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Optimizations #32

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Optimizations #32

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2 changes: 1 addition & 1 deletion src/matrix.js
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Original file line number Diff line number Diff line change
Expand Up @@ -271,7 +271,7 @@ Sylvester.Matrix.prototype = {
if (!this.isSquare) { return null; }
var els = [], n = this.elements.length;
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@zbjornson You know the length already in a lot these cases, you should use new Array(n) and then set the indexs x[i] = <val>

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@megawac that actually seems detrimental in some browsers and only a minor improvement in others: http://jsperf.com/construct-array-of-fixed-size/2

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(Specifically, I optimized for FF and chrome, and the gain in FF doesn't outweigh the loss in chrome.)

for (var i = 0; i < n; i++) {
els.push(this.elements[i][i]);
els[i] = this.elements[i][i];
}
return Sylvester.Vector.create(els);
},
Expand Down
37 changes: 22 additions & 15 deletions src/vector.js
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Original file line number Diff line number Diff line change
Expand Up @@ -8,13 +8,13 @@ var $V = Sylvester.Vector.create;

Sylvester.Vector.Random = function(n) {
var elements = [];
while (n--) { elements.push(Math.random()); }
while (n--) { elements[n] = Math.random(); }
return Sylvester.Vector.create(elements);
};

Sylvester.Vector.Zero = function(n) {
var elements = [];
while (n--) { elements.push(0); }
while (n--) { elements[n] = 0; }
return Sylvester.Vector.create(elements);
};

Expand Down Expand Up @@ -48,7 +48,7 @@ Sylvester.Vector.prototype = {
map: function(fn, context) {
var elements = [];
this.each(function(x, i) {
elements.push(fn.call(context, x, i));
elements[i] = fn.call(context, x, i);
});
return Sylvester.Vector.create(elements);
},
Expand Down Expand Up @@ -107,13 +107,18 @@ Sylvester.Vector.prototype = {
},

subtract: function(vector) {
var V = vector.elements || vector;
if (this.elements.length !== V.length) { return null; }
return this.map(function(x, i) { return x - V[i-1]; });
var V = vector.elements || vector,
m = this.elements.length;
if (m !== V.length) { return null; }
var te = this.elements, elements = [];
while (m--) { elements[m] = te[m] - V[m]; }
return Sylvester.Vector.create(elements);
},

multiply: function(k) {
return this.map(function(x) { return x*k; });
var te = this.elements, m = te.length, elements = [];
while (m--) { elements[m] = te[m] * k; }
return Sylvester.Vector.create(elements);
},

dot: function(vector) {
Expand All @@ -136,17 +141,17 @@ Sylvester.Vector.prototype = {
},

max: function() {
var m = 0, i = this.elements.length;
var m = 0, te = this.elements, i = te.length;
while (i--) {
if (Math.abs(this.elements[i]) > Math.abs(m)) { m = this.elements[i]; }
if (Math.abs(te[i]) > Math.abs(m)) { m = te[i]; }
}
return m;
},

indexOf: function(x) {
var index = null, n = this.elements.length;
var index = null, te = this.elements, n = te.length;
for (var i = 0; i < n; i++) {
if (index === null && this.elements[i] === x) {
if (index === null && te[i] === x) {
index = i + 1;
}
}
Expand All @@ -158,13 +163,15 @@ Sylvester.Vector.prototype = {
},

round: function() {
return this.map(function(x) { return Math.round(x); });
var te = this.elements, m = te.length, elements = [];
while (m--) { elements[m] = Math.round(te[m]); }
return Sylvester.Vector.create(elements);
},

snapTo: function(x) {
return this.map(function(y) {
return (Math.abs(y - x) <= Sylvester.precision) ? x : y;
});
var te = this.elements, m = te.length, elements = [];
while (m--) { elements[m] = (Math.abs(te[m] - x) <= Sylvester.precision) ? x : te[m]; }
return Sylvester.Vector.create(elements);
},

distanceFrom: function(obj) {
Expand Down