/** ======================================================================* NIST Guide to Available Math Software.* Fullsource for module SSYEVX.C from package CLAPACK.* Retrieved from NETLIB on Fri Mar 10 14:23:44 2000.* ======================================================================*/#include <f2c.h>/* Subroutine */ int sormqr_(char *side, char *trans, integer *m, integer *n, 	integer *k, real *a, integer *lda, real *tau, real *c, integer *ldc, 	real *work, integer *lwork, integer *info){/*  -- LAPACK 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       =======       SORMQR overwrites the general real M-by-N matrix C with                       SIDE = 'L'     SIDE = 'R'       TRANS = 'N':      Q * C          C * Q       TRANS = 'T':      Q**T * C       C * Q**T       where Q is a real orthogonal matrix defined as the product of k       elementary reflectors             Q = H(1) H(2) . . . H(k)       as returned by SGEQRF. Q is of order M if SIDE = 'L' and of order N       if SIDE = 'R'.       Arguments       =========       SIDE    (input) CHARACTER*1               = 'L': apply Q or Q**T from the Left;               = 'R': apply Q or Q**T from the Right.       TRANS   (input) CHARACTER*1               = 'N':  No transpose, apply Q;               = 'T':  Transpose, apply Q**T.       M       (input) INTEGER               The number of rows of the matrix C. M >= 0.       N       (input) INTEGER               The number of columns of the matrix C. N >= 0.       K       (input) INTEGER               The number of elementary reflectors whose product defines               the matrix Q.               If SIDE = 'L', M >= K >= 0;               if SIDE = 'R', N >= K >= 0.       A       (input) REAL array, dimension (LDA,K)               The i-th column must contain the vector which defines the               elementary reflector H(i), for i = 1,2,...,k, as returned by               SGEQRF in the first k columns of its array argument A.               A is modified by the routine but restored on exit.       LDA     (input) INTEGER               The leading dimension of the array A.               If SIDE = 'L', LDA >= max(1,M);               if SIDE = 'R', LDA >= max(1,N).       TAU     (input) REAL array, dimension (K)               TAU(i) must contain the scalar factor of the elementary               reflector H(i), as returned by SGEQRF.       C       (input/output) REAL array, dimension (LDC,N)               On entry, the M-by-N matrix C.               On exit, C is overwritten by Q*C or Q**T*C or C*Q**T or C*Q.       LDC     (input) INTEGER               The leading dimension of the array C. LDC >= max(1,M).       WORK    (workspace/output) REAL array, dimension (LWORK)               On exit, if INFO = 0, WORK(1) returns the optimal LWORK.       LWORK   (input) INTEGER               The dimension of the array WORK.               If SIDE = 'L', LWORK >= max(1,N);               if SIDE = 'R', LWORK >= max(1,M).               For optimum performance LWORK >= N*NB if SIDE = 'L', and               LWORK >= M*NB if SIDE = 'R', where NB is the optimal               blocksize.       INFO    (output) INTEGER               = 0:  successful exit               < 0:  if INFO = -i, the i-th argument had an illegal value       =====================================================================          Test the input arguments          Parameter adjustments          Function Body */    /* Table of constant values */    static integer c__1 = 1;    static integer c_n1 = -1;    static integer c__2 = 2;    static integer c__65 = 65;        /* System generated locals */    address a__1[2];    integer a_dim1, a_offset, c_dim1, c_offset, i__1, i__2, i__3[2], i__4, 	    i__5;    char ch__1[2];    /* Builtin functions          Subroutine */ int s_cat(char *, char **, integer *, integer *, ftnlen);    /* Local