The Tor Browser: js/src/parjs-benchmarks/nbody-seeded.js@b8a032363ba2 (annotated)

js/src/parjs-benchmarks/nbody-seeded.js@b8a032363ba2 (annotated)

js/src/parjs-benchmarks/nbody-seeded.js

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 //
 // NBody adapted from Intel's nbody benchmark.
 //
 load(libdir + "util.js");
 load(libdir + "seedrandom.js");
 var NBody = {
   Constant: {
     "deltaTime": 1,     // 0.005 in their code.
     "epsSqr": 50,       // softening factor, when they compute, set to 50.
     "initialVelocity": 8 // set to 0 to turn off
   },
   init: function init(mode, numBodies) {
     var initPos = new Array(numBodies);
     var initVel = new Array(numBodies);
     // initialization of inputs
     for (var i = 0; i < numBodies; i++) {
       // [x,y,z]
       initPos[i] = [Math.floor((Math.random()) * 40000),
                     Math.floor((Math.random()) * 20000),
                     Math.floor((Math.random() - .25) * 50000)];
       // [x,y,z,x,y,z]
       initVel[i] = [(Math.random() - 0.5) * NBody.Constant.initialVelocity,
                     (Math.random() - 0.5) * NBody.Constant.initialVelocity,
                     (Math.random()) * NBody.Constant.initialVelocity + 10,
                     (Math.random() - 0.5) * NBody.Constant.initialVelocity,
                     (Math.random() - 0.5) * NBody.Constant.initialVelocity,
                     (Math.random()) * NBody.Constant.initialVelocity];
     }
     NBody.private = {};
     if (mode === "par") {
       NBody.private.pos = new ParallelArray(initPos);
       NBody.private.vel = new ParallelArray(initVel);
     } else {
       NBody.private.pos = initPos;
       NBody.private.vel = initVel;
     }
     NBody.numBodies = numBodies;
     NBody.time = 0;
   },
   // Parallel
   tickPar: function tickPar() {
     NBody.private.vel = new ParallelArray([NBody.numBodies], NBody.velocityPar);
     NBody.private.pos = new ParallelArray([NBody.numBodies], NBody.positionPar);
     NBody.time++;
   },
   velocityPar: function velocityPar(index) {
     var pos = NBody.private.pos;
     var vel = NBody.private.vel;
     var deltaTime = NBody.Constant.deltaTime;
     var epsSqr = NBody.Constant.epsSqr;
     var time = NBody.time;
     var shape = vel.shape[0];
     var newVel;
     var newX, newY, newZ;
     var newX2, newY2, newZ2;
     var cX = Math.cos(time / 22) * -4200;
     var cY = Math.sin(time / 14) * 9200;
     var cZ = Math.sin(time / 27) * 6000;
     // pull to center
     var maxDistance = 3400;
     var pullStrength = .042;
     var speedLimit = 8;
     // zones
     var zone = 400;
     var repel = 100;
     var align = 300;
     var attract = 100;
     if (time < 500) {
       speedLimit = 2000;
       var attractPower = 100.9;
     } else {
       speedLimit = .2;
       attractPower = 20.9;
     }
     var zoneSqrd = zone * zone + zone * zone + zone * zone;
     var accX = 0, accY = 0, accZ = 0;
     var accX2 = 0, accY2 = 0, accZ2 = 0;
     var i;
     // define particle 1 center distance
     var dirToCenterX = cX - pos.get(index)[0];
     var dirToCenterY = cY - pos.get(index)[1];
     var dirToCenterZ = cZ - pos.get(index)[2];
     var distanceSquaredTo = dirToCenterX * dirToCenterX + dirToCenterY * dirToCenterY + dirToCenterZ * dirToCenterZ;
     var distToCenter = Math.sqrt(distanceSquaredTo);
     // orient to center
     if (distToCenter > maxDistance) {
       var velc = (distToCenter - maxDistance) * pullStrength;
       if (time < 200)
         velc = .2;
       else velc = (distToCenter - maxDistance) * pullStrength;
       accX += (dirToCenterX / distToCenter) * velc;
       accY += (dirToCenterY / distToCenter) * velc;
       accZ += (dirToCenterZ / distToCenter) * velc;
     }
     for (i = 0; i < shape; i = i + 1) {
       var rx = pos.get(i)[0] - pos.get(index)[0];
       var ry = pos.get(i)[1] - pos.get(index)[1];
       var rz = pos.get(i)[2] - pos.get(index)[2];
