Add Navier-Stokes benchmark.

benchmarks/navier-stokes.js

+/**
+ * Copyright (c) 2012 the V8 project authors. All rights reserved.
+ * Copyright (c) 2009 Oliver Hunt <http://nerget.com>
+ * 
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following
+ * conditions:
+ * 
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+var name = 'navier-stokes2';

[kasperl, 2012/02/09 07:09:12]

I think you should make this fit with the other benchmarks in the V8 benchmark
suite before submitting it. I don't think you need the name variable.

You'll need to create a setup, run, and tear down function (you almost have
these). The tear down function should reset the global |solver| variable to
undefined or null so that a GC will get rid of the FluidField object.

Also it would be good to make sure to update the documentation (in the various
html and readme files).

+
+function setupNavierStokes()
+{   
+    solver = new FluidField(null);

[kasperl, 2012/02/09 07:09:12]

The |solver| variable is undeclared. Add a global solver variable with 'var'.
Another thing: Could we make this 2 space indent instead of 4?

+    solver.setResolution(128, 128);
+    solver.setIterations(20);
+    solver.setDisplayFunction(function(){});
+    solver.setUICallback(prepareFrame);
+    solver.reset();
+}
+
+function runNavierStokes()

[kasperl, 2012/02/09 07:09:12]

I would replace this entire method with a call to solver.update() and use the
benchmark harness from base.js to drive it.

+{
+    var elapsed = 0;
+    var start = new Date();
+    for (var n = 0; elapsed < 3000; n++) {
+        solver.update();
+        elapsed = new Date() - start;
+    }
+    var usec = 1000 * elapsed / n;
+    print('Time (' + name + '): ' + Math.round(usec) + ' us.');
+}
+
+// Add new source point.
+function addPoint(field, omx, omy, mx, my) {
+    var displaySize = 512;
+    // This code is copied from Oliver's html page.

[kasperl, 2012/02/09 07:09:12]

Reference to the exact page?

+    var dx = mx - omx;
+    var dy = my - omy;
+    var length = (Math.sqrt(dx * dx + dy * dy) + 0.5) | 0;
+    if (length < 1) length = 1;
+    for (var i = 0; i < length; i++) {
+        var x = (((omx + dx * (i / length)) / displaySize) * field.width()) | 0
+        var y = (((omy + dy * (i / length)) / displaySize) * field.height()) | 0;
+        field.setVelocity(x, y, dx, dy);
+        field.setDensity(x, y, 50);
+    }
+}
+
+// Random coordinates.
+var x1 = [329, 312, 62, 326, 96, 480, 359, 487, 

[kasperl, 2012/02/09 07:09:12]

If any of these variables change during the execution of the benchmark, it would
be nice to make sure they are initialized in the setup function.

+          40, 75, 249, 201, 145, 51, 227, 474, 10]; 
+var y1 = [46, 143, 457, 71, 488, 155, 91, 318, 495,
+          221, 232, 8, 483, 206, 423, 386];
+var x2 = [440, 303, 417, 213, 510, 512, 340, 338,
+          111, 406, 205, 447, 187, 305, 174];
+var y2 = [101, 114, 381, 299, 444, 110, 151, 228, 173, 146, 215];
+var framesTillAddingPoint = 0;
+var framesBetweenAddingPoints = 5;
+var pointCount = 0;

[kasperl, 2012/02/09 07:09:12]

Is there anyway you can check that the benchmark behaves correctly based on some
of these counters? In general, it is much better if the benchmarks do at least a
certain amount of checking (some of it might be postponable to the tear down
face).

+
+// Simulate user interaction.
+function prepareFrame(field)
+{
+    if (framesTillAddingPoint == 0) {
+        pointCount++;
+        addPoint(field, x1[pointCount % x1.length], y1[pointCount % y1.length],
+                 x2[pointCount % x2.length], y2[pointCount % y2.length]);
+        framesTillAddingPoint = framesBetweenAddingPoints;
+        framesBetweenAddingPoints++;
+    } else {
+        framesTillAddingPoint--;
+    }
+}
+
+setupNavierStokes();

[kasperl, 2012/02/09 07:09:12]

These two calls should be dealt with by the benchmark harness.

