michael@0: // Adapted from
michael@0: //
michael@0: // https://github.com/RiverTrail/RiverTrail/blob/master/examples/mandelbrot/mandelbrot.js
michael@0: //
michael@0: // which in turn is adapted from a WebCL implementation available at
michael@0: //
michael@0: // http://www.ibiblio.org/e-notes/webcl/mandelbrot.html
michael@0: 
michael@0: load(libdir + "parallelarray-helpers.js");
michael@0: 
michael@0: var nc = 30, maxCol = nc*3;
michael@0: 
michael@0: // this is the actual mandelbrot computation, ported to JavaScript
michael@0: // from the WebCL / OpenCL example at
michael@0: // http://www.ibiblio.org/e-notes/webcl/mandelbrot.html
michael@0: function computeSetByRow(x, y) {
michael@0:   var Cr = (x - 256) / scale + 0.407476;
michael@0:   var Ci = (y - 256) / scale + 0.234204;
michael@0:   var I = 0, R = 0, I2 = 0, R2 = 0;
michael@0:   var n = 0;
michael@0:   while ((R2+I2 < 2.0) && (n < 512)) {
michael@0:     I = (R+R)*I+Ci;
michael@0:     R = R2-I2+Cr;
michael@0:     R2 = R*R;
michael@0:     I2 = I*I;
michael@0:     n++;
michael@0:   }
michael@0:   return n;
michael@0: }
michael@0: 
michael@0: function computeSequentially() {
michael@0:   result = [];
michael@0:   for (var r = 0; r < rows; r++) {
michael@0:     for (var c = 0; c < cols; c++) {
michael@0:       result.push(computeSetByRow(r, c));
michael@0:     }
michael@0:   }
michael@0:   return result;
michael@0: }
michael@0: 
michael@0: var scale = 10000*300;
michael@0: var rows = 4;
michael@0: var cols = 4;
michael@0: 
michael@0: // check that we get correct result
michael@0: if (getBuildConfiguration().parallelJS) {
michael@0:   var expected = computeSequentially();
michael@0:   assertParallelExecSucceeds(
michael@0:     function (m) Array.buildPar(rows * cols, function (xy) {
michael@0:       return computeSetByRow((xy/cols)|0,(xy%cols))
michael@0:     }, m),
michael@0:     function (r) assertStructuralEq(expected, r));
michael@0: }