       // make sure we are not testing the particle against its own position
       var areSame = 0;
       if (pos.get(i)[0] == pos.get(index)[0] && pos.get(i)[1] == pos.get(index)[1] && pos.get(i)[2] == pos.get(index)[2])
         areSame += 1;
       var distSqrd = rx * rx + ry * ry + rz * rz;
       // cant use eqals to test, only <= or >= WTF
       if (distSqrd < zoneSqrd && areSame <= 0) {
         var length = Math.sqrt(distSqrd);
         var percent = distSqrd / zoneSqrd;
         if (distSqrd < repel) {
           var F = (repel / percent - 1) * .025;
           var normalRx = (rx / length) * F;
           var normalRy = (ry / length) * F;
           var normalRz = (rz / length) * F;
           accX = accX + normalRx;
           accY = accY + normalRy;
           accZ = accZ + normalRz;
           accX2 = accX2 - normalRx;
           accY2 = accY2 - normalRy;
           accZ2 = accZ2 - normalRz;
         } else if (distSqrd < align) { //align
           var threshDelta = align - repel;
           var adjustedPercent = (percent - repel) / threshDelta;
           var Q = (.5 - Math.cos(adjustedPercent * 3.14159265 * 2) * .5 + .5) * 100.9;
           // get velocity 2
           var velX2 = vel.get(i)[4];
           var velY2 = vel.get(i)[5];
           var velZ2 = vel.get(i)[6];
           var velLength2 = Math.sqrt(velX2 * velX2 + velY2 * velY2 + velZ2 * velZ2);
           // normalize vel2 and multiply by factor
           velX2 = (velX2 / velLength2) * Q;
           velY2 = (velY2 / velLength2) * Q;
           velZ2 = (velZ2 / velLength2) * Q;
           // get own velocity
           var velX = vel.get(i)[0];
           var velY = vel.get(i)[1];
           var velZ = vel.get(i)[2];
           var velLength = Math.sqrt(velX * velX + velY * velY + velZ * velZ);
           // normalize own velocity
           velX = (velX / velLength) * Q;
           velY = (velY / velLength) * Q;
           velZ = (velZ / velLength) * Q;
           accX += velX2;
           accY += velY2;
           accZ += velZ2;
           accX2 += velX;
           accY2 += velY;
           accZ2 += velZ;
         }
         if (distSqrd > attract) { // attract
           var threshDelta2 = 1 - attract;
           var adjustedPercent2 = (percent - attract) / threshDelta2;
           var C = (1 - (Math.cos(adjustedPercent2 * 3.14159265 * 2) * 0.5 + 0.5)) * attractPower;
           // normalize the distance vector
           var dx = (rx / (length)) * C;
           var dy = (ry / (length)) * C;
           var dz = (rz / (length)) * C;
           accX += dx;
           accY += dy;
           accZ += dz;
           accX2 -= dx;
           accY2 -= dy;
           accZ2 -= dz;
         }
       }
     }
     // Speed limits
     if (time > 500) {
       var accSquared = accX * accX + accY * accY + accZ * accZ;
       if (accSquared > speedLimit) {
         accX = accX * .015;
         accY = accY * .015;
         accZ = accZ * .015;
       }
       var accSquared2 = accX2 * accX2 + accY2 * accY2 + accZ2 * accZ2;
       if (accSquared2 > speedLimit) {
         accX2 = accX2 * .015;
         accY2 = accY2 * .015;
         accZ2 = accZ2 * .015;
       }
     }
     // Caclulate new velocity
     newX = (vel.get(index)[0]) + accX;
     newY = (vel.get(index)[1]) + accY;
     newZ = (vel.get(index)[2]) + accZ;
     newX2 = (vel.get(index)[3]) + accX2;
     newY2 = (vel.get(index)[4]) + accY2;
     newZ2 = (vel.get(index)[5]) + accZ2;
     if (time < 500) {
       var acs = newX2 * newX2 + newY2 * newY2 + newZ2 * newZ2;
       if (acs > speedLimit) {
         newX2 = newX2 * .15;
         newY2 = newY2 * .15;
         newZ2 = newZ2 * .15;
       }
       var acs2 = newX * newX + newY * newY + newZ * newZ;
       if (acs2 > speedLimit) {
         newX = newX * .15;
         newY = newY * .15;
         newZ = newZ * .15;
       }
     }
     return [newX, newY, newZ, newX2, newY2, newZ2];
   },
   positionPar: function positionPar(index) {
     var vel = NBody.private.vel;
