/** Performs symbolic mix of fluids in given target ratios. */
Fluid mix(Fluid[] fluid, double[] target) {
assert fluid.length == target.length;
// prune out zero-weights
int numZeros = 0;
for (int i = 0; i < fluid.length; i++) {
if (target[i] == 0) {
numZeros++;
}
}
if (numZeros > 0) {
Fluid[] _fluid = new Fluid[fluid.length - numZeros];
double[] _target = new double[fluid.length - numZeros];
int pos = 0;
for (int i = 0; i < fluid.length; i++) {
if (target[i] != 0) {
_fluid[pos] = fluid[i];
_target[pos] = target[i];
pos++;
}
}
fluid = _fluid;
target = _target;
}
// if we're down to one fluid, return it
if (fluid.length == 1) {
return fluid[0];
}
// normalize the targets
double sum = 0;
for (int i = 0; i < target.length; i++) {
sum += target[i];
}
for (int i = 0; i < target.length; i++) {
target[i] /= sum;
}
// find depth of mixing tree that is needed to obtain
// precision
int depth = 0;
int[] ratios = null;
do {
depth++;
ratios = getRatios(depth, target);
} while (ratios == null);
assert depth < 32 : "Depth is " + depth + ", bigger than 32: bit-width issues.";
// System.out.println("ratio (" + ratios.length + "): " + ratios[0] + ":" + ratios[1] + ";
// depth=" + depth);
// break up ratios into bins
Stack[] bins = new Stack[depth + 1];
for (int i = 0; i < bins.length; i++) {
bins[i] = new Stack();
}
for (int i = 0; i < target.length; i++) {
int mask = 1;
for (int j = 0; j < depth; j++) {
if ((mask & ratios[i]) != 0) {
bins[j].push(fluid[i]);
}
mask = mask << 1;
}
}
BasicFluid result = buildMixingTree(bins, depth);
// this toggles a greedy evaluation instead of demand-driven
result.ensureAvail();
return result;
}
/** Dump dependency dot-graph to <filename>. */
public void dumpGraph(String filename) {
BasicFluid.dumpGraph(filename);
}