/* Copyright (c) 1992-2008 The University of Tennessee.  All rights reserved.
 * See file COPYING in this directory for details. */

#ifdef __cplusplus
extern "C" {
#endif

#include "f2c.h"
#include "hypre_lapack.h"

/* Subroutine */ integer dlarfb_(const char *side,const char *trans,const char *direct,const char *
	storev, integer *m, integer *n, integer *k, doublereal *v, integer *
	ldv, doublereal *t, integer *ldt, doublereal *c__, integer *ldc, 
	doublereal *work, integer *ldwork)
{
/*  -- LAPACK auxiliary routine (version 3.0) --   
       Univ. of Tennessee, Univ. of California Berkeley, NAG Ltd.,   
       Courant Institute, Argonne National Lab, and Rice University   
       February 29, 1992   


    Purpose   
    =======   

    DLARFB applies a real block reflector H or its transpose H' to a   
    real m by n matrix C, from either the left or the right.   

    Arguments   
    =========   

    SIDE    (input) CHARACTER*1   
            = 'L': apply H or H' from the Left   
            = 'R': apply H or H' from the Right   

    TRANS   (input) CHARACTER*1   
            = 'N': apply H (No transpose)   
            = 'T': apply H' (Transpose)   

    DIRECT  (input) CHARACTER*1   
            Indicates how H is formed from a product of elementary   
            reflectors   
            = 'F': H = H(1) H(2) . . . H(k) (Forward)   
            = 'B': H = H(k) . . . H(2) H(1) (Backward)   

    STOREV  (input) CHARACTER*1   
            Indicates how the vectors which define the elementary   
            reflectors are stored:   
            = 'C': Columnwise   
            = 'R': Rowwise   

    M       (input) INTEGER   
            The number of rows of the matrix C.   

    N       (input) INTEGER   
            The number of columns of the matrix C.   

    K       (input) INTEGER   
            The order of the matrix T (= the number of elementary   
            reflectors whose product defines the block reflector).   

    V       (input) DOUBLE PRECISION array, dimension   
                                  (LDV,K) if STOREV = 'C'   
                                  (LDV,M) if STOREV = 'R' and SIDE = 'L'   
                                  (LDV,N) if STOREV = 'R' and SIDE = 'R'   
            The matrix V. See further details.   

    LDV     (input) INTEGER   
            The leading dimension of the array V.   
            If STOREV = 'C' and SIDE = 'L', LDV >= max(1,M);   
            if STOREV = 'C' and SIDE = 'R', LDV >= max(1,N);   
            if STOREV = 'R', LDV >= K.   

    T       (input) DOUBLE PRECISION array, dimension (LDT,K)   
            The triangular k by k matrix T in the representation of the   
            block reflector.   

    LDT     (input) INTEGER   
            The leading dimension of the array T. LDT >= K.   

    C       (input/output) DOUBLE PRECISION array, dimension (LDC,N)   
            On entry, the m by n matrix C.   
            On exit, C is overwritten by H*C or H'*C or C*H or C*H'.   

    LDC     (input) INTEGER   
            The leading dimension of the array C. LDA >= max(1,M).   

    WORK    (workspace) DOUBLE PRECISION array, dimension (LDWORK,K)   

    LDWORK  (input) INTEGER   
            The leading dimension of the array WORK.   
            If SIDE = 'L', LDWORK >= max(1,N);   
            if SIDE = 'R', LDWORK >= max(1,M).   

