Subroutine */
| 25588 | } /* ctrevc_ */ |
| 25589 | |
| 25590 | /* Subroutine */ int ctrexc_(char *compq, integer *n, complex *t, integer * |
| 25591 | ldt, complex *q, integer *ldq, integer *ifst, integer *ilst, integer * |
| 25592 | info) |
| 25593 | { |
| 25594 | /* System generated locals */ |
| 25595 | integer q_dim1, q_offset, t_dim1, t_offset, i__1, i__2, i__3; |
| 25596 | complex q__1; |
| 25597 | |
| 25598 | /* Local variables */ |
| 25599 | static integer k, m1, m2, m3; |
| 25600 | static real cs; |
| 25601 | static complex t11, t22, sn, temp; |
| 25602 | extern /* Subroutine */ int crot_(integer *, complex *, integer *, |
| 25603 | complex *, integer *, real *, complex *); |
| 25604 | extern logical lsame_(char *, char *); |
| 25605 | static logical wantq; |
| 25606 | extern /* Subroutine */ int clartg_(complex *, complex *, real *, complex |
| 25607 | *, complex *), xerbla_(char *, integer *); |
| 25608 | |
| 25609 | |
| 25610 | /* |
| 25611 | -- LAPACK routine (version 3.2) -- |
| 25612 | -- LAPACK is a software package provided by Univ. of Tennessee, -- |
| 25613 | -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- |
| 25614 | November 2006 |
| 25615 | |
| 25616 | |
| 25617 | Purpose |
| 25618 | ======= |
| 25619 | |
| 25620 | CTREXC reorders the Schur factorization of a complex matrix |
| 25621 | A = Q*T*Q**H, so that the diagonal element of T with row index IFST |
| 25622 | is moved to row ILST. |
| 25623 | |
| 25624 | The Schur form T is reordered by a unitary similarity transformation |
| 25625 | Z**H*T*Z, and optionally the matrix Q of Schur vectors is updated by |
| 25626 | postmultplying it with Z. |
| 25627 | |
| 25628 | Arguments |
| 25629 | ========= |
| 25630 | |
| 25631 | COMPQ (input) CHARACTER*1 |
| 25632 | = 'V': update the matrix Q of Schur vectors; |
| 25633 | = 'N': do not update Q. |
| 25634 | |
| 25635 | N (input) INTEGER |
| 25636 | The order of the matrix T. N >= 0. |
| 25637 | |
| 25638 | T (input/output) COMPLEX array, dimension (LDT,N) |
| 25639 | On entry, the upper triangular matrix T. |
| 25640 | On exit, the reordered upper triangular matrix. |
| 25641 | |
| 25642 | LDT (input) INTEGER |
| 25643 | The leading dimension of the array T. LDT >= max(1,N). |
| 25644 | |
| 25645 | Q (input/output) COMPLEX array, dimension (LDQ,N) |
| 25646 | On entry, if COMPQ = 'V', the matrix Q of Schur vectors. |
| 25647 | On exit, if COMPQ = 'V', Q has been postmultiplied by the |