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/*! @file ssp_blas2.c
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 * \brief Sparse BLAS 2, using some dense BLAS 2 operations
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 *
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 * 
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 * -- SuperLU routine (version 3.0) --
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 * Univ. of California Berkeley, Xerox Palo Alto Research Center,
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 * and Lawrence Berkeley National Lab.
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 * October 15, 2003
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 * 
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 */
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/*
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 * File name:		ssp_blas2.c
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 * Purpose:		Sparse BLAS 2, using some dense BLAS 2 operations.
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 */
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#include "slu_sdefs.h"
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/* 
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 * Function prototypes 
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 */
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void susolve(int, int, float*, float*);
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void slsolve(int, int, float*, float*);
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void smatvec(int, int, int, float*, float*, float*);
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/*! \brief Solves one of the systems of equations A*x = b,   or   A'*x = b
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 * 
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 * 
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 *   Purpose
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 *   =======
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 *
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 *   sp_strsv() solves one of the systems of equations   
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 *       A*x = b,   or   A'*x = b,
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 *   where b and x are n element vectors and A is a sparse unit , or   
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 *   non-unit, upper or lower triangular matrix.   
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 *   No test for singularity or near-singularity is included in this   
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 *   routine. Such tests must be performed before calling this routine.   
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 *
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 *   Parameters   
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 *   ==========   
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 *
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 *   uplo   - (input) char*
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 *            On entry, uplo specifies whether the matrix is an upper or   
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 *             lower triangular matrix as follows:   
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 *                uplo = 'U' or 'u'   A is an upper triangular matrix.   
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 *                uplo = 'L' or 'l'   A is a lower triangular matrix.   
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 *
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 *   trans  - (input) char*
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 *             On entry, trans specifies the equations to be solved as   
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 *             follows:   
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 *                trans = 'N' or 'n'   A*x = b.   
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 *                trans = 'T' or 't'   A'*x = b.
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 *                trans = 'C' or 'c'   A'*x = b.   
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 *
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 *   diag   - (input) char*
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 *             On entry, diag specifies whether or not A is unit   
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 *             triangular as follows:   
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 *                diag = 'U' or 'u'   A is assumed to be unit triangular.   
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 *                diag = 'N' or 'n'   A is not assumed to be unit   
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 *                                    triangular.   
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 *	     
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 *   L       - (input) SuperMatrix*
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 *	       The factor L from the factorization Pr*A*Pc=L*U. Use
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 *             compressed row subscripts storage for supernodes,
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 *             i.e., L has types: Stype = SC, Dtype = SLU_S, Mtype = TRLU.
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 *
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 *   U       - (input) SuperMatrix*
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 *	        The factor U from the factorization Pr*A*Pc=L*U.
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 *	        U has types: Stype = NC, Dtype = SLU_S, Mtype = TRU.
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 *    
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 *   x       - (input/output) float*
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 *             Before entry, the incremented array X must contain the n   
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 *             element right-hand side vector b. On exit, X is overwritten 
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 *             with the solution vector x.
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 *
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 *   info    - (output) int*
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 *             If *info = -i, the i-th argument had an illegal value.
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 * 
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 */
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int
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sp_strsv(char *uplo, char *trans, char *diag, SuperMatrix *L, 
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         SuperMatrix *U, float *x, SuperLUStat_t *stat, int *info)
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{
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#ifdef _CRAY
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    _fcd ftcs1 = _cptofcd("L", strlen("L")),
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	 ftcs2 = _cptofcd("N", strlen("N")),
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	 ftcs3 = _cptofcd("U", strlen("U"));
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#endif
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    SCformat *Lstore;
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    NCformat *Ustore;
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    float   *Lval, *Uval;
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    int incx = 1, incy = 1;
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    float alpha = 1.0, beta = 1.0;
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    int nrow;
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    int fsupc, nsupr, nsupc, luptr, istart, irow;
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    int i, k, iptr, jcol;
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    float *work;
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    flops_t solve_ops;
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    /* Test the input parameters */
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    *info = 0;
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    if ( !lsame_(uplo,"L") && !lsame_(uplo, "U") ) *info = -1;
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    else if ( !lsame_(trans, "N") && !lsame_(trans, "T") && 
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              !lsame_(trans, "C")) *info = -2;
