, N INTEGER*8 IPIV(*) DOUBLE PRECISION A(LDA,*) F95 INTERFACE SUBROUTINE SYTF2_ROOK(UPLO, N, A, LDA, IPIV, INFO) INTEGER :: N, LDA, INFO CHARACTER(LEN=1) :: UPLO INTEGER, DIMENSION(:) :: IPIV REAL(8), DIMENSION(:,:) :: A SUBROUTINE SYTF2_ROOK_64(UPLO, N, A, LDA, IPIV, INFO) INTEGER(8) :: N, LDA, INFO CHARACTER(LEN=1) :: UPLO INTEGER(8), DIMENSION(:) :: IPIV REAL(8), DIMENSION(:,:) :: A C INTERFACE #include <sunperf.h> void dsytf2_rook (char uplo, int n, double *a, int lda, int *ipiv, int *info); void dsytf2_rook_64 (char uplo, long n, double *a, long lda, long *ipiv, long *info); PURPOSE dsytf2_rook computes the factorization of a real symmetric matrix A using the bounded Bunch-Kaufman ("rook") diagonal pivoting method: A = U*D*U**T or A = L*D*L**T where U (or L) is a product of permutation and unit upper (lower) tri- angular matrices, U**T is the transpose of U, and D is symmetric and block diagonal with 1-by-1 and 2-by-2 diagonal blocks. This is the unblocked version of the algorithm, calling Level 2 BLAS. ARGUMENTS UPLO (input) UPLO is CHARACTER*1 Specifies whether the upper or lower triangular part of the symmetric matrix A is stored: = 'U': Upper triangular; = 'L': Lower triangular. N (input) N is INTEGER The order of the matrix A. N >= 0. A (input/output) A is DOUBLE PRECISION array, dimension (LDA,N) On entry, the symmetric matrix A. If UPLO = 'U', the leading n-by-n upper triangular part of A contains the upper triangular part of the matrix A, and the strictly lower triangular part of A is not referenced. If UPLO = 'L', the leading n-by-n lower triangular part of A contains the lower triangular part of the matrix A, and the strictly upper triangular part of A is not referenced. On exit, the block diagonal matrix D and the multipliers used to obtain the factor U or L (see below for further details). LDA (input) LDA is INTEGER The leading dimension of the array A. LDA >= max(1,N). IPIV (output) IPIV is INTEGER array, dimension (N) Details of the interchanges and the block structure of D. If UPLO = 'U': If IPIV(k) > 0, then rows and columns k and IPIV(k) were interchanged and D(k,k) is a 1-by-1 diagonal block. If IPIV(k) < 0 and IPIV(k-1) < 0, then rows and columns k and -IPIV(k) were interchanged and rows and columns k-1 and -IPIV(k-1) were inerchaged, D(k-1:k,k-1:k) is a 2-by-2 diago- nal block. If UPLO = 'L': If IPIV(k) > 0, then rows and columns k and IPIV(k) were interchanged and D(k,k) is a 1-by-1 diagonal block. If IPIV(k) < 0 and IPIV(k+1) < 0, then rows and columns k and -IPIV(k) were interchanged and rows and columns k+1 and -IPIV(k+1) were inerchaged, D(k:k+1,k:k+1) is a 2-by-2 diago- nal block. INFO (output) INFO is INTEGER = 0: successful exit; < 0: if INFO = -k, the k-th argument had an illegal value; > 0: if INFO = k, D(k,k) is exactly zero. The factorization has been completed, but the block diagonal matrix D is exactly singular, and division by zero will occur if it is used to solve a system of equations. 7 Nov 2015 dsytf2_rook(3P)