/* $URL: svn+ssh://mrwhat@ssh.boim.com/home/mrwhat/svn/Walker/trunk/com/boim/walker/OptJansen.java $ $Id: OptJansen.java 411 2014-02-26 15:32:13Z mrwhat $ Front end to run simplex optimizer on JansenMetric. JansenMetric is specific to the Jansen linkage, and less generalized than the older one-size-fits-all WalkerMetric. It seems wise to keep the JansenLinkage class a little simpler, and put all the specific metric stuff in the new JansenMetric class. This version will just write plots directly to .svg files, instead of calling Octave for plotting. */ package com.boim.walker; import java.io.*; import com.boim.optimize.*; import com.boim.util.*; import java.util.*; public class OptJansen { //private BufferedWriter octIn; private static Random rand; public static void main(String[] args) { JansenLinkage linkage = new JansenLinkage(); linkage.scale(17.5/linkage._AC); JansenMetric metric = new JansenMetric(linkage); double[] x = metric.getState(); double[] seedState = x.clone(); System.out.println("input Configuration :"); metric._linkage.print(System.out); PrintStream maximaOut; try { maximaOut = new PrintStream(new File("maxima.dat")); } catch(Exception e){ maximaOut = System.out; } // A "BadConfigurationList" is also a great way to store a list of GOOD configurations. // use it to remember what configurations have already been reported, so that we don't // repeat outputs BadConfigurationList reported = new BadConfigurationList(); double reportedThresh = 0.5; // do not report if this close to a previous report NelderMeadSimplex opt = new NelderMeadSimplex(); opt._maxEval = 99999; opt._expand = 1.4; // expand a little slower, perhaps we'll do it more often //opt._startStep = 400; // smaller starting step double searchStep = 400; // initial step multiplier to use for large-scale search double checkStep = 5; // initial step multiplier used to re-check answers double recheckThresh = 0.2; // close enough on answer re-check, euclidean dist linkage lengths double best=1; int n=0; int nSkipped=0; boolean reset = false; // backdoor to reset linkage when debugging double changeProb = 0.3; double stepSD = 1; double gravity = 0.2; // value (0..1) for how much attraction there is to seed solution in search double scale = 0.8; // scale down "max" by this for every solution, to report after degenerate high score int nRechecks = 5; // number of times to verify an optimization int nFailedRechecks = 0; while(true) { x = randomize(x,changeProb,stepSD); // make sure a configuration is (locally) maximal before reporting it int nCheck = 0; double score = 0; double currentMaxima = 0; while (nCheck < nRechecks) { opt._startStep = searchStep; // initial step multiplier to use for large-scale search x = opt.optimize(metric,x); score = metric.metric(x); plotConfig(metric._linkage,n++,metric._desc); metric._prevMax = 1.0; // reset dump plots to show check progress if (Double.isNaN(score)) { reset = true; score=0; } System.out.format("%g/%g%n",score,best); if (score > currentMaxima) { currentMaxima = score; double checkDist = 0; double[] x0 = x.clone(); opt._startStep = checkStep; // small step to use for re-check search while ((nCheck <= nRechecks) && (checkDist < recheckThresh)) { x = randomize(x0,changeProb,0.05); // very small random tweak for re-check x = opt.optimize(metric,x); metric._prevMax = 1.0; // reset dump plots to show check progress checkDist = PointNode.dist(x,x0); nCheck++; } if (nCheck < nRechecks) {// re-check failed plotConfig(metric._linkage,n++,metric._desc); nCheck=0; nFailedRechecks++; currentMaxima=0; } } best *= scale; // let this shrink to "reset" occationally best=1; // show every "optimim", for now if (reset) { reset=false; metric._linkage.setDefault(); x = metric.getState(); best = 0.001; currentMaxima=0; } } //metric._linkage.print(System.out); //double score = metric.metric(x); // print out EVERY checked maxima, but only do on-the-fly plot if it was a recent "best" ////if (score > best) { maximaOut.printf("%.6g ", score); for (int i=0; i < x.length; i++) maximaOut.printf(" %.3f", x[i]); maximaOut.println(); maximaOut.flush(); if (score > best) { best = score; // plot here //if (oct != null) { double dPrev = reported.closest(x); if (dPrev > reportedThresh) { reported.add(x); // oct.send(String.format("%s([%.3f %.3f %.3f %.3f %.3f %.3f %.3f %.3f %.3f %.3f %.3f %.3f],%d)%n", // plotCmd,x[0],x[1],x[2],x[3],x[4],x[5],x[6],x[7],x[8],x[9],x[10],x[11],n)); //oct.printResp(System.err,"cmdOut"); // this does not wait til "done", but does keep us from getting more than 1 plot ahead plotConfig(metric._linkage,n++,metric._desc); } else nSkipped++; //} } // had some trouble with adjustable scale rate, abandoned this: //scale = 4+Math.log10(score); //if (scale < 1) scale=1; //scale /= Math.log10(best); if (scale > .95) scale=.95; if (scale < 0.001) scale = 0.001; best *= scale; // let this shrink to "reset" occationally // scoot towards seed so we don't get too crazy for (int i=0; i < x.length; i++) x[i] = gravity*seedState[i] + (1-gravity)*x[i]; // dump out orbit for diagnostics and plotting. /* PrintStream out; try {out = new PrintStream(new File("orbit.dat"));} catch(Exception e){out = System.out;} a._linkage.printOrbitFull(96, out); a._linkage.flip(); a._linkage.printOrbitFull(96, out); out.close(); */ } // end while(true) // if (maximaOut != System.out) // maximaOut.close(); } // end main() /// add some random noise (gaussian) to a vector public static double[] randomize(double[] xx, double changeProb, double stepSD) { if (rand == null) rand = new Random(System.currentTimeMillis()); double[] x = xx.clone(); for (int i=0; i < x.length; i++) { if (rand.nextDouble() < changeProb) { x[i] += stepSD*rand.nextGaussian(); } } return x; } public static void plotConfig(JansenLinkage jl, int n, String[] desc) { String fNam = String.format("JansenOpt%04d.svg", n); jl.plotOrbit(128,2,fNam,desc); } } // end OptJansen class