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    else if ( !lsame_(diag, "U") && !lsame_(diag, "N") ) *info = -3;
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    else if ( L->nrow != L->ncol || L->nrow < 0 ) *info = -4;
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    else if ( U->nrow != U->ncol || U->nrow < 0 ) *info = -5;
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    if ( *info ) {
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	i = -(*info);
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	xerbla_("sp_strsv", &i);
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	return 0;
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    }
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    Lstore = L->Store;
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    Lval = Lstore->nzval;
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    Ustore = U->Store;
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    Uval = Ustore->nzval;
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    solve_ops = 0;
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    if ( !(work = floatCalloc(L->nrow)) )
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	ABORT("Malloc fails for work in sp_strsv().");
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    if ( lsame_(trans, "N") ) {	/* Form x := inv(A)*x. */
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	if ( lsame_(uplo, "L") ) {
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	    /* Form x := inv(L)*x */
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    	    if ( L->nrow == 0 ) return 0; /* Quick return */
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	    for (k = 0; k <= Lstore->nsuper; k++) {
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		fsupc = L_FST_SUPC(k);
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		istart = L_SUB_START(fsupc);
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		nsupr = L_SUB_START(fsupc+1) - istart;
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		nsupc = L_FST_SUPC(k+1) - fsupc;
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		luptr = L_NZ_START(fsupc);
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		nrow = nsupr - nsupc;
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	        solve_ops += nsupc * (nsupc - 1);
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	        solve_ops += 2 * nrow * nsupc;
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		if ( nsupc == 1 ) {
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		    for (iptr=istart+1; iptr < L_SUB_START(fsupc+1); ++iptr) {
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			irow = L_SUB(iptr);
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			++luptr;
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			x[irow] -= x[fsupc] * Lval[luptr];
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		    }
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		} else {
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#ifdef USE_VENDOR_BLAS
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#ifdef _CRAY
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		    STRSV(ftcs1, ftcs2, ftcs3, &nsupc, &Lval[luptr], &nsupr,
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		       	&x[fsupc], &incx);
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		    SGEMV(ftcs2, &nrow, &nsupc, &alpha, &Lval[luptr+nsupc], 
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		       	&nsupr, &x[fsupc], &incx, &beta, &work[0], &incy);
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#else
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		    strsv_("L", "N", "U", &nsupc, &Lval[luptr], &nsupr,
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		       	&x[fsupc], &incx);
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		    sgemv_("N", &nrow, &nsupc, &alpha, &Lval[luptr+nsupc], 
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		       	&nsupr, &x[fsupc], &incx, &beta, &work[0], &incy);
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#endif
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#else
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		    slsolve ( nsupr, nsupc, &Lval[luptr], &x[fsupc]);
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		    smatvec ( nsupr, nsupr-nsupc, nsupc, &Lval[luptr+nsupc],
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                             &x[fsupc], &work[0] );
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#endif		
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		    iptr = istart + nsupc;
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		    for (i = 0; i < nrow; ++i, ++iptr) {
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			irow = L_SUB(iptr);
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			x[irow] -= work[i];	/* Scatter */
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			work[i] = 0.0;
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		    }
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	 	}
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	    } /* for k ... */
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	} else {
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	    /* Form x := inv(U)*x */
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	    if ( U->nrow == 0 ) return 0; /* Quick return */
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	    for (k = Lstore->nsuper; k >= 0; k--) {
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	    	fsupc = L_FST_SUPC(k);
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	    	nsupr = L_SUB_START(fsupc+1) - L_SUB_START(fsupc);
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	    	nsupc = L_FST_SUPC(k+1) - fsupc;
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	    	luptr = L_NZ_START(fsupc);
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    	        solve_ops += nsupc * (nsupc + 1);
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		if ( nsupc == 1 ) {
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		    x[fsupc] /= Lval[luptr];
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		    for (i = U_NZ_START(fsupc); i < U_NZ_START(fsupc+1); ++i) {
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			irow = U_SUB(i);
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			x[irow] -= x[fsupc] * Uval[i];
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		    }
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		} else {
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#ifdef USE_VENDOR_BLAS
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#ifdef _CRAY
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		    STRSV(ftcs3, ftcs2, ftcs2, &nsupc, &Lval[luptr], &nsupr,
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		       &x[fsupc], &incx);
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#else
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		    strsv_("U", "N", "N", &nsupc, &Lval[luptr], &nsupr,
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                           &x[fsupc], &incx);
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#endif
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#else		
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		    susolve ( nsupr, nsupc, &Lval[luptr], &x[fsupc] );
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#endif		
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		    for (jcol = fsupc; jcol < L_FST_SUPC(k+1); jcol++) {
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		        solve_ops += 2*(U_NZ_START(jcol+1) - U_NZ_START(jcol));
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		    	for (i = U_NZ_START(jcol); i < U_NZ_START(jcol+1); 
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				i++) {
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			    irow = U_SUB(i);
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			    x[irow] -= x[jcol] * Uval[i];
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		    	}
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                    }
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		}
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	    } /* for k ... */
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	}
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    } else { /* Form x := inv(A')*x */
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	if ( lsame_(uplo, "L") ) {
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	    /* Form x := inv(L')*x */
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    	    if ( L->nrow == 0 ) return 0; /* Quick return */
