/* -- translated by f2c (version 19940927). You must link the resulting object file with the libraries: -lf2c -lm (in that order) */ #include "f2c.h" /* Table of constant values */ static complex c_b1 = {0.f,0.f}; static complex c_b2 = {1.f,0.f}; static integer c__3 = 3; static integer c__1 = 1; /* Subroutine */ int clarge_slu(integer *n, complex *a, integer *lda, integer * iseed, complex *work, integer *info) { /* System generated locals */ integer a_dim1, a_offset, i__1; doublereal d__1; complex q__1; /* Builtin functions */ double c_abs(complex *); void c_div(complex *, complex *, complex *); /* Local variables */ static integer i; extern /* Subroutine */ int cgerc_(integer *, integer *, complex *, complex *, integer *, complex *, integer *, complex *, integer *), cscal_(integer *, complex *, complex *, integer *), cgemv_(char * , integer *, integer *, complex *, complex *, integer *, complex * , integer *, complex *, complex *, integer *); extern real scnrm2_(integer *, complex *, integer *); static complex wa, wb; static real wn; extern /* Subroutine */ int clarnv_slu(integer *, integer *, integer *, complex *); extern int input_error(char *, int *); static complex tau; /* -- LAPACK auxiliary test routine (version 2.0) -- Univ. of Tennessee, Univ. of California Berkeley, NAG Ltd., Courant Institute, Argonne National Lab, and Rice University September 30, 1994 Purpose ======= CLARGE pre- and post-multiplies a complex general n by n matrix A with a random unitary matrix: A = U*D*U'. Arguments ========= N (input) INTEGER The order of the matrix A. N >= 0. A (input/output) COMPLEX array, dimension (LDA,N) On entry, the original n by n matrix A. On exit, A is overwritten by U*A*U' for some random unitary matrix U. LDA (input) INTEGER The leading dimension of the array A. LDA >= N. ISEED (input/output) INTEGER array, dimension (4) On entry, the seed of the random number generator; the array elements must be between 0 and 4095, and ISEED(4) must be odd. On exit, the seed is updated. WORK (workspace) COMPLEX array, dimension (2*N) INFO (output) INTEGER = 0: successful exit < 0: if INFO = -i, the i-th argument had an illegal value ===================================================================== Test the input arguments Parameter adjustments */ a_dim1 = *lda; a_offset = a_dim1 + 1; a -= a_offset; --iseed; --work; /* Function Body */ *info = 0; if (*n < 0) { *info = -1; } else if (*lda < max(1,*n)) { *info = -3; } if (*info < 0) { i__1 = -(*info); input_error("CLARGE", &i__1); return 0; } /* pre- and post-multiply A by random unitary matrix */ for (i = *n; i >= 1; --i) { /* generate random reflection */ i__1 = *n - i + 1; clarnv_slu(&c__3, &iseed[1], &i__1, &work[1]); i__1 = *n - i + 1; wn = scnrm2_(&i__1, &work[1], &c__1); d__1 = wn / c_abs(&work[1]); q__1.r = d__1 * work[1].r, q__1.i = d__1 * work[1].i; wa.r = q__1.r, wa.i = q__1.i; if (wn == 0.f) { tau.r = 0.f, tau.i = 0.f; } else { q__1.r = work[1].r + wa.r, q__1.i = work[1].i + wa.i; wb.r = q__1.r, wb.i = q__1.i; i__1 = *n - i; c_div(&q__1, &c_b2, &wb); cscal_(&i__1, &q__1, &work[2], &c__1); work[1].r = 1.f, work[1].i = 0.f; c_div(&q__1, &wb, &wa); d__1 = q__1.r; tau.r = d__1, tau.i = 0.f; } /* multiply A(i:n,1:n) by random reflection from the left */ i__1 = *n - i + 1; cgemv_("Conjugate transpose", &i__1, n, &c_b2, &a[i + a_dim1], lda, & work[1], &c__1, &c_b1, &work[*n + 1], &c__1); i__1 = *n - i + 1; q__1.r = -(doublereal)tau.r, q__1.i = -(doublereal)tau.i; cgerc_(&i__1, n, &q__1, &work[1], &c__1, &work[*n + 1], &c__1, &a[i + a_dim1], lda); /* multiply A(1:n,i:n) by random reflection from the right */ i__1 = *n - i + 1; cgemv_("No transpose", n, &i__1, &c_b2, &a[i * a_dim1 + 1], lda, & work[1], &c__1, &c_b1, &work[*n + 1], &c__1); i__1 = *n - i + 1; q__1.r = -(doublereal)tau.r, q__1.i = -(doublereal)tau.i; cgerc_(n, &i__1, &q__1, &work[*n + 1], &c__1, &work[1], &c__1, &a[i * a_dim1 + 1], lda); /* L10: */ } return 0; /* End of CLARGE */ } /* clarge_slu */