/* make a random move out of the above */
NPE_t *make_random_move(NPE_t *expr)
{
int i, move, count = 0, done = FALSE, m3_count;
NPE_t *copy = NPE_duplicate(expr);
while (!done && count < MAX_MOVES) {
/* choose one of three moves */
move = rand_upto(3);
switch(move) {
case 0: /* swap adjacent units */
/* leave the unit last in the NPE */
i = rand_upto(expr->n_units-1);
#if VERBOSE > 2
fprintf(stdout, "making M1 at %d\n", expr->unit_pos[i]);
#endif
NPE_swap_units(copy, expr->unit_pos[i]);
done = TRUE;
break;
case 1: /* invert an arbitrary chain */
i = rand_upto(expr->n_chains);
#if VERBOSE > 2
fprintf(stdout, "making M2 at %d\n", expr->chain_pos[i]);
#endif
NPE_invert_chain(copy, expr->chain_pos[i]);
done = TRUE;
break;
case 2: /* swap a unit and an adjacent cut_type */
m3_count = 0;
while (!done && m3_count < MAX_MOVES) {
i = rand_upto(expr->n_flips);
#if VERBOSE > 2
fprintf(stdout, "making M3 at %d\n", expr->flip_pos[i]);
#endif
done = NPE_swap_cut_unit(copy, expr->flip_pos[i]);
m3_count++;
}
break;
default:
fatal("unknown move type\n");
break;
}
count++;
}
if (count == MAX_MOVES) {
char msg[STR_SIZE];
sprintf(msg, "tried %d moves, now giving up\n", MAX_MOVES);
fatal(msg);
}
return copy;
}
/*
* floorplanning using simulated annealing.
* precondition: flp is a pre-allocated placeholder.
* returns the number of compacted blocks in the selected
* floorplan
*/
int floorplan(flp_t *flp, flp_desc_t *flp_desc,
RC_model_t *model, double *power)
{
NPE_t *expr, *next, *best; /* Normalized Polish Expressions */
tree_node_stack_t *stack; /* for NPE evaluation */
tree_node_t *root; /* shape curve tree */
double cost, new_cost, best_cost, sum_cost, T, Tcold;
int i, steps, downs, n, rejects, compacted, rim_blocks = 0;
int original_n = flp->n_units;
int wrap_l2;
/* to maintain the order of power values during
* the compaction/shifting around of blocks
*/
double *tpower = hotspot_vector(model);
/* shortcut */
flp_config_t cfg = flp_desc->config;
/*
* make the rim strips disappear for slicing tree
* purposes. can be restored at the end
*/
if (cfg.model_rim)
flp->n_units = (flp->n_units - 2) / 3;
/* wrap L2 around? */
wrap_l2 = FALSE;
if (cfg.wrap_l2 &&
!strcasecmp(flp_desc->units[flp_desc->n_units-1].name, cfg.l2_label)) {
wrap_l2 = TRUE;
/* make L2 disappear too */
flp_desc->n_units--;
flp->n_units -= (L2_ARMS+1);
}
/* initialization */
expr = NPE_get_initial(flp_desc);
stack = new_tree_node_stack();
init_rand();
/* convert NPE to flp */
root = tree_from_NPE(flp_desc, stack, expr);
/* compacts too small dead blocks */
compacted = tree_to_flp(root, flp, TRUE, cfg.compact_ratio);
/* update the tpower vector according to the compaction */
trim_hotspot_vector(model, tpower, power, flp->n_units, compacted);
free_tree(root);
if(wrap_l2)
flp_wrap_l2(flp, flp_desc);
if(cfg.model_rim)
rim_blocks = flp_wrap_rim(flp, cfg.rim_thickness);
resize_thermal_model(model, flp->n_units);
#if VERBOSE > 2
print_flp(flp);
#endif
cost = flp_evaluate_metric(flp, model, tpower, cfg.lambdaA, cfg.lambdaT, cfg.lambdaW);
/* restore the compacted blocks */
restore_dead_blocks(flp, flp_desc, compacted, wrap_l2, cfg.model_rim, rim_blocks);
best = NPE_duplicate(expr); /* best till now */
best_cost = cost;
/* simulated annealing */
steps = 0;
/* initial annealing temperature */
T = -cfg.Davg / log(cfg.P0);
/*
* final annealing temperature - we stop when there
* are fewer than (1-cfg.Rreject) accepts.
