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Merge pull request #330 from FSMaxB/abs-fix

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Fix #328 abs(0+0*i) evaluates to NaN
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Jos de Jong 2015-04-22 15:02:24 +02:00
commit 95c4e33f81
2 changed files with 12 additions and 0 deletions
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6
lib/function/arithmetic/abs.js
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@ -49,6 +49,12 @@ module.exports = function (math) {
// do not compute sqrt(re * re + im * im) since it will overflow with big numbers!
var re = Math.abs(x.re);
var im = Math.abs(x.im);
if (re == 0) {
return im;
}
if (im == 0) {
return re;
}
if (re >= im) {
var i = im / re;
return re * Math.sqrt(1 + i * i);

6
test/function/arithmetic/abs.test.js
View File

@ -32,6 +32,12 @@ describe('abs', function () {
assert.equal(math.norm(math.complex(-4e200, 1e200)), 4.12310562561766e+200);
});
it('should return the absolute number of a complex number with zero', function () {
assert.equal(math.abs(math.complex(1, 0)), 1);
assert.equal(math.abs(math.complex(0, 1)), 1);
assert.equal(math.abs(math.complex(0, 0)), 0);
});
it('should return the absolute value of all elements in a matrix', function () {
var a1 = math.abs(math.matrix([1,-2,3]));
assert.ok(a1 instanceof math.type.Matrix);