+runNavierStokes();
+
+// Original code from Oliver Hunt starts here.
+function FluidField(canvas) {
+    function addFields(x, s, dt)
+    {
+        for (var i=0; i<size ; i++ ) x[i] += dt*s[i];
+    }
+
+    function set_bnd(b, x)
+    {
+        if (b===1) {
+            for (var i = 1; i <= width; i++) {
+                x[i] =  x[i + rowSize];
+                x[i + (height+1) *rowSize] = x[i + height * rowSize];
+            }
+
+            for (var j = 1; i <= height; i++) {
+                x[j * rowSize] = -x[1 + j * rowSize];
+                x[(width + 1) + j * rowSize] = -x[width + j * rowSize];
+            }
+        } else if (b === 2) {
+            for (var i = 1; i <= width; i++) {
+                x[i] = -x[i + rowSize];
+                x[i + (height + 1) * rowSize] = -x[i + height * rowSize];
+            }
+
+            for (var j = 1; j <= height; j++) {
+                x[j * rowSize] =  x[1 + j * rowSize];
+                x[(width + 1) + j * rowSize] =  x[width + j * rowSize];
+            }
+        } else {
+            for (var i = 1; i <= width; i++) {
+                x[i] =  x[i + rowSize];
+                x[i + (height + 1) * rowSize] = x[i + height * rowSize];
+            }
+
+            for (var j = 1; j <= height; j++) {
+                x[j * rowSize] =  x[1 + j * rowSize];
+                x[(width + 1) + j * rowSize] =  x[width + j * rowSize];
+            }
+        }
+        var maxEdge = (height + 1) * rowSize;
+        x[0]                 = 0.5 * (x[1] + x[rowSize]);
+        x[maxEdge]           = 0.5 * (x[1 + maxEdge] + x[height * rowSize]);
+        x[(width+1)]         = 0.5 * (x[width] + x[(width + 1) + rowSize]);
+        x[(width+1)+maxEdge] = 0.5 * (x[width + maxEdge] + x[(width + 1) + height * rowSize]);
+    }
+
+    function lin_solve(b, x, x0, a, c)
+    {
+        if (a === 0 && c === 1) {
+            for (var j=1 ; j<=height; j++) {
+                var currentRow = j * rowSize;
+                ++currentRow;
+                for (var i = 0; i < width; i++) {
+                    x[currentRow] = x0[currentRow];
+                    ++currentRow;
+                }
+            }
+            set_bnd(b, x);
+        } else {
+            var invC = 1 / c;
+            for (var k=0 ; k<iterations; k++) {
+                for (var j=1 ; j<=height; j++) {
+                    var lastRow = (j - 1) * rowSize;
+                    var currentRow = j * rowSize;
+                    var nextRow = (j + 1) * rowSize;
+                    var lastX = x[currentRow];
+                    ++currentRow;
+                    for (var i=1; i<=width; i++)
+                        lastX = x[currentRow] = (x0[currentRow] + a*(lastX+x[++currentRow]+x[++lastRow]+x[++nextRow])) * invC;
+                }
+                set_bnd(b, x);
+            }
+        }
+    }
+    
+    function diffuse(b, x, x0, dt)
+    {
+        var a = 0;
+        lin_solve(b, x, x0, a, 1 + 4*a);
+    }
+    
+    function lin_solve2(x, x0, y, y0, a, c)
+    {
+        if (a === 0 && c === 1) {
+            for (var j=1 ; j <= height; j++) {
+                var currentRow = j * rowSize;
+                ++currentRow;
+                for (var i = 0; i < width; i++) {
+                    x[currentRow] = x0[currentRow];
+                    y[currentRow] = y0[currentRow];
+                    ++currentRow;
+                }
+            }
+            set_bnd(1, x);
+            set_bnd(2, y);
