caiyu/nextpnr
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

placer1: Tweaking temperature

Browse Source 
Signed-off-by: David Shah <davey1576@gmail.com>
This commit is contained in:
David Shah 2018-12-09 10:38:08 +00:00 committed by David Shah
parent 0d80181c5e
commit 3650c8a0e7
1 changed files with 14 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
common/placer1.cc
View File

@ -197,7 +197,7 @@ class SAPlacer
wirelen_t min_wirelen = curr_wirelen_cost; wirelen_t min_wirelen = curr_wirelen_cost;
int n_no_progress = 0; int n_no_progress = 0;
temp = 10000; temp = 1;
// Main simulated annealing loop // Main simulated annealing loop
for (int iter = 1;; iter++) { for (int iter = 1;; iter++) {
@ -232,7 +232,7 @@ class SAPlacer
else else
n_no_progress++; n_no_progress++;
if (temp <= 1e-3 && n_no_progress >= 5) { if (temp <= 1e-7 && n_no_progress >= 5) {
log_info(" at iteration #%d: temp = %f, timing cost = " log_info(" at iteration #%d: temp = %f, timing cost = "
"%.0f, wirelen = %.0f \n", "%.0f, wirelen = %.0f \n",
iter, temp, double(curr_timing_cost), double(curr_wirelen_cost)); iter, temp, double(curr_timing_cost), double(curr_wirelen_cost));
@ -245,7 +245,12 @@ class SAPlacer
double upper = 0.6, lower = 0.4; double upper = 0.6, lower = 0.4;
if (curr_wirelen_cost < 0.95 * avg_wirelen && curr_wirelen_cost > 0) { if (ctx->verbose)
log("iter #%d: temp = %f, timing cost = "
"%.0f, wirelen = %.0f, dia = %d, Ra = %.02f \n",
iter, temp, double(curr_timing_cost), double(curr_wirelen_cost), diameter, Raccept);
if (curr_wirelen_cost < 0.95 * avg_wirelen && curr_wirelen_cost > 0) {
avg_wirelen = 0.8 * avg_wirelen + 0.2 * curr_wirelen_cost; avg_wirelen = 0.8 * avg_wirelen + 0.2 * curr_wirelen_cost;
} else { } else {
if (Raccept >= 0.8) { if (Raccept >= 0.8) {
@ -276,7 +281,7 @@ class SAPlacer
autoplaced.push_back(cell.second); autoplaced.push_back(cell.second);
} }
temp = post_legalise_temp; temp = post_legalise_temp;
diameter *= post_legalise_dia_scale; diameter = std::min<int>(M, diameter * post_legalise_dia_scale);
ctx->shuffle(autoplaced); ctx->shuffle(autoplaced);
// Legalisation is a big change so force a slack redistribution here // Legalisation is a big change so force a slack redistribution here
@ -435,7 +440,7 @@ class SAPlacer
delta += (cfg.constraintWeight / temp) * (new_dist - old_dist) / last_wirelen_cost; delta += (cfg.constraintWeight / temp) * (new_dist - old_dist) / last_wirelen_cost;
n_move++; n_move++;
// SA acceptance criterea // SA acceptance criterea
if (delta < 0 || (temp > 1e-6 && (ctx->rng() / float(0x0fffffff)) <= std::exp(-100 * delta / temp))) { if (delta < 0 || (temp > 1e-8 && (ctx->rng() / float(0x3fffffff)) <= std::exp(-delta / temp))) {
n_accept++; n_accept++;
} else { } else {
if (other_cell != nullptr) if (other_cell != nullptr)
@ -676,7 +681,7 @@ class SAPlacer
NetCriticalityMap net_crit; NetCriticalityMap net_crit;
Context *ctx; Context *ctx;
float temp = 1000; float temp = 10;
float crit_exp = 8; float crit_exp = 8;
float lambda = 0.5; float lambda = 0.5;
bool improved = false; bool improved = false;
@ -686,8 +691,8 @@ class SAPlacer
std::vector<std::vector<std::vector<std::vector<BelId>>>> fast_bels; std::vector<std::vector<std::vector<std::vector<BelId>>>> fast_bels;
std::unordered_set<BelId> locked_bels; std::unordered_set<BelId> locked_bels;
bool require_legal = true; bool require_legal = true;
const float legalise_temp = 1; const float legalise_temp = 0.00015;
const float post_legalise_temp = 10; const float post_legalise_temp = 0.0003;
const float post_legalise_dia_scale = 1.5; const float post_legalise_dia_scale = 1.5;
Placer1Cfg cfg; Placer1Cfg cfg;
}; };