!include #1000522 // image helper functions

static abstract class Predictor {
  // col = immutable array!
  abstract float[] nextColumn(float[] col);
}

sclass Best {
  S desc;
  double score;
  Predictor renderer;

  *() {}
  *(S *desc, double *score, Predictor *renderer) {}
  
  int l() { ret main.l(desc); }
}

sclass Reproducing {
  BWImage bw; // original
  float[][] bwCols; // in columns
  bool testFirst; // test first column?
  new LinkedBlockingQueue<S> newProducts;
  int maxQueueLength = 10;
  volatile Best shortest100, best;
  int pivotLength = -1; // no length punishment at start
  int pivotStep = 1;
  O startProduction; // optional runnable that starts production

  void push(S product) {
    if (product == null) ret;
    while (newProducts.size() >= maxQueueLength && mayRun())
      sleep(100);
    newProducts.add(product);
  }
  
  bool solved() {
    ret getScore(best) >= 100.0;
  }
  
  S bestDesc() {
    ret getDesc(best);
  }
  
  void produce() {
    callF(startProduction);
  }
  
  void search() {
    produce();
    
    long lastPrint = 0, lastN = 0;
    for (long ntry = 1; ; ntry++) {
      ping();
      long now = now();
      if (now >= lastPrint+1000) {
        long tps = (ntry-lastN)*1000/(now-lastPrint);
        lastPrint = now;
        lastN = ntry;
        String s = "Try " + ntry + " (" + tps + "/s)";
        /*if (best == null)
          print(s);
        else {
          print("Best: " + best.desc);
          print(s + ", score: " + formatDouble(best.score, 2) + "%, l=" + l(best.desc) + ", pivotL=" + pivotLength + "/" + fullGrabLength + (shortest100 == null ? "" : ", shortest100=" + shortest100.l()));
        }*/
      }
      S desc = grabFromQueue(newProducts);
      Predictor p;
      try {
        p = makePredictor(desc);
      } catch {
        print("Can't unstructure: " + desc);
        continue;
      }
      
      print("Predictor: " + desc);
      double score = testPredictor(p);
      print("  Score: " + score);
    }
  }
  
  Predictor nextPredictor() {
    S desc = grabFromQueue(newProducts);
    try {
      ret makePredictor(desc);
    } catch {
      print("Can't unstructure: " + desc);
      null;
    }
  }
  
  double testPredictor(Predictor p) {
    ret main.testPredictor(p, getCols(), testFirst);
  }
  
  float[][] getCols() {
    if (bwCols == null) bwCols = imageToColumns(bw);
    ret bwCols;
  }
}

static Predictor makePredictor(S desc) {
  ret (Predictor) unstructure(desc);
}

static double getScore(Best b) {
  ret b == null ? 0 : b.score;
}

static S getDesc(Best b) {
  ret b == null ? null : b.desc;
}

static float[][] imageToColumns(BWImage img) {
  int w = img.getWidth(), h = img.getHeight();
  float[][] f = new float[w][h];
  for x to w: for y to h: f[x][y] = img.getPixel(x, y);
  ret f;
}

static BWImage columnsToImage(float[][] cols) {
  ret columnsToImage(cols, l(cols[0]));
}
  
static BWImage columnsToImage(float[][] cols, int h) {
  float emptyBrightness = 0.5f;
  int w = l(cols);
  BWImage img = new BWImage(w, h, emptyBrightness);
  for x to w: if (cols[x] != null) for y to h:
    img.setPixel(x, y, cols[x][y]);
  ret img;
}

static float[] copyColumn(float[] f) {
  ret copyFloatArray(f);
}

static double testPredictor(Predictor p, float[][] bwCols, bool testFirst) {
  int w = l(bwCols), h = l(bwCols[0]);
  double error = 0;
  for (int x = testFirst ? 0 : 1; x < w; x++) {
    float[] f = p.nextColumn(x == 0 ? null : bwCols[x-1]);
    error += colDiff(f, bwCols[x]);
  }
  ret 1-error/((testFirst ? w : w-1)*h);
}

// x0 = from where we start feeding
// x1 = where we start testing
static double testColumnRange(Predictor p, float[][] bwCols, int x0, int x1, int x2) {
  int h = l(bwCols[0]);
  double error = 0;
  for (int x = x0; x < x2; x++) {
    float[] f = p.nextColumn(x == 0 ? null : bwCols[x-1]);
    if (x >= x1)
      error += colDiff(f, bwCols[x]);
  }
  ret 1-error/((x2-x1)*h);
}

static double colDiff(float[] a, float[] b) {
  if (a == null) ret l(b);
  if (b == null) ret l(a);
  int n = l(a);
  double d = 0;
  for (int i = 0; i < n; i++)
    d += Math.abs(a[i]-b[i]);
  ret d;
}

static BufferedImage renderPrediction(S desc, float[][] bwCols) {
  Predictor p = makePredictor(desc);
  int w = l(bwCols), h = l(bwCols[0]);
  float[][] cols = new float[w][];
  for (int x = 0; x < w; x++) {
    float[] f = p.nextColumn(x == 0 ? null : bwCols[x-1]);
    cols[x] = f;
  }
  ret columnsToImage(cols, h).getBufferedImage();
}

Began life as a copy of #1004556