+        } else {
+            var invC = 1/c;
+            for (var k=0 ; k<iterations; k++) {
+                for (var j=1 ; j <= height; j++) {
+                    var lastRow = (j - 1) * rowSize;
+                    var currentRow = j * rowSize;
+                    var nextRow = (j + 1) * rowSize;
+                    var lastX = x[currentRow];
+                    var lastY = y[currentRow];
+                    ++currentRow;
+                    for (var i = 1; i <= width; i++) {
+                        lastX = x[currentRow] = (x0[currentRow] + a * (lastX + x[currentRow] + x[lastRow] + x[nextRow])) * invC;
+                        lastY = y[currentRow] = (y0[currentRow] + a * (lastY + y[++currentRow] + y[++lastRow] + y[++nextRow])) * invC;
+                    }
+                }
+                set_bnd(1, x);
+                set_bnd(2, y);
+            }
+        }
+    }
+    
+    function diffuse2(x, x0, y, y0, dt)
+    {
+        var a = 0;
+        lin_solve2(x, x0, y, y0, a, 1 + 4 * a);
+    }
+    
+    function advect(b, d, d0, u, v, dt)
+    {
+        var Wdt0 = dt * width;
+        var Hdt0 = dt * height;
+        var Wp5 = width + 0.5;
+        var Hp5 = height + 0.5;
+        for (var j = 1; j<= height; j++) {
+            var pos = j * rowSize;
+            for (var i = 1; i <= width; i++) {
+                var x = i - Wdt0 * u[++pos]; 
+                var y = j - Hdt0 * v[pos];
+                if (x < 0.5)
+                    x = 0.5;
+                else if (x > Wp5)
+                    x = Wp5;
+                var i0 = x | 0;
+                var i1 = i0 + 1;
+                if (y < 0.5)
+                    y = 0.5;
+                else if (y > Hp5)
+                    y = Hp5;
+                var j0 = y | 0;
+                var j1 = j0 + 1;
+                var s1 = x - i0;
+                var s0 = 1 - s1;
+                var t1 = y - j0;
+                var t0 = 1 - t1;
+                var row1 = j0 * rowSize;
+                var row2 = j1 * rowSize;
+                d[pos] = s0 * (t0 * d0[i0 + row1] + t1 * d0[i0 + row2]) + s1 * (t0 * d0[i1 + row1] + t1 * d0[i1 + row2]);
+            }
+        }
+        set_bnd(b, d);
+    }
+    
+    function project(u, v, p, div)
+    {
+        var h = -0.5 / Math.sqrt(width * height);
+        for (var j = 1 ; j <= height; j++ ) {
+            var row = j * rowSize;
+            var previousRow = (j - 1) * rowSize;
+            var prevValue = row - 1;
+            var currentRow = row;
+            var nextValue = row + 1;
+            var nextRow = (j + 1) * rowSize;
+            for (var i = 1; i <= width; i++ ) {
+                div[++currentRow] = h * (u[++nextValue] - u[++prevValue] + v[++nextRow] - v[++previousRow]);
+                p[currentRow] = 0;
+            }
+        }
+        set_bnd(0, div);
+        set_bnd(0, p);
+        
+        lin_solve(0, p, div, 1, 4 );
+        var wScale = 0.5 * width;
+        var hScale = 0.5 * height;
+        for (var j = 1; j<= height; j++ ) {
+            var prevPos = j * rowSize - 1;
+            var currentPos = j * rowSize;
+            var nextPos = j * rowSize + 1;
+            var prevRow = (j - 1) * rowSize;
+            var currentRow = j * rowSize;
+            var nextRow = (j + 1) * rowSize;
+
+            for (var i = 1; i<= width; i++) {
+                u[++currentPos] -= wScale * (p[++nextPos] - p[++prevPos]);
+                v[currentPos]   -= hScale * (p[++nextRow] - p[++prevRow]);