variables */    static logical left;    static integer i;    static real t[4160]	/* was [65][64] */;    extern logical lsame_(char *, char *);    static integer nbmin, iinfo, i1, i2, i3, ib, ic, jc, nb;    extern /* Subroutine */ int sorm2r_(char *, char *, integer *, integer *, 	    integer *, real *, integer *, real *, real *, integer *, real *, 	    integer *);    static integer mi, ni, nq, nw;    extern /* Subroutine */ int slarfb_(char *, char *, char *, char *, 	    integer *, integer *, integer *, real *, integer *, real *, 	    integer *, real *, integer *, real *, integer *), xerbla_(char *, integer *);    extern integer ilaenv_(integer *, char *, char *, integer *, integer *, 	    integer *, integer *, ftnlen, ftnlen);    extern /* Subroutine */ int slarft_(char *, char *, integer *, integer *, 	    real *, integer *, real *, real *, integer *);    static logical notran;    static integer ldwork, iws;#define TAU(I) tau[(I)-1]#define WORK(I) work[(I)-1]#define A(I,J) a[(I)-1 + ((J)-1)* ( *lda)]#define C(I,J) c[(I)-1 + ((J)-1)* ( *ldc)]    *info = 0;    left = lsame_(side, "L");    notran = lsame_(trans, "N");/*     NQ is the order of Q and NW is the minimum dimension of WORK */    if (left) {	nq = *m;	nw = *n;    } else {	nq = *n;	nw = *m;    }    if (! left && ! lsame_(side, "R")) {	*info = -1;    } else if (! notran && ! lsame_(trans, "T")) {	*info = -2;    } else if (*m < 0) {	*info = -3;    } else if (*n < 0) {	*info = -4;    } else if (*k < 0 || *k > nq) {	*info = -5;    } else if (*lda < max(1,nq)) {	*info = -7;    } else if (*ldc < max(1,*m)) {	*info = -10;    } else if (*lwork < max(1,nw)) {	*info = -12;    }    if (*info != 0) {	i__1 = -(*info);	xerbla_("SORMQR", &i__1);	return 0;    }/*     Quick return if possible */    if (*m == 0 || *n == 0 || *k == 0) {	WORK(1) = 1.f;	return 0;    }/*     Determine the block size.  NB may be at most NBMAX, where NBMAX          is used to define the local array T.      Computing MIN      Writing concatenation */    i__3[0] = 1, a__1[0] = side;    i__3[1] = 1, a__1[1] = trans;    s_cat(ch__1, a__1, i__3, &c__2, 2L);    i__1 = 64, i__2 = ilaenv_(&c__1, "SORMQR", ch__1, m, n, k, &c_n1, 6L, 2L);    nb = min(i__1,i__2);    nbmin = 2;    ldwork = nw;    if (nb > 1 && nb < *k) {	iws = nw * nb;	if (*lwork < iws) {	    nb = *lwork / ldwork;/* Computing MAX      Writing concatenation */	    i__3[0] = 1, a__1[0] = side;	    i__3[1] = 1, a__1[1] = trans;	    s_cat(ch__1, a__1, i__3, &c__2, 2L);	    i__1 = 2, i__2 = ilaenv_(&c__2, "SORMQR", ch__1, m, n, k, &c_n1, 		    6L, 2L);	    nbmin = max(i__1,i__2);	}    } else {	iws = nw;    }    if (nb < nbmin || nb >= *k) {/*        Use unblocked code */	sorm2r_(side, trans, m, n, k, &A(1,1), lda, &TAU(1), &C(1,1)		, ldc, &WORK(1), &iinfo);    } else {/*        Use blocked code */	if (left && ! notran || ! left && notran) {	    i1 = 1;	    i2 = *k;	    i3 = nb;	} else {	    i1 = (*k - 1) / nb * nb + 1;	    i2 = 1;	    i3 = -nb;	}	if (left) {	    ni = *n;	    jc = 1;	} else {	    mi = *m;	    ic = 1;	}	i__1 = i2;	i__2 = i3;	for (i = i1; i3 < 0 ? i >= i2 : i <= i2; i += i3) {/* Computing MIN */	    i__4 = nb, i__5 = *k - i + 1;	    ib = min(i__4,i__5);/*           Form the triangular factor of the block reflector                H = H(i) H(i+1) . . . H(i+ib-1) */	    i__4 = nq - i + 1;	    slarft_("Forward", "Columnwise", &i__4, &ib, &A(i,i), 		    lda, &TAU(i), t, &c__65);	    if (left) {/*              H or H' is applied to C(i:m,1:n) */		mi = *m - i + 1;		ic = i;	    } else {/*              H or H' is applied to C(1:m,i:n) */		ni = *n - i + 1;		jc = i;	    }/*           Apply H or H' */	    slarfb_(side, trans, "Forward", "Columnwise", &mi, &ni, &ib, &A(i,i), lda, t, &c__65, &C(ic,jc), ldc, 		    &WORK(1), &ldwork);/* L10: */	}    }    WORK(1) = (real) iws;    return 0;/*     End of SORMQR */} /* sormqr_ */