SUBROUTINE DGGHRD( COMPQ, COMPZ, N, ILO, IHI, A, LDA, B, LDB, Q, * LDQ, Z, LDZ, INFO) CHARACTER * 1 COMPQ, COMPZ INTEGER N, ILO, IHI, LDA, LDB, LDQ, LDZ, INFO DOUBLE PRECISION A(LDA,*), B(LDB,*), Q(LDQ,*), Z(LDZ,*) SUBROUTINE DGGHRD_64( COMPQ, COMPZ, N, ILO, IHI, A, LDA, B, LDB, Q, * LDQ, Z, LDZ, INFO) CHARACTER * 1 COMPQ, COMPZ INTEGER*8 N, ILO, IHI, LDA, LDB, LDQ, LDZ, INFO DOUBLE PRECISION A(LDA,*), B(LDB,*), Q(LDQ,*), Z(LDZ,*)
SUBROUTINE GGHRD( COMPQ, COMPZ, [N], ILO, IHI, A, [LDA], B, [LDB], * Q, [LDQ], Z, [LDZ], [INFO]) CHARACTER(LEN=1) :: COMPQ, COMPZ INTEGER :: N, ILO, IHI, LDA, LDB, LDQ, LDZ, INFO REAL(8), DIMENSION(:,:) :: A, B, Q, Z SUBROUTINE GGHRD_64( COMPQ, COMPZ, [N], ILO, IHI, A, [LDA], B, [LDB], * Q, [LDQ], Z, [LDZ], [INFO]) CHARACTER(LEN=1) :: COMPQ, COMPZ INTEGER(8) :: N, ILO, IHI, LDA, LDB, LDQ, LDZ, INFO REAL(8), DIMENSION(:,:) :: A, B, Q, Z
void dgghrd(char compq, char compz, int n, int ilo, int ihi, double *a, int lda, double *b, int ldb, double *q, int ldq, double *z, int ldz, int *info);
void dgghrd_64(char compq, char compz, long n, long ilo, long ihi, double *a, long lda, double *b, long ldb, double *q, long ldq, double *z, long ldz, long *info);
The orthogonal matrices Q and Z are determined as products of Givens rotations. They may either be formed explicitly, or they may be postmultiplied into input matrices Q1 and Z1, so that
1 * A * Z1' = (Q1*Q) * H * (Z1*Z)' 1 * B * Z1' = (Q1*Q) * T * (Z1*Z)'
If COMPQ='I': on entry, Q need not be set, and on exit it contains the orthogonal matrix Q, where Q' is the product of the Givens transformations which are applied to A and B on the left. If COMPQ='V': on entry, Q must contain an orthogonal matrix Q1, and on exit this is overwritten by Q1*Q.
If COMPZ='I': on entry, Z need not be set, and on exit it contains the orthogonal matrix Z, which is the product of the Givens transformations which are applied to A and B on the right. If COMPZ='V': on entry, Z must contain an orthogonal matrix Z1, and on exit this is overwritten by Z1*Z.