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Commit experimental root fixing code.

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This commit is contained in:
Jürg Lehni 2011-07-05 01:13:58 +02:00
parent 4924d683e4
commit 8a2a9409bd
1 changed files with 13 additions and 4 deletions
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17
src/util/Numerical.js
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@ -176,11 +176,20 @@ var Numerical = new function() {
// This sqrt is safe, since Q3 >= 0, and thus Q >= 0
v1 = -2 * sqrt(Q);
v2 = b / 3;
// TODO: Improve these values using findRoot()!
function f(x) {
// Normalized, a * x = x:
return ((x + b) * x + c) * x + d;
}
function df(x) {
return (3 * x + 2 * b) * x + c;
}
function fix(t) {
return Numerical.findRoot(f, df, t, -10, 10, 32, Numerical.TOLERANCE);
}
return [
v1 * cos(theta / 3) - v2,
v1 * cos((theta + 2 * PI) / 3) - v2,
v1 * cos((theta - 2 * PI) / 3) - v2
fix(v1 * cos(theta / 3) - v2),
fix(v1 * cos((theta + 2 * PI) / 3) - v2),
fix(v1 * cos((theta - 2 * PI) / 3) - v2)
];
} else { // One real root
var A = -Math.pow(abs(R) + sqrt(R2 - Q3), 1 / 3);