    =====================================================================   


       Quick return if possible   

       Parameter adjustments */
    /* Table of constant values */
     integer c__1 = 1;
     doublereal c_b14 = 1.;
     doublereal c_b25 = -1.;
    
    /* System generated locals */
    integer c_dim1, c_offset, t_dim1, t_offset, v_dim1, v_offset, work_dim1, 
	    work_offset, i__1, i__2;
    /* Local variables */
     integer i__, j;
    extern /* Subroutine */ integer dgemm_(const char *,const char *, integer *, integer *, 
	    integer *, doublereal *, doublereal *, integer *, doublereal *, 
	    integer *, doublereal *, doublereal *, integer *);
    extern logical lsame_(const char *,const char *);
    extern /* Subroutine */ integer dcopy_(integer *, doublereal *, integer *, 
	    doublereal *, integer *), dtrmm_(const char *,const char *,const char *,const char *, 
	    integer *, integer *, doublereal *, doublereal *, integer *, 
	    doublereal *, integer *);
     char transt[1];
#define work_ref(a_1,a_2) work[(a_2)*work_dim1 + a_1]
#define c___ref(a_1,a_2) c__[(a_2)*c_dim1 + a_1]
#define v_ref(a_1,a_2) v[(a_2)*v_dim1 + a_1]


    v_dim1 = *ldv;
    v_offset = 1 + v_dim1 * 1;
    v -= v_offset;
    t_dim1 = *ldt;
    t_offset = 1 + t_dim1 * 1;
    t -= t_offset;
    c_dim1 = *ldc;
    c_offset = 1 + c_dim1 * 1;
    c__ -= c_offset;
    work_dim1 = *ldwork;
    work_offset = 1 + work_dim1 * 1;
    work -= work_offset;

    /* Function Body */
    if (*m <= 0 || *n <= 0) {
	return 0;
    }

    if (lsame_(trans, "N")) {
	*(unsigned char *)transt = 'T';
    } else {
	*(unsigned char *)transt = 'N';
    }

    if (lsame_(storev, "C")) {

	if (lsame_(direct, "F")) {

/*           Let  V =  ( V1 )    (first K rows)   
                       ( V2 )   
             where  V1  is unit lower triangular. */

	    if (lsame_(side, "L")) {

/*              Form  H * C  or  H' * C  where  C = ( C1 )   
                                                    ( C2 )   

                W := C' * V  =  (C1'*V1 + C2'*V2)  (stored in WORK)   

                W := C1' */

		i__1 = *k;
		for (j = 1; j <= i__1; ++j) {
		    dcopy_(n, &c___ref(j, 1), ldc, &work_ref(1, j), &c__1);
/* L10: */
		}

/*              W := W * V1 */

		dtrmm_("Right", "Lower", "No transpose", "Unit", n, k, &c_b14,
			 &v[v_offset], ldv, &work[work_offset], ldwork);
		if (*m > *k) {

/*                 W := W + C2'*V2 */

		    i__1 = *m - *k;
		    dgemm_("Transpose", "No transpose", n, k, &i__1, &c_b14, &
			    c___ref(*k + 1, 1), ldc, &v_ref(*k + 1, 1), ldv, &
			    c_b14, &work[work_offset], ldwork);
		}

/*              W := W * T'  or  W * T */

		dtrmm_("Right", "Upper", transt, "Non-unit", n, k, &c_b14, &t[
			t_offset], ldt, &work[work_offset], ldwork);

/*              C := C - V * W' */

		if (*m > *k) {

/*                 C2 := C2 - V2 * W' */

		    i__1 = *m - *k;
		    dgemm_("No transpose", "Transpose", &i__1, n, k, &c_b25, &
			    v_ref(*k + 1, 1), ldv, &work[work_offset], ldwork,
			     &c_b14, &c___ref(*k + 1, 1), ldc);
		}

/*              W := W * V1' */

		dtrmm_("Right", "Lower", "Transpose", "Unit", n, k, &c_b14, &
			v[v_offset], ldv, &work[work_offset], ldwork);

/*              C1 := C1 - W' */

		i__1 = *k;
		for (j = 1; j <= i__1; ++j) {
		    i__2 = *n;
		    for (i__ = 1; i__ <= i__2; ++i__) {
			c___ref(j, i__) = c___ref(j, i__) - work_ref(i__, j);
/* L20: */
		    }
/* L30: */
		}

	    } else if (lsame_(side, "R")) {

/*              Form  C * H  or  C * H'  where  C = ( C1  C2 )   

