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comparison: js/src/v8/navier-stokes.js

js/src/v8/navier-stokes.js

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TOR_BUG_3246
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-1:000000000000 0:3a39cc4e6380
1 /**
2 * Copyright 2012 the V8 project authors. All rights reserved.
3 * Copyright 2009 Oliver Hunt <http://nerget.com>
4 *
5 * Permission is hereby granted, free of charge, to any person
6 * obtaining a copy of this software and associated documentation
7 * files (the "Software"), to deal in the Software without
8 * restriction, including without limitation the rights to use,
9 * copy, modify, merge, publish, distribute, sublicense, and/or sell
10 * copies of the Software, and to permit persons to whom the
11 * Software is furnished to do so, subject to the following
12 * conditions:
13 *
14 * The above copyright notice and this permission notice shall be
15 * included in all copies or substantial portions of the Software.
16 *
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
18 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
19 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
20 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
21 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
22 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
23 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
24 * OTHER DEALINGS IN THE SOFTWARE.
25 */
26
27 var NavierStokes = new BenchmarkSuite('NavierStokes', 1484000,
28 [new Benchmark('NavierStokes',
29 runNavierStokes,
30 setupNavierStokes,
31 tearDownNavierStokes)]);
32
33 var solver = null;
34
35 function runNavierStokes()
36 {
37 solver.update();
38 }
39
40 function setupNavierStokes()
41 {
42 solver = new FluidField(null);
43 solver.setResolution(128, 128);
44 solver.setIterations(20);
45 solver.setDisplayFunction(function(){});
46 solver.setUICallback(prepareFrame);
47 solver.reset();
48 }
49
50 function tearDownNavierStokes()
51 {
52 solver = null;
53 }
54
55 function addPoints(field) {
56 var n = 64;
57 for (var i = 1; i <= n; i++) {
58 field.setVelocity(i, i, n, n);
59 field.setDensity(i, i, 5);
60 field.setVelocity(i, n - i, -n, -n);
61 field.setDensity(i, n - i, 20);
62 field.setVelocity(128 - i, n + i, -n, -n);
63 field.setDensity(128 - i, n + i, 30);
64 }
65 }
66
67 var framesTillAddingPoints = 0;
68 var framesBetweenAddingPoints = 5;
69
70 function prepareFrame(field)
71 {
72 if (framesTillAddingPoints == 0) {
73 addPoints(field);
74 framesTillAddingPoints = framesBetweenAddingPoints;
75 framesBetweenAddingPoints++;
76 } else {
77 framesTillAddingPoints--;
78 }
79 }
80
81 // Code from Oliver Hunt (http://nerget.com/fluidSim/pressure.js) starts here.
82 function FluidField(canvas) {
83 function addFields(x, s, dt)
84 {
85 for (var i=0; i<size ; i++ ) x[i] += dt*s[i];
86 }
87
88 function set_bnd(b, x)
89 {
90 if (b===1) {
91 for (var i = 1; i <= width; i++) {
92 x[i] = x[i + rowSize];
93 x[i + (height+1) *rowSize] = x[i + height * rowSize];
94 }
95
96 for (var j = 1; i <= height; i++) {
97 x[j * rowSize] = -x[1 + j * rowSize];
98 x[(width + 1) + j * rowSize] = -x[width + j * rowSize];
99 }
100 } else if (b === 2) {
101 for (var i = 1; i <= width; i++) {
102 x[i] = -x[i + rowSize];
103 x[i + (height + 1) * rowSize] = -x[i + height * rowSize];
104 }
105
106 for (var j = 1; j <= height; j++) {
107 x[j * rowSize] = x[1 + j * rowSize];
108 x[(width + 1) + j * rowSize] = x[width + j * rowSize];
109 }
110 } else {
111 for (var i = 1; i <= width; i++) {
112 x[i] = x[i + rowSize];
113 x[i + (height + 1) * rowSize] = x[i + height * rowSize];
114 }
115