* of those accepts, assuming half are uphill moves,
* we want the temperature so that the probability
* of accepting uphill moves is as low as
* (1-cfg.Rreject)/2.
*/
Tcold = -cfg.Davg / log ((1.0 - cfg.Rreject) / 2.0);
#if VERBOSE > 0
fprintf(stdout, "initial cost: %g\tinitial T: %g\tfinal T: %g\n", cost, T, Tcold);
#endif
/*
* stop annealing if temperature has cooled down enough or
* max no. of iterations have been tried
*/
while (T >= Tcold && steps < cfg.Nmax) {
/* shortcut */
n = cfg.Kmoves * flp->n_units;
i = downs = rejects = 0;
sum_cost = 0;
/* try enough total or downhill moves per T */
while ((i < 2 * n) && (downs < n)) {
next = make_random_move(expr);
/* convert NPE to flp */
root = tree_from_NPE(flp_desc, stack, next);
compacted = tree_to_flp(root, flp, TRUE, cfg.compact_ratio);
/* update the tpower vector according to the compaction */
trim_hotspot_vector(model, tpower, power, flp->n_units, compacted);
free_tree(root);
if(wrap_l2)
flp_wrap_l2(flp, flp_desc);
if(cfg.model_rim)
rim_blocks = flp_wrap_rim(flp, cfg.rim_thickness);
resize_thermal_model(model, flp->n_units);
#if VERBOSE > 2
print_flp(flp);
#endif
new_cost = flp_evaluate_metric(flp, model, tpower, cfg.lambdaA, cfg.lambdaT, cfg.lambdaW);
restore_dead_blocks(flp, flp_desc, compacted, wrap_l2, cfg.model_rim, rim_blocks);
#if VERBOSE > 1
fprintf(stdout, "count: %d\tdowns: %d\tcost: %g\t",
i, downs, new_cost);
#endif
/* move accepted? */
if (new_cost < cost || /* downhill always accepted */
/* boltzmann probability function */
rand_fraction() < exp(-(new_cost-cost)/T)) {
free_NPE(expr);
expr = next;
/* downhill move */
if (new_cost < cost) {
downs++;
/* found new best */
if (new_cost < best_cost) {
free_NPE(best);
best = NPE_duplicate(expr);
best_cost = new_cost;
}
}
#if VERBOSE > 1
fprintf(stdout, "accepted\n");
#endif
cost = new_cost;
sum_cost += cost;
} else { /* rejected move */
rejects++;
free_NPE(next);
#if VERBOSE > 1
fprintf(stdout, "rejected\n");
#endif
}
i++;
}
#if VERBOSE > 0
fprintf(stdout, "step: %d\tT: %g\ttries: %d\taccepts: %d\trejects: %d\t",
steps, T, i, (i-rejects), rejects);
fprintf(stdout, "avg. cost: %g\tbest cost: %g\n",
(i-rejects)?(sum_cost / (i-rejects)):sum_cost, best_cost);
#endif
/* stop annealing if there are too little accepts */
if(((double)rejects/i) > cfg.Rreject)
break;
/* annealing schedule */
T *= cfg.Rcool;
steps++;
}
/* best floorplan found */
root = tree_from_NPE(flp_desc, stack, best);
#if VERBOSE > 0
{
int pos = min_area_pos(root->curve);
print_tree_relevant(root, pos, flp_desc);
}
#endif
compacted = tree_to_flp(root, flp, TRUE, cfg.compact_ratio);
/* update the power vector according to the compaction */
trim_hotspot_vector(model, power, power, flp->n_units, compacted);
free_tree(root);
/* restore L2 and rim */
if(wrap_l2) {
flp_wrap_l2(flp, flp_desc);
flp_desc->n_units++;
}
if(cfg.model_rim)
rim_blocks = flp_wrap_rim(flp, cfg.rim_thickness);
resize_thermal_model(model, flp->n_units);
#if VERBOSE > 2
print_flp(flp);
#endif
free_NPE(expr);
free_NPE(best);
free_tree_node_stack(stack);
free_dvector(tpower);
/*
* return the number of blocks compacted finally
* so that any deallocator can take care of memory
* accordingly.
*/
return (original_n - flp->n_units);
}