                W := C * V  =  (C1*V1 + C2*V2)  (stored in WORK)   

                W := C1 */

		i__1 = *k;
		for (j = 1; j <= i__1; ++j) {
		    dcopy_(m, &c___ref(1, j), &c__1, &work_ref(1, j), &c__1);
/* L40: */
		}

/*              W := W * V1 */

		dtrmm_("Right", "Lower", "No transpose", "Unit", m, k, &c_b14,
			 &v[v_offset], ldv, &work[work_offset], ldwork);
		if (*n > *k) {

/*                 W := W + C2 * V2 */

		    i__1 = *n - *k;
		    dgemm_("No transpose", "No transpose", m, k, &i__1, &
			    c_b14, &c___ref(1, *k + 1), ldc, &v_ref(*k + 1, 1)
			    , ldv, &c_b14, &work[work_offset], ldwork);
		}

/*              W := W * T  or  W * T' */

		dtrmm_("Right", "Upper", trans, "Non-unit", m, k, &c_b14, &t[
			t_offset], ldt, &work[work_offset], ldwork);

/*              C := C - W * V' */

		if (*n > *k) {

/*                 C2 := C2 - W * V2' */

		    i__1 = *n - *k;
		    dgemm_("No transpose", "Transpose", m, &i__1, k, &c_b25, &
			    work[work_offset], ldwork, &v_ref(*k + 1, 1), ldv,
			     &c_b14, &c___ref(1, *k + 1), ldc);
		}

/*              W := W * V1' */

		dtrmm_("Right", "Lower", "Transpose", "Unit", m, k, &c_b14, &
			v[v_offset], ldv, &work[work_offset], ldwork);

/*              C1 := C1 - W */

		i__1 = *k;
		for (j = 1; j <= i__1; ++j) {
		    i__2 = *m;
		    for (i__ = 1; i__ <= i__2; ++i__) {
			c___ref(i__, j) = c___ref(i__, j) - work_ref(i__, j);
/* L50: */
		    }
/* L60: */
		}
	    }

	} else {

/*           Let  V =  ( V1 )   
                       ( V2 )    (last K rows)   
             where  V2  is unit upper triangular. */

	    if (lsame_(side, "L")) {

/*              Form  H * C  or  H' * C  where  C = ( C1 )   
                                                    ( C2 )   

                W := C' * V  =  (C1'*V1 + C2'*V2)  (stored in WORK)   

                W := C2' */

		i__1 = *k;
		for (j = 1; j <= i__1; ++j) {
		    dcopy_(n, &c___ref(*m - *k + j, 1), ldc, &work_ref(1, j), 
			    &c__1);
/* L70: */
		}

/*              W := W * V2 */

		dtrmm_("Right", "Upper", "No transpose", "Unit", n, k, &c_b14,
			 &v_ref(*m - *k + 1, 1), ldv, &work[work_offset], 
			ldwork);
		if (*m > *k) {

/*                 W := W + C1'*V1 */

		    i__1 = *m - *k;
		    dgemm_("Transpose", "No transpose", n, k, &i__1, &c_b14, &
			    c__[c_offset], ldc, &v[v_offset], ldv, &c_b14, &
			    work[work_offset], ldwork);
		}

/*              W := W * T'  or  W * T */

		dtrmm_("Right", "Lower", transt, "Non-unit", n, k, &c_b14, &t[
			t_offset], ldt, &work[work_offset], ldwork);

/*              C := C - V * W' */

		if (*m > *k) {

/*                 C1 := C1 - V1 * W' */

		    i__1 = *m - *k;
		    dgemm_("No transpose", "Transpose", &i__1, n, k, &c_b25, &
			    v[v_offset], ldv, &work[work_offset], ldwork, &
			    c_b14, &c__[c_offset], ldc)
			    ;
		}

/*              W := W * V2' */

		dtrmm_("Right", "Upper", "Transpose", "Unit", n, k, &c_b14, &
			v_ref(*m - *k + 1, 1), ldv, &work[work_offset], 
			ldwork);