116 for (var j = 1; j <= height; j++) {
117 x[j * rowSize] = x[1 + j * rowSize];
118 x[(width + 1) + j * rowSize] = x[width + j * rowSize];
119 }
120 }
121 var maxEdge = (height + 1) * rowSize;
122 x[0] = 0.5 * (x[1] + x[rowSize]);
123 x[maxEdge] = 0.5 * (x[1 + maxEdge] + x[height * rowSize]);
124 x[(width+1)] = 0.5 * (x[width] + x[(width + 1) + rowSize]);
125 x[(width+1)+maxEdge] = 0.5 * (x[width + maxEdge] + x[(width + 1) + height * rowSize]);
126 }
127
128 function lin_solve(b, x, x0, a, c)
129 {
130 if (a === 0 && c === 1) {
131 for (var j=1 ; j<=height; j++) {
132 var currentRow = j * rowSize;
133 ++currentRow;
134 for (var i = 0; i < width; i++) {
135 x[currentRow] = x0[currentRow];
136 ++currentRow;
137 }
138 }
139 set_bnd(b, x);
140 } else {
141 var invC = 1 / c;
142 for (var k=0 ; k<iterations; k++) {
143 for (var j=1 ; j<=height; j++) {
144 var lastRow = (j - 1) * rowSize;
145 var currentRow = j * rowSize;
146 var nextRow = (j + 1) * rowSize;
147 var lastX = x[currentRow];
148 ++currentRow;
149 for (var i=1; i<=width; i++)
150 lastX = x[currentRow] = (x0[currentRow] + a*(lastX+x[++currentRow]+x[++lastRow]+x[++nextRow])) * invC;
151 }
152 set_bnd(b, x);
153 }
154 }
155 }
156
157 function diffuse(b, x, x0, dt)
158 {
159 var a = 0;
160 lin_solve(b, x, x0, a, 1 + 4*a);
161 }
162
163 function lin_solve2(x, x0, y, y0, a, c)
164 {
165 if (a === 0 && c === 1) {
166 for (var j=1 ; j <= height; j++) {
167 var currentRow = j * rowSize;
168 ++currentRow;
169 for (var i = 0; i < width; i++) {
170 x[currentRow] = x0[currentRow];
171 y[currentRow] = y0[currentRow];
172 ++currentRow;
173 }
174 }
175 set_bnd(1, x);
176 set_bnd(2, y);
177 } else {
178 var invC = 1/c;
179 for (var k=0 ; k<iterations; k++) {
180 for (var j=1 ; j <= height; j++) {
181 var lastRow = (j - 1) * rowSize;
182 var currentRow = j * rowSize;
183 var nextRow = (j + 1) * rowSize;
184 var lastX = x[currentRow];
185 var lastY = y[currentRow];
186 ++currentRow;
187 for (var i = 1; i <= width; i++) {
188 lastX = x[currentRow] = (x0[currentRow] + a * (lastX + x[currentRow] + x[lastRow] + x[nextRow])) * invC;
189 lastY = y[currentRow] = (y0[currentRow] + a * (lastY + y[++currentRow] + y[++lastRow] + y[++nextRow])) * invC;
190 }
191 }
192 set_bnd(1, x);
193 set_bnd(2, y);
194 }
195 }
196 }
197
198 function diffuse2(x, x0, y, y0, dt)
199 {
200 var a = 0;
201 lin_solve2(x, x0, y, y0, a, 1 + 4 * a);
202 }
203
204 function advect(b, d, d0, u, v, dt)
205 {
206 var Wdt0 = dt * width;
207 var Hdt0 = dt * height;
208 var Wp5 = width + 0.5;
209 var Hp5 = height + 0.5;
210 for (var j = 1; j<= height; j++) {
211 var pos = j * rowSize;
212 for (var i = 1; i <= width; i++) {
213 var x = i - Wdt0 * u[++pos];
214 var y = j - Hdt0 * v[pos];
215 if (x < 0.5)
216 x = 0.5;
217 else if (x > Wp5)
218 x = Wp5;
219 var i0 = x | 0;
220 var i1 = i0 + 1;
221 if (y < 0.5)
222 y = 0.5;
223 else if (y > Hp5)
224 y = Hp5;
225 var j0 = y | 0;
226 var j1 = j0 + 1;
227 var s1 = x - i0;
228 var s0 = 1 - s1;
229 var t1 = y - j0;
230 var t0 = 1 - t1;
231 var row1 = j0 * rowSize;
232 var row2 = j1 * rowSize;
233 d[pos] = s0 * (t0 * d0[i0 + row1] + t1 * d0[i0 + row2]) + s1 * (t0 * d0[i1 + row1] + t1 * d0[i1 + row2]);
234 }
235 }
236 set_bnd(b, d);
237 }
238
239 function project(u, v, p, div)
240 {
241 var h = -0.5 / Math.sqrt(width * height);
242 for (var j = 1 ; j <= height; j++ ) {
243 var row = j * rowSize;
244 var previousRow = (j - 1) * rowSize;
245 var prevValue = row - 1;
246 var currentRow = row;
247 var nextValue = row + 1;
248 var nextRow = (j + 1) * rowSize;
249 for (var i = 1; i <= width; i++ ) {
250 div[++currentRow] = h * (u[++nextValue] - u[++prevValue] + v[++nextRow] - v[++previousRow]);
