Subroutine */
| 25704 | } /* ztrevc_ */ |
| 25705 | |
| 25706 | /* Subroutine */ int ztrexc_(char *compq, integer *n, doublecomplex *t, |
| 25707 | integer *ldt, doublecomplex *q, integer *ldq, integer *ifst, integer * |
| 25708 | ilst, integer *info) |
| 25709 | { |
| 25710 | /* System generated locals */ |
| 25711 | integer q_dim1, q_offset, t_dim1, t_offset, i__1, i__2, i__3; |
| 25712 | doublecomplex z__1; |
| 25713 | |
| 25714 | /* Local variables */ |
| 25715 | static integer k, m1, m2, m3; |
| 25716 | static doublereal cs; |
| 25717 | static doublecomplex t11, t22, sn, temp; |
| 25718 | extern /* Subroutine */ int zrot_(integer *, doublecomplex *, integer *, |
| 25719 | doublecomplex *, integer *, doublereal *, doublecomplex *); |
| 25720 | extern logical lsame_(char *, char *); |
| 25721 | static logical wantq; |
| 25722 | extern /* Subroutine */ int xerbla_(char *, integer *), zlartg_( |
| 25723 | doublecomplex *, doublecomplex *, doublereal *, doublecomplex *, |
| 25724 | doublecomplex *); |
| 25725 | |
| 25726 | |
| 25727 | /* |
| 25728 | -- LAPACK routine (version 3.2) -- |
| 25729 | -- LAPACK is a software package provided by Univ. of Tennessee, -- |
| 25730 | -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- |
| 25731 | November 2006 |
| 25732 | |
| 25733 | |
| 25734 | Purpose |
| 25735 | ======= |
| 25736 | |
| 25737 | ZTREXC reorders the Schur factorization of a complex matrix |
| 25738 | A = Q*T*Q**H, so that the diagonal element of T with row index IFST |
| 25739 | is moved to row ILST. |
| 25740 | |
| 25741 | The Schur form T is reordered by a unitary similarity transformation |
| 25742 | Z**H*T*Z, and optionally the matrix Q of Schur vectors is updated by |
| 25743 | postmultplying it with Z. |
| 25744 | |
| 25745 | Arguments |
| 25746 | ========= |
| 25747 | |
| 25748 | COMPQ (input) CHARACTER*1 |
| 25749 | = 'V': update the matrix Q of Schur vectors; |
| 25750 | = 'N': do not update Q. |
| 25751 | |
| 25752 | N (input) INTEGER |
| 25753 | The order of the matrix T. N >= 0. |
| 25754 | |
| 25755 | T (input/output) COMPLEX*16 array, dimension (LDT,N) |
| 25756 | On entry, the upper triangular matrix T. |
| 25757 | On exit, the reordered upper triangular matrix. |
| 25758 | |
| 25759 | LDT (input) INTEGER |
| 25760 | The leading dimension of the array T. LDT >= max(1,N). |
| 25761 | |
| 25762 | Q (input/output) COMPLEX*16 array, dimension (LDQ,N) |
| 25763 | On entry, if COMPQ = 'V', the matrix Q of Schur vectors. |