     var pos = NBody.private.pos;
     var x = 0;
     var y = 0;
     var z = 0;
     var velX = vel.get(index)[0];
     var velY = vel.get(index)[1];
     var velZ = vel.get(index)[2];
     var velX2 = vel.get(index)[3];
     var velY2 = vel.get(index)[4];
     var velZ2 = vel.get(index)[5];
     var netVelX = (velX - velX2);
     var netVelY = (velY - velY2);
     var netVelZ = (velZ - velZ2);
     x = pos.get(index)[0] + (netVelX);
     y = pos.get(index)[1] + (netVelY);
     z = pos.get(index)[2] + (netVelZ);
     return [x, y, z];
   },
   // Sequential
   tickSeq: function tickSeq() {
     var numBodies = NBody.numBodies;
     var newVel = new Array(numBodies);
     var newPos = new Array(numBodies);
     for (var i = 0; i < numBodies; i++)
       newVel[i] = NBody.velocitySeq(i);
     for (var i = 0; i < numBodies; i++)
       newPos[i] = NBody.positionSeq(i);
     NBody.private.vel = newVel;
     NBody.private.pos = newPos;
     NBody.time++;
   },
   velocitySeq: function velocitySeq(index) {
     var vel = NBody.private.vel;
     var pos = NBody.private.pos;
     var deltaTime = NBody.Constant.deltaTime;
     var epsSqr = NBody.Constant.epsSqr;
     var time = NBody.time;
     var shape = pos.length;
     var newVel;
     var newX, newY, newZ;
     var newX2, newY2, newZ2;
     var cX = Math.cos(time / 22) * -4200;
     var cY = Math.sin(time / 14) * 9200;
     var cZ = Math.sin(time / 27) * 6000;
     // pull to center
     var maxDistance = 3400;
     var pullStrength = .042;
     var speedLimit = 8;
     // zones
     var zone = 400;
     var repel = 100;
     var align = 300;
     var attract = 100;
     if (time < 500) {
       speedLimit = 2000;
       var attractPower = 100.9;
     } else {
       speedLimit = .2;
       attractPower = 20.9;
     }
     var zoneSqrd = zone * zone + zone * zone + zone * zone;
     var accX = 0, accY = 0, accZ = 0;
     var accX2 = 0, accY2 = 0, accZ2 = 0;
     var i;
     // define particle 1 center distance
     var dirToCenterX = cX - pos[index][0];
     var dirToCenterY = cY - pos[index][1];
     var dirToCenterZ = cZ - pos[index][2];
     var distanceSquaredTo = dirToCenterX * dirToCenterX + dirToCenterY * dirToCenterY + dirToCenterZ * dirToCenterZ;
     var distToCenter = Math.sqrt(distanceSquaredTo);
     // orient to center
     if (distToCenter > maxDistance) {
       var velc = (distToCenter - maxDistance) * pullStrength;
       if (time < 200)
         velc = .2;
       else velc = (distToCenter - maxDistance) * pullStrength;
       accX += (dirToCenterX / distToCenter) * velc;
       accY += (dirToCenterY / distToCenter) * velc;
       accZ += (dirToCenterZ / distToCenter) * velc;
     }
     for (i = 0; i < shape; i = i + 1) {
       var rx = pos[i][0] - pos[index][0];
       var ry = pos[i][1] - pos[index][1];
       var rz = pos[i][2] - pos[index][2];
       var areSame = 0;
       if (pos[i][0] == pos[index][0] && pos[i][1] == pos[index][1] && pos[i][2] == pos[index][2])
         areSame += 1;
       var distSqrd = rx * rx + ry * ry + rz * rz;
       // cant use eqals to test, only <= or >= WTF
       if (distSqrd < zoneSqrd && areSame <= 0) {
         var length = Math.sqrt(distSqrd);
         var percent = distSqrd / zoneSqrd;
         if (distSqrd < repel) {
           var F = (repel / percent - 1) * .025;
           var normalRx = (rx / length) * F;
           var normalRy = (ry / length) * F;
           var normalRz = (rz / length) * F;
           accX = accX + normalRx;
           accY = accY + normalRy;
           accZ = accZ + normalRz;
           accX2 = accX2 - normalRx;
           accY2 = accY2 - normalRy;
           accZ2 = accZ2 - normalRz;
         } else if (distSqrd < align) { //align
           var threshDelta = align - repel;
           var adjustedPercent = (percent - repel) / threshDelta;
           var Q = (.5 - Math.cos(adjustedPercent * 3.14159265 * 2) * .5 + .5) * 100;
           // get velocity 2