251 p[currentRow] = 0;
252 }
253 }
254 set_bnd(0, div);
255 set_bnd(0, p);
256
257 lin_solve(0, p, div, 1, 4 );
258 var wScale = 0.5 * width;
259 var hScale = 0.5 * height;
260 for (var j = 1; j<= height; j++ ) {
261 var prevPos = j * rowSize - 1;
262 var currentPos = j * rowSize;
263 var nextPos = j * rowSize + 1;
264 var prevRow = (j - 1) * rowSize;
265 var currentRow = j * rowSize;
266 var nextRow = (j + 1) * rowSize;
267
268 for (var i = 1; i<= width; i++) {
269 u[++currentPos] -= wScale * (p[++nextPos] - p[++prevPos]);
270 v[currentPos] -= hScale * (p[++nextRow] - p[++prevRow]);
271 }
272 }
273 set_bnd(1, u);
274 set_bnd(2, v);
275 }
276
277 function dens_step(x, x0, u, v, dt)
278 {
279 addFields(x, x0, dt);
280 diffuse(0, x0, x, dt );
281 advect(0, x, x0, u, v, dt );
282 }
283
284 function vel_step(u, v, u0, v0, dt)
285 {
286 addFields(u, u0, dt );
287 addFields(v, v0, dt );
288 var temp = u0; u0 = u; u = temp;
289 var temp = v0; v0 = v; v = temp;
290 diffuse2(u,u0,v,v0, dt);
291 project(u, v, u0, v0);
292 var temp = u0; u0 = u; u = temp;
293 var temp = v0; v0 = v; v = temp;
294 advect(1, u, u0, u0, v0, dt);
295 advect(2, v, v0, u0, v0, dt);
296 project(u, v, u0, v0 );
297 }
298 var uiCallback = function(d,u,v) {};
299
300 function Field(dens, u, v) {
301 // Just exposing the fields here rather than using accessors is a measurable win during display (maybe 5%)
302 // but makes the code ugly.
303 this.setDensity = function(x, y, d) {
304 dens[(x + 1) + (y + 1) * rowSize] = d;
305 }
306 this.getDensity = function(x, y) {
307 return dens[(x + 1) + (y + 1) * rowSize];
308 }
309 this.setVelocity = function(x, y, xv, yv) {
310 u[(x + 1) + (y + 1) * rowSize] = xv;
311 v[(x + 1) + (y + 1) * rowSize] = yv;
312 }
313 this.getXVelocity = function(x, y) {
314 return u[(x + 1) + (y + 1) * rowSize];
315 }
316 this.getYVelocity = function(x, y) {
317 return v[(x + 1) + (y + 1) * rowSize];
318 }
319 this.width = function() { return width; }
320 this.height = function() { return height; }
321 }
322 function queryUI(d, u, v)
323 {
324 for (var i = 0; i < size; i++)
325 u[i] = v[i] = d[i] = 0.0;
326 uiCallback(new Field(d, u, v));
327 }
328
329 this.update = function () {
330 queryUI(dens_prev, u_prev, v_prev);
331 vel_step(u, v, u_prev, v_prev, dt);
332 dens_step(dens, dens_prev, u, v, dt);
333 displayFunc(new Field(dens, u, v));
334 }
335 this.setDisplayFunction = function(func) {
336 displayFunc = func;
337 }
338
339 this.iterations = function() { return iterations; }
340 this.setIterations = function(iters) {
341 if (iters > 0 && iters <= 100)
342 iterations = iters;
343 }
344 this.setUICallback = function(callback) {
345 uiCallback = callback;
346 }
347 var iterations = 10;
348 var visc = 0.5;
349 var dt = 0.1;
350 var dens;
351 var dens_prev;
352 var u;
353 var u_prev;
354 var v;
355 var v_prev;
356 var width;
357 var height;
358 var rowSize;
359 var size;
360 var displayFunc;
361 function reset()
362 {
363 rowSize = width + 2;
364 size = (width+2)*(height+2);
365 dens = new Array(size);
366 dens_prev = new Array(size);
367 u = new Array(size);
368 u_prev = new Array(size);
369 v = new Array(size);
370 v_prev = new Array(size);
371 for (var i = 0; i < size; i++)
372 dens_prev[i] = u_prev[i] = v_prev[i] = dens[i] = u[i] = v[i] = 0;
373 }
374 this.reset = reset;
375 this.setResolution = function (hRes, wRes)
376 {
377 var res = wRes * hRes;
378 if (res > 0 && res < 1000000 && (wRes != width || hRes != height)) {
379 width = wRes;
380 height = hRes;
381 reset();
382 return true;
383 }
384 return false;
385 }
386 this.setResolution(64, 64);
387 }

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