Subroutine */
| 1823 | } /* zgeev_ */ |
| 1824 | |
| 1825 | /* Subroutine */ int zgehd2_(integer *n, integer *ilo, integer *ihi, |
| 1826 | doublecomplex *a, integer *lda, doublecomplex *tau, doublecomplex * |
| 1827 | work, integer *info) |
| 1828 | { |
| 1829 | /* System generated locals */ |
| 1830 | integer a_dim1, a_offset, i__1, i__2, i__3; |
| 1831 | doublecomplex z__1; |
| 1832 | |
| 1833 | /* Local variables */ |
| 1834 | static integer i__; |
| 1835 | static doublecomplex alpha; |
| 1836 | extern /* Subroutine */ int zlarf_(char *, integer *, integer *, |
| 1837 | doublecomplex *, integer *, doublecomplex *, doublecomplex *, |
| 1838 | integer *, doublecomplex *), xerbla_(char *, integer *), zlarfg_(integer *, doublecomplex *, doublecomplex *, |
| 1839 | integer *, doublecomplex *); |
| 1840 | |
| 1841 | |
| 1842 | /* |
| 1843 | -- LAPACK routine (version 3.2) -- |
| 1844 | -- LAPACK is a software package provided by Univ. of Tennessee, -- |
| 1845 | -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- |
| 1846 | November 2006 |
| 1847 | |
| 1848 | |
| 1849 | Purpose |
| 1850 | ======= |
| 1851 | |
| 1852 | ZGEHD2 reduces a complex general matrix A to upper Hessenberg form H |
| 1853 | by a unitary similarity transformation: Q' * A * Q = H . |
| 1854 | |
| 1855 | Arguments |
| 1856 | ========= |
| 1857 | |
| 1858 | N (input) INTEGER |
| 1859 | The order of the matrix A. N >= 0. |
| 1860 | |
| 1861 | ILO (input) INTEGER |
| 1862 | IHI (input) INTEGER |
| 1863 | It is assumed that A is already upper triangular in rows |
| 1864 | and columns 1:ILO-1 and IHI+1:N. ILO and IHI are normally |
| 1865 | set by a previous call to ZGEBAL; otherwise they should be |
| 1866 | set to 1 and N respectively. See Further Details. |
| 1867 | 1 <= ILO <= IHI <= max(1,N). |
| 1868 | |
| 1869 | A (input/output) COMPLEX*16 array, dimension (LDA,N) |
| 1870 | On entry, the n by n general matrix to be reduced. |
| 1871 | On exit, the upper triangle and the first subdiagonal of A |
| 1872 | are overwritten with the upper Hessenberg matrix H, and the |
| 1873 | elements below the first subdiagonal, with the array TAU, |
| 1874 | represent the unitary matrix Q as a product of elementary |
| 1875 | reflectors. See Further Details. |
| 1876 | |
| 1877 | LDA (input) INTEGER |
| 1878 | The leading dimension of the array A. LDA >= max(1,N). |
| 1879 | |
| 1880 | TAU (output) COMPLEX*16 array, dimension (N-1) |
| 1881 | The scalar factors of the elementary reflectors (see Further |
| 1882 | Details). |