HotSpot Thermal Floorplan Solver Using Conjugate Gradient to Speed Up

Algorithm 2

: The SA thermal floorplan algorithm with the conjugate gradient thermal solver.

Require: cost(f) SA floorplan evaluate metric;
Ensure: optimal floorplan
1	rnorm = (r,r);
2	int Iter = 0;
3	double α, β, rp, rpold, bnorm, rnorm;
4	vector r, p, q, z;
5	initial T schedule;
6	/stop annealing if temperature has cooled down enough or max no. of iterations have been tried/
7	while (T ≥ Tcold && steps < cfg.Nmax) do
8	n = cfg.Kmoves ∗ flp− > n units;
9	i = downs = rejects = 0;
10	sumcost = 0;
11	/ try enough total or downhill moves per T /
12	while (do(i < 2 ∗ n)&&(downs < n))
13	make random move and data process to floorplan
14	new cost = floorplan evaluate metric;
15	// area (A), temperature (T), and wire length (W):
16	lambdaA A + lambdaT T + lambdaW W
17	reusing the T to be linear solver initial solution
18	if (new cost < cost ∥ rand fraction() < exp(−(new cost − cost)/T)) then
19	/ downhill always accepted /
20	or / Boltzmann probability function /
21	accepted new cost
22	else
23	rejects++;
24	end if
25	i++;
26	end while
27	/ stop annealing if there are too little accepts /
28	if((rejects/i) > cfg.Rreject)
29	break;
30	/ annealing schedule /
31	T= cfg.Rcool;;
32	steps++;
33	end while