+            }
+        }
+        set_bnd(1, u);
+        set_bnd(2, v);
+    }
+    
+    function dens_step(x, x0, u, v, dt)
+    {
+        addFields(x, x0, dt);
+        diffuse(0, x0, x, dt );
+        advect(0, x, x0, u, v, dt );
+    }
+    
+    function vel_step(u, v, u0, v0, dt)
+    {
+        addFields(u, u0, dt );
+        addFields(v, v0, dt );
+        var temp = u0; u0 = u; u = temp;
+        var temp = v0; v0 = v; v = temp;
+        diffuse2(u,u0,v,v0, dt);
+        project(u, v, u0, v0);
+        var temp = u0; u0 = u; u = temp; 
+        var temp = v0; v0 = v; v = temp;
+        advect(1, u, u0, u0, v0, dt);
+        advect(2, v, v0, u0, v0, dt);
+        project(u, v, u0, v0 );
+    }
+    var uiCallback = function(d,u,v) {};
+
+    function Field(dens, u, v) {
+        // Just exposing the fields here rather than using accessors is a measurable win during display (maybe 5%)
+        // but makes the code ugly.
+        this.setDensity = function(x, y, d) {
+             dens[(x + 1) + (y + 1) * rowSize] = d;
+        }
+        this.getDensity = function(x, y) {
+             return dens[(x + 1) + (y + 1) * rowSize];
+        }
+        this.setVelocity = function(x, y, xv, yv) {
+             u[(x + 1) + (y + 1) * rowSize] = xv;
+             v[(x + 1) + (y + 1) * rowSize] = yv;
+        }
+        this.getXVelocity = function(x, y) {
+             return u[(x + 1) + (y + 1) * rowSize];
+        }
+        this.getYVelocity = function(x, y) {
+             return v[(x + 1) + (y + 1) * rowSize];
+        }
+        this.width = function() { return width; }
+        this.height = function() { return height; }
+    }
+    function queryUI(d, u, v)
+    {
+        for (var i = 0; i < size; i++)
+            u[i] = v[i] = d[i] = 0.0;
+        uiCallback(new Field(d, u, v));
+    }
+
+    this.update = function () {
+        queryUI(dens_prev, u_prev, v_prev);
+        vel_step(u, v, u_prev, v_prev, dt);
+        dens_step(dens, dens_prev, u, v, dt);
+        displayFunc(new Field(dens, u, v));
+    }
+    this.setDisplayFunction = function(func) {
+        displayFunc = func;
+    }
+    
+    this.iterations = function() { return iterations; }
+    this.setIterations = function(iters) {
+        if (iters > 0 && iters <= 100)
+           iterations = iters;
+    }
+    this.setUICallback = function(callback) {
+        uiCallback = callback;
+    }
+    var iterations = 10;
+    var visc = 0.5;
+    var dt = 0.1;
+    var dens;
+    var dens_prev;
+    var u;
+    var u_prev;
+    var v;
+    var v_prev;
+    var width;
+    var height;
+    var rowSize;
+    var size;
+    var displayFunc;
+    function reset()
+    {
+        rowSize = width + 2;
+        size = (width+2)*(height+2);
+        dens = new Array(size);
+        dens_prev = new Array(size);
+        u = new Array(size);
+        u_prev = new Array(size);
+        v = new Array(size);
+        v_prev = new Array(size);
+        for (var i = 0; i < size; i++)
+            dens_prev[i] = u_prev[i] = v_prev[i] = dens[i] = u[i] = v[i] = 0;
+    }
+    this.reset = reset;
+    this.setResolution = function (hRes, wRes)
+    {
+        var res = wRes * hRes;
+        if (res > 0 && res < 1000000 && (wRes != width || hRes != height)) {
+            width = wRes;
+            height = hRes;
+            reset();
+            return true;
+        }
+        return false;
+    }
+    this.setResolution(64, 64);
+}