Subroutine */
| 3203 | } /* dgeev_ */ |
| 3204 | |
| 3205 | /* Subroutine */ int dgehd2_(integer *n, integer *ilo, integer *ihi, |
| 3206 | doublereal *a, integer *lda, doublereal *tau, doublereal *work, |
| 3207 | integer *info) |
| 3208 | { |
| 3209 | /* System generated locals */ |
| 3210 | integer a_dim1, a_offset, i__1, i__2, i__3; |
| 3211 | |
| 3212 | /* Local variables */ |
| 3213 | static integer i__; |
| 3214 | static doublereal aii; |
| 3215 | extern /* Subroutine */ int dlarf_(char *, integer *, integer *, |
| 3216 | doublereal *, integer *, doublereal *, doublereal *, integer *, |
| 3217 | doublereal *), dlarfg_(integer *, doublereal *, |
| 3218 | doublereal *, integer *, doublereal *), xerbla_(char *, integer *); |
| 3219 | |
| 3220 | |
| 3221 | /* |
| 3222 | -- LAPACK routine (version 3.2) -- |
| 3223 | -- LAPACK is a software package provided by Univ. of Tennessee, -- |
| 3224 | -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- |
| 3225 | November 2006 |
| 3226 | |
| 3227 | |
| 3228 | Purpose |
| 3229 | ======= |
| 3230 | |
| 3231 | DGEHD2 reduces a real general matrix A to upper Hessenberg form H by |
| 3232 | an orthogonal similarity transformation: Q' * A * Q = H . |
| 3233 | |
| 3234 | Arguments |
| 3235 | ========= |
| 3236 | |
| 3237 | N (input) INTEGER |
| 3238 | The order of the matrix A. N >= 0. |
| 3239 | |
| 3240 | ILO (input) INTEGER |
| 3241 | IHI (input) INTEGER |
| 3242 | It is assumed that A is already upper triangular in rows |
| 3243 | and columns 1:ILO-1 and IHI+1:N. ILO and IHI are normally |
| 3244 | set by a previous call to DGEBAL; otherwise they should be |
| 3245 | set to 1 and N respectively. See Further Details. |
| 3246 | 1 <= ILO <= IHI <= max(1,N). |
| 3247 | |
| 3248 | A (input/output) DOUBLE PRECISION array, dimension (LDA,N) |
| 3249 | On entry, the n by n general matrix to be reduced. |
| 3250 | On exit, the upper triangle and the first subdiagonal of A |
| 3251 | are overwritten with the upper Hessenberg matrix H, and the |
| 3252 | elements below the first subdiagonal, with the array TAU, |
| 3253 | represent the orthogonal matrix Q as a product of elementary |
| 3254 | reflectors. See Further Details. |
| 3255 | |
| 3256 | LDA (input) INTEGER |
| 3257 | The leading dimension of the array A. LDA >= max(1,N). |
| 3258 | |
| 3259 | TAU (output) DOUBLE PRECISION array, dimension (N-1) |
| 3260 | The scalar factors of the elementary reflectors (see Further |
| 3261 | Details). |
| 3262 |