           var velX2 = vel[i][3];
           var velY2 = vel[i][4];
           var velZ2 = vel[i][5];
           var velLength2 = Math.sqrt(velX2 * velX2 + velY2 * velY2 + velZ2 * velZ2);
           // normalize vel2 and multiply by factor
           velX2 = (velX2 / velLength2) * Q;
           velY2 = (velY2 / velLength2) * Q;
           velZ2 = (velZ2 / velLength2) * Q;
           // get own velocity
           var velX = vel[i][0];
           var velY = vel[i][1];
           var velZ = vel[i][2];
           var velLength = Math.sqrt(velX * velX + velY * velY + velZ * velZ);
           // normalize own velocity
           velX = (velX / velLength) * Q;
           velY = (velY / velLength) * Q;
           velZ = (velZ / velLength) * Q;
           accX += velX2;
           accY += velY2;
           accZ += velZ2;
           accX2 += velX;
           accY2 += velY;
           accZ2 += velZ;
         }
         if (distSqrd > attract) {        //attract
           var threshDelta2 = 1 - align;
           var adjustedPercent2 = (percent - align) / threshDelta2;
           var C = (1 - (Math.cos(adjustedPercent2 * 3.14159265 * 2) * 0.5 + 0.5)) * attractPower;
           // normalize the distance vector
           var dx = (rx / (length)) * C;
           var dy = (ry / (length)) * C;
           var dz = (rz / (length)) * C;
           debug = 1.1;
           accX += dx;
           accY += dy;
           accZ += dz;
           accX2 -= dx;
           accY2 -= dy;
           accZ2 -= dz;
         }
       }
     }
     // enforce speed limits
     if (time > 500) {
       var accSquared = accX * accX + accY * accY + accZ * accZ;
       if (accSquared > speedLimit) {
         accX = accX * .015;
         accY = accY * .015;
         accZ = accZ * .015;
       }
       var accSquared2 = accX2 * accX2 + accY2 * accY2 + accZ2 * accZ2;
       if (accSquared2 > speedLimit) {
         accX2 = accX2 * .015;
         accY2 = accY2 * .015;
         accZ2 = accZ2 * .015;
       }
     }
     // Caclulate new velocity
     newX = vel[index][0] + accX;
     newY = vel[index][1] + accY;
     newZ = vel[index][2] + accZ;
     newX2 = vel[index][3] + accX2;
     newY2 = vel[index][4] + accY2;
     newZ2 = vel[index][5] + accZ2;
     if (time < 500) {
       var acs = newX2 * newX2 + newY2 * newY2 + newZ2 * newZ2;
       if (acs > speedLimit) {
         newX2 = newX2 * .15;
         newY2 = newY2 * .15;
         newZ2 = newZ2 * .15;
       }
       var acs2 = newX * newX + newY * newY + newZ * newZ;
       if (acs2 > speedLimit) {
         newX = newX * .15;
         newY = newY * .15;
         newZ = newZ * .15;
       }
     }
     return [newX, newY, newZ, newX2, newY2, newZ2];
   },
   positionSeq: function positionSeq(index) {
     var vel = NBody.private.vel;
     var pos = NBody.private.pos;
     var x = 0;
     var y = 0;
     var z = 0;
     var velX = vel[index][0];
     var velY = vel[index][1];
     var velZ = vel[index][2];
     var velX2 = vel[index][3];
     var velY2 = vel[index][4];
     var velZ2 = vel[index][5];
     var netX = (velX - velX2);
     var netY = (velY - velY2);
     var netZ = (velZ - velZ2);
     x = pos[index][0] + netX;
     y = pos[index][1] + netY;
     z = pos[index][2] + netZ;
     return [x, y, z];
   }
 };
 function emulateNBody(mode, numBodies, ticks) {
   NBody.init(mode, numBodies);
   for (var i = 0; i < ticks; i++) {
     var start = Date.now();
     if (mode === "par")
       NBody.tickPar();
     else
       NBody.tickSeq();
     //print(NBody.private.pos);
     print(mode + " bodies=" + numBodies + " tick=" + (i+1) + "/" + ticks + ": " + (Date.now() - start) + " ms");
   }
 }
 // Using 4000 bodies going off Rick's comment as 4000 being a typical workload.
 const NUMBODIES = 4000;
 const TICKS = 10;
 Math.seedrandom("seed");
 benchmark("NBODY", 1, DEFAULT_MEASURE,
           function () { emulateNBody("seq", NUMBODIES, TICKS); },
           function () { emulateNBody("par", NUMBODIES, TICKS); });