/*              C2 := C2 - W' */

		i__1 = *k;
		for (j = 1; j <= i__1; ++j) {
		    i__2 = *n;
		    for (i__ = 1; i__ <= i__2; ++i__) {
			c___ref(*m - *k + j, i__) = c___ref(*m - *k + j, i__) 
				- work_ref(i__, j);
/* L80: */
		    }
/* L90: */
		}

	    } else if (lsame_(side, "R")) {

/*              Form  C * H  or  C * H'  where  C = ( C1  C2 )   

                W := C * V  =  (C1*V1 + C2*V2)  (stored in WORK)   

                W := C2 */

		i__1 = *k;
		for (j = 1; j <= i__1; ++j) {
		    dcopy_(m, &c___ref(1, *n - *k + j), &c__1, &work_ref(1, j)
			    , &c__1);
/* L100: */
		}

/*              W := W * V2 */

		dtrmm_("Right", "Upper", "No transpose", "Unit", m, k, &c_b14,
			 &v_ref(*n - *k + 1, 1), ldv, &work[work_offset], 
			ldwork);
		if (*n > *k) {

/*                 W := W + C1 * V1 */

		    i__1 = *n - *k;
		    dgemm_("No transpose", "No transpose", m, k, &i__1, &
			    c_b14, &c__[c_offset], ldc, &v[v_offset], ldv, &
			    c_b14, &work[work_offset], ldwork);
		}

/*              W := W * T  or  W * T' */

		dtrmm_("Right", "Lower", trans, "Non-unit", m, k, &c_b14, &t[
			t_offset], ldt, &work[work_offset], ldwork);

/*              C := C - W * V' */

		if (*n > *k) {

/*                 C1 := C1 - W * V1' */

		    i__1 = *n - *k;
		    dgemm_("No transpose", "Transpose", m, &i__1, k, &c_b25, &
			    work[work_offset], ldwork, &v[v_offset], ldv, &
			    c_b14, &c__[c_offset], ldc)
			    ;
		}

/*              W := W * V2' */

		dtrmm_("Right", "Upper", "Transpose", "Unit", m, k, &c_b14, &
			v_ref(*n - *k + 1, 1), ldv, &work[work_offset], 
			ldwork);

/*              C2 := C2 - W */

		i__1 = *k;
		for (j = 1; j <= i__1; ++j) {
		    i__2 = *m;
		    for (i__ = 1; i__ <= i__2; ++i__) {
			c___ref(i__, *n - *k + j) = c___ref(i__, *n - *k + j) 
				- work_ref(i__, j);
/* L110: */
		    }
/* L120: */
		}
	    }
	}

    } else if (lsame_(storev, "R")) {

	if (lsame_(direct, "F")) {

/*           Let  V =  ( V1  V2 )    (V1: first K columns)   
             where  V1  is unit upper triangular. */

	    if (lsame_(side, "L")) {

/*              Form  H * C  or  H' * C  where  C = ( C1 )   
                                                    ( C2 )   

                W := C' * V'  =  (C1'*V1' + C2'*V2') (stored in WORK)   

                W := C1' */

		i__1 = *k;
		for (j = 1; j <= i__1; ++j) {
		    dcopy_(n, &c___ref(j, 1), ldc, &work_ref(1, j), &c__1);
/* L130: */
		}

/*              W := W * V1' */

		dtrmm_("Right", "Upper", "Transpose", "Unit", n, k, &c_b14, &
			v[v_offset], ldv, &work[work_offset], ldwork);
		if (*m > *k) {

/*                 W := W + C2'*V2' */

		    i__1 = *m - *k;
		    dgemm_("Transpose", "Transpose", n, k, &i__1, &c_b14, &
			    c___ref(*k + 1, 1), ldc, &v_ref(1, *k + 1), ldv, &
			    c_b14, &work[work_offset], ldwork);
		}

/*              W := W * T'  or  W * T */

		dtrmm_("Right", "Upper", transt, "Non-unit", n, k, &c_b14, &t[
			t_offset], ldt, &work[work_offset], ldwork);