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	    for (k = Lstore->nsuper; k >= 0; --k) {
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	    	fsupc = L_FST_SUPC(k);
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	    	istart = L_SUB_START(fsupc);
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	    	nsupr = L_SUB_START(fsupc+1) - istart;
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	    	nsupc = L_FST_SUPC(k+1) - fsupc;
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	    	luptr = L_NZ_START(fsupc);
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		solve_ops += 2 * (nsupr - nsupc) * nsupc;
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		for (jcol = fsupc; jcol < L_FST_SUPC(k+1); jcol++) {
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		    iptr = istart + nsupc;
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		    for (i = L_NZ_START(jcol) + nsupc; 
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				i < L_NZ_START(jcol+1); i++) {
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			irow = L_SUB(iptr);
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			x[jcol] -= x[irow] * Lval[i];
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			iptr++;
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		    }
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		}
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		if ( nsupc > 1 ) {
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		    solve_ops += nsupc * (nsupc - 1);
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#ifdef _CRAY
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                    ftcs1 = _cptofcd("L", strlen("L"));
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                    ftcs2 = _cptofcd("T", strlen("T"));
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                    ftcs3 = _cptofcd("U", strlen("U"));
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		    STRSV(ftcs1, ftcs2, ftcs3, &nsupc, &Lval[luptr], &nsupr,
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			&x[fsupc], &incx);
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#else
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		    strsv_("L", "T", "U", &nsupc, &Lval[luptr], &nsupr,
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			&x[fsupc], &incx);
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#endif
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		}
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	    }
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	} else {
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	    /* Form x := inv(U')*x */
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	    if ( U->nrow == 0 ) return 0; /* Quick return */
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	    for (k = 0; k <= Lstore->nsuper; k++) {
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	    	fsupc = L_FST_SUPC(k);
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	    	nsupr = L_SUB_START(fsupc+1) - L_SUB_START(fsupc);
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	    	nsupc = L_FST_SUPC(k+1) - fsupc;
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	    	luptr = L_NZ_START(fsupc);
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		for (jcol = fsupc; jcol < L_FST_SUPC(k+1); jcol++) {
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		    solve_ops += 2*(U_NZ_START(jcol+1) - U_NZ_START(jcol));
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		    for (i = U_NZ_START(jcol); i < U_NZ_START(jcol+1); i++) {
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			irow = U_SUB(i);
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			x[jcol] -= x[irow] * Uval[i];
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		    }
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		}
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		solve_ops += nsupc * (nsupc + 1);
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		if ( nsupc == 1 ) {
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		    x[fsupc] /= Lval[luptr];
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		} else {
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#ifdef _CRAY
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                    ftcs1 = _cptofcd("U", strlen("U"));
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                    ftcs2 = _cptofcd("T", strlen("T"));
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                    ftcs3 = _cptofcd("N", strlen("N"));
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		    STRSV( ftcs1, ftcs2, ftcs3, &nsupc, &Lval[luptr], &nsupr,
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			    &x[fsupc], &incx);
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#else
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		    strsv_("U", "T", "N", &nsupc, &Lval[luptr], &nsupr,
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			    &x[fsupc], &incx);
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#endif
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		}
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	    } /* for k ... */
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	}
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    }
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    stat->ops[SOLVE] += solve_ops;
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    SUPERLU_FREE(work);
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    return 0;
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}
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/*! \brief Performs one of the matrix-vector operations y := alpha*A*x + beta*y,   or   y := alpha*A'*x + beta*y,   
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 *
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 * 
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 *   Purpose   
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 *   =======   
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 *
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 *   sp_sgemv()  performs one of the matrix-vector operations   
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 *      y := alpha*A*x + beta*y,   or   y := alpha*A'*x + beta*y,   
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 *   where alpha and beta are scalars, x and y are vectors and A is a
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 *   sparse A->nrow by A->ncol matrix.   
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 *
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 *   Parameters   
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 *   ==========   
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 *
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 *   TRANS  - (input) char*
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 *            On entry, TRANS specifies the operation to be performed as   
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 *            follows:   
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 *               TRANS = 'N' or 'n'   y := alpha*A*x + beta*y.   
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 *               TRANS = 'T' or 't'   y := alpha*A'*x + beta*y.   
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 *               TRANS = 'C' or 'c'   y := alpha*A'*x + beta*y.   
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 *
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 *   ALPHA  - (input) float
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 *            On entry, ALPHA specifies the scalar alpha.   
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 *
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 *   A      - (input) SuperMatrix*
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 *            Matrix A with a sparse format, of dimension (A->nrow, A->ncol).
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 *            Currently, the type of A can be:
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 *                Stype = NC or NCP; Dtype = SLU_S; Mtype = GE. 
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 *            In the future, more general A can be handled.
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 *
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 *   X      - (input) float*, array of DIMENSION at least   
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 *            ( 1 + ( n - 1 )*abs( INCX ) ) when TRANS = 'N' or 'n'   
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 *            and at least   
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 *            ( 1 + ( m - 1 )*abs( INCX ) ) otherwise.   
