/**
* Write the current cell array to the given row of the image file.
*
* @param r Row index.
*/
private static void writeCurrentCell(int r) throws IOException {
// Set image row's gray values based on current cell states.
for (int i = 0; i < C; ++i) {
imagerow.setPixel(i, currentCell[i].floatValue());
}
// Set row r of the pixel matrix.
pixelmatrix[r] = pixelrow;
// Write row-r slice of the image to the image file.
writer.writeRowSlice(new Range(r, r));
}
/** Main program. */
public static void main(String[] args) throws Exception {
// Start timing.
long t1 = System.currentTimeMillis();
// Parse command line arguments.
if (args.length != 5) usage();
int argi = 0;
C = Integer.parseInt(args[0]);
S = Integer.parseInt(args[1]);
A = new BigRational(args[2]).mul(ONE_THIRD);
B = new BigRational(args[3]);
imagefile = new File(args[4]);
// Allocate storage for old and new cell arrays. Initialize all cells to
// 0, except center cell to 1.
currentCell = new BigRational[C];
nextCell = new BigRational[C];
for (int i = 0; i < C; ++i) {
currentCell[i] = new BigRational();
nextCell[i] = new BigRational();
}
currentCell[C / 2].assign(ONE);
// Set up pixel matrix, image, and image writer.
pixelmatrix = new byte[S + 1][];
image = new PJGGrayImage(S + 1, C, pixelmatrix);
writer = image.prepareToWrite(new BufferedOutputStream(new FileOutputStream(imagefile)));
// Allocate storage for one pixel matrix row.
pixelrow = new byte[C];
imagerow = new GrayImageRow(pixelrow);
imagerow.setInterpretation(PJGGrayImage.ZERO_IS_WHITE);
// Parallel calculation section.
new ParallelTeam()
.execute(
new ParallelRegion() {
public void run() throws Exception {
// Do S time steps. Sequential outer loop.
for (int s = 0; s < S; ++s) {
final int step = s;
// Calculate next state of each cell. Parallel inner loop.
execute(
0,
C - 1,
new IntegerForLoop() {
public IntegerSchedule schedule() {
return IntegerSchedule.guided();
}
public void run(int first, int last) {
for (int i = first; i <= last; ++i) {
nextCell[i]
.assign(currentCell[i])
.add(currentCell[(i - 1 + C) % C])
.add(currentCell[(i + 1) % C])
.mul(A)
.add(B)
.normalize()
.fracPart();
}
}
},
// Synchronize threads before next outer loop iteration.
new BarrierAction() {
public void run() throws Exception {
// Write current CA state to image file.
writeCurrentCell(step);
// Advance one time step -- swap old and new cell
// arrays.
BigRational[] tmp = currentCell;
currentCell = nextCell;
nextCell = tmp;
}
});
}
}
});
// Write final CA state to image file.
writeCurrentCell(S);
writer.close();
// Stop timing.
long t2 = System.currentTimeMillis();
System.out.println((t2 - t1) + " msec total");
}