/*              C := C - V' * W' */

		if (*m > *k) {

/*                 C2 := C2 - V2' * W' */

		    i__1 = *m - *k;
		    dgemm_("Transpose", "Transpose", &i__1, n, k, &c_b25, &
			    v_ref(1, *k + 1), ldv, &work[work_offset], ldwork,
			     &c_b14, &c___ref(*k + 1, 1), ldc);
		}

/*              W := W * V1 */

		dtrmm_("Right", "Upper", "No transpose", "Unit", n, k, &c_b14,
			 &v[v_offset], ldv, &work[work_offset], ldwork);

/*              C1 := C1 - W' */

		i__1 = *k;
		for (j = 1; j <= i__1; ++j) {
		    i__2 = *n;
		    for (i__ = 1; i__ <= i__2; ++i__) {
			c___ref(j, i__) = c___ref(j, i__) - work_ref(i__, j);
/* L140: */
		    }
/* L150: */
		}

	    } else if (lsame_(side, "R")) {

/*              Form  C * H  or  C * H'  where  C = ( C1  C2 )   

                W := C * V'  =  (C1*V1' + C2*V2')  (stored in WORK)   

                W := C1 */

		i__1 = *k;
		for (j = 1; j <= i__1; ++j) {
		    dcopy_(m, &c___ref(1, j), &c__1, &work_ref(1, j), &c__1);
/* L160: */
		}

/*              W := W * V1' */

		dtrmm_("Right", "Upper", "Transpose", "Unit", m, k, &c_b14, &
			v[v_offset], ldv, &work[work_offset], ldwork);
		if (*n > *k) {

/*                 W := W + C2 * V2' */

		    i__1 = *n - *k;
		    dgemm_("No transpose", "Transpose", m, k, &i__1, &c_b14, &
			    c___ref(1, *k + 1), ldc, &v_ref(1, *k + 1), ldv, &
			    c_b14, &work[work_offset], ldwork);
		}

/*              W := W * T  or  W * T' */

		dtrmm_("Right", "Upper", trans, "Non-unit", m, k, &c_b14, &t[
			t_offset], ldt, &work[work_offset], ldwork);

/*              C := C - W * V */

		if (*n > *k) {

/*                 C2 := C2 - W * V2 */

		    i__1 = *n - *k;
		    dgemm_("No transpose", "No transpose", m, &i__1, k, &
			    c_b25, &work[work_offset], ldwork, &v_ref(1, *k + 
			    1), ldv, &c_b14, &c___ref(1, *k + 1), ldc);
		}

/*              W := W * V1 */

		dtrmm_("Right", "Upper", "No transpose", "Unit", m, k, &c_b14,
			 &v[v_offset], ldv, &work[work_offset], ldwork);

/*              C1 := C1 - W */

		i__1 = *k;
		for (j = 1; j <= i__1; ++j) {
		    i__2 = *m;
		    for (i__ = 1; i__ <= i__2; ++i__) {
			c___ref(i__, j) = c___ref(i__, j) - work_ref(i__, j);
/* L170: */
		    }
/* L180: */
		}

	    }

	} else {

/*           Let  V =  ( V1  V2 )    (V2: last K columns)   
             where  V2  is unit lower triangular. */

	    if (lsame_(side, "L")) {

/*              Form  H * C  or  H' * C  where  C = ( C1 )   
                                                    ( C2 )   

                W := C' * V'  =  (C1'*V1' + C2'*V2') (stored in WORK)   

                W := C2' */

		i__1 = *k;
		for (j = 1; j <= i__1; ++j) {
		    dcopy_(n, &c___ref(*m - *k + j, 1), ldc, &work_ref(1, j), 
			    &c__1);
/* L190: */
		}

/*              W := W * V2' */

		dtrmm_("Right", "Lower", "Transpose", "Unit", n, k, &c_b14, &
			v_ref(1, *m - *k + 1), ldv, &work[work_offset], 
			ldwork);
		if (*m > *k) {

