int update_params(void)
{
int i;
SW_INS_PTR ptr;
double sum;
for (i = 0; i < occ_switch_tab_size; i++) {
ptr = occ_switches[i];
sum = 0.0;
while (ptr != NULL) {
sum += ptr->total_expect;
ptr = ptr->next;
}
if (sum != 0.0) {
ptr = occ_switches[i];
if (ptr->fixed > 0) continue;
while (ptr != NULL) {
if (ptr->fixed == 0) ptr->inside = ptr->total_expect / sum;
if (log_scale && ptr->inside < TINY_PROB) {
emit_error("Parameter being zero (-inf in log scale) -- %s",
prism_sw_ins_string(ptr->id));
RET_ERR(err_underflow);
}
ptr = ptr->next;
}
}
}
return BP_TRUE;
}
static int compute_gradient_scaling_log_exp(void) {
int i,k;
EG_PATH_PTR path_ptr;
EG_NODE_PTR eg_ptr,node_ptr;
SW_INS_PTR sw_ptr;
double q,r;
for (i = 0; i < sw_ins_tab_size; i++) {
switch_instances[i]->total_expect = 0.0;
switch_instances[i]->has_first_expectation = 0;
switch_instances[i]->first_expectation = 0.0;
}
for (i = 0; i < sorted_egraph_size; i++) {
sorted_expl_graph[i]->outside = 0.0;
sorted_expl_graph[i]->has_first_outside = 0;
sorted_expl_graph[i]->first_outside = 0.0;
}
for (i = 0; i < num_roots; i++) {
if (roots[i]->pid == -1) {
eg_ptr = expl_graph[roots[i]->id];
if (i == failure_root_index) {
eg_ptr->first_outside =
log(num_goals / (1.0 - exp(inside_failure)));
} else {
eg_ptr->first_outside =
log((double)(roots[i]->sgd_count)) - eg_ptr->inside;
}
eg_ptr->has_first_outside = 1;
eg_ptr->outside = 1.0;
}
}
/* sorted_expl_graph[to] must be a root node */
for (i = sorted_egraph_size - 1; i >= 0; i--) {
eg_ptr = sorted_expl_graph[i];
if (eg_ptr->visited == 0) continue;
/* First accumulate log-scale outside probabilities: */
if (!eg_ptr->has_first_outside) {
emit_internal_error("unexpected has_first_outside[%s]",
prism_goal_string(eg_ptr->id));
RET_INTERNAL_ERR;
} else if (!(eg_ptr->outside > 0.0)) {
emit_internal_error("unexpected outside[%s]",
prism_goal_string(eg_ptr->id));
RET_INTERNAL_ERR;
} else {
eg_ptr->outside = eg_ptr->first_outside + log(eg_ptr->outside);
}
path_ptr = sorted_expl_graph[i]->path_ptr;
while (path_ptr != NULL) {
q = sorted_expl_graph[i]->outside + path_ptr->inside;
for (k = 0; k < path_ptr->children_len; k++) {
node_ptr = path_ptr->children[k];
r = q - node_ptr->inside;
if (!node_ptr->has_first_outside) {
node_ptr->first_outside = r;
node_ptr->outside += 1.0;
node_ptr->has_first_outside = 1;
} else if (r - node_ptr->first_outside >= log(HUGE_PROB)) {
node_ptr->outside *= exp(node_ptr->first_outside - r);
node_ptr->first_outside = r;
node_ptr->outside += 1.0;
} else {
node_ptr->outside += exp(r - node_ptr->first_outside);
}
}
for (k = 0; k < path_ptr->sws_len; k++) {
sw_ptr = path_ptr->sws[k];
if (!sw_ptr->has_first_expectation) {
sw_ptr->first_expectation = q;
sw_ptr->total_expect += 1.0;
sw_ptr->has_first_expectation = 1;
} else if (q - sw_ptr->first_expectation >= log(HUGE_PROB)) {
sw_ptr->total_expect *= exp(sw_ptr->first_expectation - q);
sw_ptr->first_expectation = q;
sw_ptr->total_expect += 1.0;
} else {
sw_ptr->total_expect += exp(q - sw_ptr->first_expectation);
}
}
path_ptr = path_ptr->next;
}
}
/* unscale total_expect */
for (i = 0; i < sw_ins_tab_size; i++) {
sw_ptr = switch_instances[i];
if (!sw_ptr->has_first_expectation) continue;
if (!(sw_ptr->total_expect > 0.0)) {
emit_error("unexpected expectation for %s",prism_sw_ins_string(i));
RET_ERR(err_invalid_numeric_value);
}
sw_ptr->total_expect =
exp(sw_ptr->first_expectation + log(sw_ptr->total_expect));
}
for (i=0; i<occ_switch_tab_size; i++) {
sw_ptr = occ_switches[i];
while (sw_ptr!=NULL) {
sw_ptr->gradient = (sw_ptr->count - sw_ptr->total_expect) * sw_ptr->inside_h;
if (crf_penalty != 0.0) {
sw_ptr->gradient -= sw_ptr->inside * crf_penalty;
}
sw_ptr = sw_ptr->next;
}
}
return BP_TRUE;
}
