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placer1: Experiment with adding 'constraint distance' metric

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Signed-off-by: David Shah <davey1576@gmail.com>
This commit is contained in:
David Shah 2018-08-03 17:42:07 +02:00
parent 03c2d22fff
commit aa8435df21
1 changed files with 11 additions and 2 deletions
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13
common/placer1.cc
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@ -348,6 +348,10 @@ private:
if (other_cell->belStrength > STRENGTH_WEAK) if (other_cell->belStrength > STRENGTH_WEAK)
return false; return false;
} }
int old_dist = get_constraints_distance(ctx, cell);
int new_dist;
if (other != IdString())
old_dist += get_constraints_distance(ctx, other_cell);
wirelen_t new_metric = 0, delta; wirelen_t new_metric = 0, delta;
ctx->unbindBel(oldBel); ctx->unbindBel(oldBel);
if (other != IdString()) { if (other != IdString()) {
@ -386,7 +390,12 @@ private:
new_metric += net_new_wl; new_metric += net_new_wl;
new_lengths.push_back(std::make_pair(net->name, net_new_wl)); new_lengths.push_back(std::make_pair(net->name, net_new_wl));
} }
new_dist = get_constraints_distance(ctx, cell);
if (other != IdString())
new_dist += get_constraints_distance(ctx, other_cell);
delta = new_metric - curr_metric; delta = new_metric - curr_metric;
delta += (1 / temp) * (new_dist - old_dist);
n_move++; n_move++;
// SA acceptance criterea // SA acceptance criterea
if (delta < 0 || (temp > 1e-6 && (ctx->rng() / float(0x3fffffff)) <= std::exp(-delta / temp))) { if (delta < 0 || (temp > 1e-6 && (ctx->rng() / float(0x3fffffff)) <= std::exp(-delta / temp))) {
@ -447,8 +456,8 @@ private:
std::unordered_set<BelId> locked_bels; std::unordered_set<BelId> locked_bels;
bool require_legal = false; bool require_legal = false;
const float legalise_temp = 1; const float legalise_temp = 1;
const float post_legalise_temp = 20; const float post_legalise_temp = 10;
const float post_legalise_dia_scale = 2; const float post_legalise_dia_scale = 1.5;
}; };
bool placer1(Context *ctx) bool placer1(Context *ctx)