/*                 W := W + C1'*V1' */

		    i__1 = *m - *k;
		    dgemm_("Transpose", "Transpose", n, k, &i__1, &c_b14, &
			    c__[c_offset], ldc, &v[v_offset], ldv, &c_b14, &
			    work[work_offset], ldwork);
		}

/*              W := W * T'  or  W * T */

		dtrmm_("Right", "Lower", transt, "Non-unit", n, k, &c_b14, &t[
			t_offset], ldt, &work[work_offset], ldwork);

/*              C := C - V' * W' */

		if (*m > *k) {

/*                 C1 := C1 - V1' * W' */

		    i__1 = *m - *k;
		    dgemm_("Transpose", "Transpose", &i__1, n, k, &c_b25, &v[
			    v_offset], ldv, &work[work_offset], ldwork, &
			    c_b14, &c__[c_offset], ldc);
		}

/*              W := W * V2 */

		dtrmm_("Right", "Lower", "No transpose", "Unit", n, k, &c_b14,
			 &v_ref(1, *m - *k + 1), ldv, &work[work_offset], 
			ldwork);

/*              C2 := C2 - W' */

		i__1 = *k;
		for (j = 1; j <= i__1; ++j) {
		    i__2 = *n;
		    for (i__ = 1; i__ <= i__2; ++i__) {
			c___ref(*m - *k + j, i__) = c___ref(*m - *k + j, i__) 
				- work_ref(i__, j);
/* L200: */
		    }
/* L210: */
		}

	    } else if (lsame_(side, "R")) {

/*              Form  C * H  or  C * H'  where  C = ( C1  C2 )   

                W := C * V'  =  (C1*V1' + C2*V2')  (stored in WORK)   

                W := C2 */

		i__1 = *k;
		for (j = 1; j <= i__1; ++j) {
		    dcopy_(m, &c___ref(1, *n - *k + j), &c__1, &work_ref(1, j)
			    , &c__1);
/* L220: */
		}

/*              W := W * V2' */

		dtrmm_("Right", "Lower", "Transpose", "Unit", m, k, &c_b14, &
			v_ref(1, *n - *k + 1), ldv, &work[work_offset], 
			ldwork);
		if (*n > *k) {

/*                 W := W + C1 * V1' */

		    i__1 = *n - *k;
		    dgemm_("No transpose", "Transpose", m, k, &i__1, &c_b14, &
			    c__[c_offset], ldc, &v[v_offset], ldv, &c_b14, &
			    work[work_offset], ldwork);
		}

/*              W := W * T  or  W * T' */

		dtrmm_("Right", "Lower", trans, "Non-unit", m, k, &c_b14, &t[
			t_offset], ldt, &work[work_offset], ldwork);

/*              C := C - W * V */

		if (*n > *k) {

/*                 C1 := C1 - W * V1 */

		    i__1 = *n - *k;
		    dgemm_("No transpose", "No transpose", m, &i__1, k, &
			    c_b25, &work[work_offset], ldwork, &v[v_offset], 
			    ldv, &c_b14, &c__[c_offset], ldc);
		}

/*              W := W * V2 */

		dtrmm_("Right", "Lower", "No transpose", "Unit", m, k, &c_b14,
			 &v_ref(1, *n - *k + 1), ldv, &work[work_offset], 
			ldwork);

/*              C1 := C1 - W */

		i__1 = *k;
		for (j = 1; j <= i__1; ++j) {
		    i__2 = *m;
		    for (i__ = 1; i__ <= i__2; ++i__) {
			c___ref(i__, *n - *k + j) = c___ref(i__, *n - *k + j) 
				- work_ref(i__, j);
/* L230: */
		    }
/* L240: */
		}

	    }

	}
    }

    return 0;

/*     End of DLARFB */

} /* dlarfb_ */

#undef v_ref
#undef c___ref
#undef work_ref

#ifdef __cplusplus
}
#endif