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 *            Before entry, the incremented array X must contain the   
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 *            vector x.   
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 *
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 *   INCX   - (input) int
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 *            On entry, INCX specifies the increment for the elements of   
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 *            X. INCX must not be zero.   
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 *
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 *   BETA   - (input) float
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 *            On entry, BETA specifies the scalar beta. When BETA is   
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 *            supplied as zero then Y need not be set on input.   
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 *
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 *   Y      - (output) float*,  array of DIMENSION at least   
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 *            ( 1 + ( m - 1 )*abs( INCY ) ) when TRANS = 'N' or 'n'   
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 *            and at least   
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 *            ( 1 + ( n - 1 )*abs( INCY ) ) otherwise.   
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 *            Before entry with BETA non-zero, the incremented array Y   
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 *            must contain the vector y. On exit, Y is overwritten by the 
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 *            updated vector y.
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 *	     
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 *   INCY   - (input) int
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 *            On entry, INCY specifies the increment for the elements of   
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 *            Y. INCY must not be zero.   
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 *
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 *   ==== Sparse Level 2 Blas routine.   
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 * 
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 */
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int
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sp_sgemv(char *trans, float alpha, SuperMatrix *A, float *x, 
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	 int incx, float beta, float *y, int incy)
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{
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    /* Local variables */
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    NCformat *Astore;
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    float   *Aval;
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    int info;
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    float temp;
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    int lenx, leny, i, j, irow;
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    int iy, jx, jy, kx, ky;
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    int notran;
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    notran = lsame_(trans, "N");
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    Astore = A->Store;
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    Aval = Astore->nzval;
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    /* Test the input parameters */
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    info = 0;
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    if ( !notran && !lsame_(trans, "T") && !lsame_(trans, "C")) info = 1;
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    else if ( A->nrow < 0 || A->ncol < 0 ) info = 3;
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    else if (incx == 0) info = 5;
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    else if (incy == 0)	info = 8;
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    if (info != 0) {
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	xerbla_("sp_sgemv ", &info);
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	return 0;
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    }
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    /* Quick return if possible. */
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    if (A->nrow == 0 || A->ncol == 0 || (alpha == 0. && beta == 1.))
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	return 0;
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    /* Set  LENX  and  LENY, the lengths of the vectors x and y, and set 
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       up the start points in  X  and  Y. */
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    if (lsame_(trans, "N")) {
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	lenx = A->ncol;
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	leny = A->nrow;
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    } else {
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	lenx = A->nrow;
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	leny = A->ncol;
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    }
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    if (incx > 0) kx = 0;
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    else kx =  - (lenx - 1) * incx;
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    if (incy > 0) ky = 0;
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    else ky =  - (leny - 1) * incy;
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    /* Start the operations. In this version the elements of A are   
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       accessed sequentially with one pass through A. */
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    /* First form  y := beta*y. */
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    if (beta != 1.) {
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	if (incy == 1) {
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	    if (beta == 0.)
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		for (i = 0; i < leny; ++i) y[i] = 0.;
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	    else
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		for (i = 0; i < leny; ++i) y[i] = beta * y[i];
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	} else {
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	    iy = ky;
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	    if (beta == 0.)
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		for (i = 0; i < leny; ++i) {
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		    y[iy] = 0.;
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		    iy += incy;
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		}
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	    else
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		for (i = 0; i < leny; ++i) {
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		    y[iy] = beta * y[iy];
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		    iy += incy;
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		}
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	}
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    }
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    if (alpha == 0.) return 0;
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    if ( notran ) {
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	/* Form  y := alpha*A*x + y. */
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	jx = kx;
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	if (incy == 1) {
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	    for (j = 0; j < A->ncol; ++j) {
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		if (x[jx] != 0.) {
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		    temp = alpha * x[jx];
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		    for (i = Astore->colptr[j]; i < Astore->colptr[j+1]; ++i) {
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			irow = Astore->rowind[i];
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			y[irow] += temp * Aval[i];
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		    }
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		}
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		jx += incx;
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	    }
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	} else {
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	    ABORT("Not implemented.");
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	}
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    } else {
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	/* Form  y := alpha*A'*x + y. */
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	jy = ky;
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	if (incx == 1) {
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	    for (j = 0; j < A->ncol; ++j) {
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		temp = 0.;
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		for (i = Astore->colptr[j]; i < Astore->colptr[j+1]; ++i) {
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		    irow = Astore->rowind[i];
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		    temp += Aval[i] * x[irow];
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		}
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		y[jy] += alpha * temp;
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		jy += incy;
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	    }
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	} else {
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	    ABORT("Not implemented.");
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	}
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    }
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    return 0;
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} /* sp_sgemv */
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