#include "BSprivate.h"

/*@ BSforward1 - Forward triangular matrix multiplication on a single vector

    Input Parameters:
.   A - The sparse matrix
.   x - The rhs
.   comm - The communication structure for A
.   procinfo - the usual processor information

    Output Parameters:
.   b - on exit contains A*x

    Returns:
    void

	Notes:
    We assume that A has no i-nodes or cliques

 @*/
void BSforward1(BSpar_mat *A, FLOAT *x, FLOAT *b,
		BScomm *comm, BSprocinfo *procinfo)
{
	BMphase *to_phase, *from_phase;
	BMmsg *msg;
	int	i, j, k;
	int	cl_ind, in_ind, symmetric;
	int	count, size, ind;
	int *row;
	FLOAT *nz;
	BScl_2_inode *clique2inode;
	BSnumbering *color2clique;
	BSinode *inodes;
	int	*data_ptr, msg_len;
	FLOAT *msg_buf;
	FLOAT	t;
	int *gnum, *iperm;

    /* Is the symmetric data structure used? */
	symmetric = A->icc_storage;

	color2clique = A->color2clique;
	clique2inode = A->clique2inode;
	inodes = A->inodes->list;
	gnum = A->global_row_num->numbers;
	iperm = A->inv_perm->perm;

	/* post for all messages */
	BMinit_comp_msg(comm->from_msg,procinfo); CHKERR(0);

	if(symmetric) {
		if (A->save_diag == NULL) {
			/* because we know the diagonal is ones, initialize b to x */
			for (i=0;i<A->num_rows;i++) b[i] = x[i];
		} else {
			for (i=0;i<A->num_rows;i++) b[i] = A->save_diag[i]*x[i];
		}
	}

	/* first send my messages */
	for (i=0;i<color2clique->length-1;i++) {

		if(!symmetric) {
			/* first multiply with the scaled diag, if any (ILU) */
			for (cl_ind=color2clique->numbers[i];
				cl_ind<color2clique->numbers[i+1]; cl_ind++) {
				if (procinfo->my_id == clique2inode->proc[cl_ind]) {
					ind = clique2inode->d_mats[cl_ind].local_ind;
					if (A->scale_diag == NULL)
						b[ind] = A->diag[ind]*x[ind];
					else
						if (A->diag[ind] > 0.0)
							b[ind] = x[ind];
						else if (A->diag[ind] < 0.0)
							b[ind] = -x[ind];
						else
							b[ind] = 0.0;
				}
			}
		}

		/* now send my messages */
		to_phase = BMget_phase(comm->to_msg,i); CHKERR(0);
		msg = NULL;
		while ((msg = BMnext_msg(to_phase,msg)) != NULL) {
			CHKERR(0);
			msg_buf = (FLOAT *) BMget_msg_ptr(msg); CHKERR(0);
			data_ptr = BMget_user(msg,&msg_len); CHKERR(0);
			for (j=0;j<msg_len;j++) {
				msg_buf[j] = x[data_ptr[j]];
			}
			BMsendf_msg(msg,procinfo); CHKERR(0);
		}
		CHKERR(0);
	}

	/* do some local work */
	for (i=0;i<color2clique->length-1;i++) {
		for (cl_ind=color2clique->numbers[i];
			cl_ind<color2clique->numbers[i+1];cl_ind++) {
			if (procinfo->my_id == clique2inode->proc[cl_ind]) {
				/* only do the strictly lower triangular part */
				/* we ASSUME the diagonal is all 1's */
				/* and it is taken care of above */
				/* now, multiply the inodes */
				in_ind=clique2inode->inode_index[cl_ind];
				size = inodes[in_ind].length;
				if (size > 0) {
					ind = clique2inode->d_mats[cl_ind].local_ind;
					row = inodes[in_ind].row_num;
					nz = inodes[in_ind].nz;
					t = x[ind];
					for (k=0;k<size;k++) b[row[k]] += nz[k]*t;
				}
			}
		}
	}

	/* receive my messages and do non-local work */
	for (i=0;i<color2clique->length-1;i++) {
		from_phase = BMget_phase(comm->from_msg,i); CHKERR(0);
		while ((msg = BMrecv_msg(from_phase)) != NULL) {
			CHKERR(0);
			msg_buf = (FLOAT *) BMget_msg_ptr(msg); CHKERR(0);
			data_ptr = BMget_user(msg,&msg_len); CHKERR(0);
			count = 0;
			for (cl_ind=data_ptr[0];cl_ind<=data_ptr[1];cl_ind++) {
				in_ind=clique2inode->inode_index[cl_ind];
				size = inodes[in_ind].length;
				if (size > 0) {
					row = inodes[in_ind].row_num;
					nz = inodes[in_ind].nz;
					t = msg_buf[count];
					for (k=0;k<size;k++) b[row[k]] += nz[k]*t;
				}
				count++;
			}
			BMfree_msg(msg); CHKERR(0);
		}
		CHKERR(0);
	}
	/* wait for all of the sent messages to finish */
	BMfinish_comp_msg(comm->to_msg,procinfo); CHKERR(0);
	if(symmetric) {
		MLOG_flop((2*A->local_nnz));
	} else {
		MLOG_flop((4*A->local_nnz-2*A->num_rows));
	}

}