/** Main program. */
public static void main(String[] args) throws Exception {
// Parse command line arguments.
if (args.length != 3) usage();
C = Integer.parseInt(args[1]);
S = Integer.parseInt(args[0]) - 1;
A = ONE_THIRD;
B = new BigRational("9/10");
filename = new File(args[2]);
// Allocate storage for old and new cell arrays. Initialize all cells to
// 0, except center cell to 1.
currCell = new BigRational[C];
nextCell = new BigRational[C];
for (int i = 0; i < C; ++i) {
currCell[i] = new BigRational();
nextCell[i] = new BigRational();
}
currCell[C / 2].assign(ONE);
// Allocate storage for output image.
matrix = new byte[S + 1][C];
image = new PJGGrayImage(S + 1, C, matrix);
image.setInterpretation(PJGGrayImage.ZERO_IS_WHITE);
// Do S time steps.
for (int s = 0; s < S; ++s) {
// Calculate next state of each cell.
for (int i = 0; i < C; ++i) {
nextCell[i]
.assign(currCell[i])
.add(currCell[(i - 1 + C) % C])
.add(currCell[(i + 1) % C])
.mul(A)
.add(B)
.normalize()
.fracPart();
}
// Write current CA state to image matrix.
writeCurrCell(s);
// Advance one time step -- swap old and new cell arrays.
BigRational[] tmp = currCell;
currCell = nextCell;
nextCell = tmp;
}
// Write final CA state to image matrix.
writeCurrCell(S);
// Write output image to PJG file.
PJGImage.Writer writer =
image.prepareToWrite(new BufferedOutputStream(new FileOutputStream(filename)));
writer.write();
writer.close();
// Read image from file into a different matrix.
image2 = new PJGGrayImage();
PJGImage.Reader reader =
image2.prepareToRead(new BufferedInputStream(new FileInputStream(filename)));
reader.read();
reader.close();
// Compare output matrix with input matrix.
matrix2 = image2.getMatrix();
for (int r = 0; r <= S; ++r) {
byte[] matrix_r = matrix[r];
byte[] matrix2_r = matrix2[r];
for (int c = 0; c < C; ++c) {
if (matrix_r[c] != matrix2_r[c]) {
System.out.print("matrix[");
System.out.print(r);
System.out.print("][");
System.out.print(c);
System.out.print("] = ");
System.out.print(Hex.toString(matrix_r[c]));
System.out.print(", matrix2[");
System.out.print(r);
System.out.print("][");
System.out.print(c);
System.out.print("] = ");
System.out.print(Hex.toString(matrix2_r[c]));
System.out.println();
}
}
}
}
/**
* Write the current cell array to the image file.
*
* @param s Step (image row) index.
*/
private static void writeCurrCell(int s) throws IOException {
for (int i = 0; i < C; ++i) {
image.setPixel(s, i, currCell[i].floatValue());
}
}