mirror of
https://github.com/josdejong/mathjs.git
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71 lines
2.6 KiB
JavaScript
71 lines
2.6 KiB
JavaScript
var assert = require('assert'),
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error = require('../../../lib/error/index'),
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math = require('../../../index'),
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approx = require('../../../tools/approx'),
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pi = math.pi,
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complex = math.complex,
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matrix = math.matrix,
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unit = math.unit,
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atan = math.atan,
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tan = math.tan;
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describe('atan', function() {
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it('should return the arctan of a boolean', function () {
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approx.equal(atan(true), 0.25 * pi);
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approx.equal(atan(false), 0);
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});
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it('should return the arctan of a number', function() {
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approx.equal(atan(-1) / pi, -0.25);
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approx.equal(atan(-0.5) / pi, -0.147583617650433);
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approx.equal(atan(0) / pi, 0);
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approx.equal(atan(0.5) / pi, 0.147583617650433);
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approx.equal(atan(1) / pi, 0.25);
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});
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it('should return the arctan of a bignumber (downgrades to number)', function() {
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approx.equal(atan(math.bignumber(1)), pi / 4);
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});
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it('should be the inverse function of tan', function() {
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approx.equal(atan(tan(-1)), -1);
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approx.equal(atan(tan(0)), 0);
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approx.equal(atan(tan(0.1)), 0.1);
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approx.equal(atan(tan(0.5)), 0.5);
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approx.equal(atan(tan(2)), -1.14159265358979);
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});
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it('should return the arctan of a complex number', function() {
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var re = 1.409921049596575,
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im = 0.229072682968539;
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approx.deepEqual(atan(complex('2+3i')), complex(re, im));
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approx.deepEqual(atan(complex('2-3i')), complex(re, -im));
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approx.deepEqual(atan(complex('-2+3i')), complex(-re, im));
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approx.deepEqual(atan(complex('-2-3i')), complex(-re, -im));
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approx.deepEqual(atan(complex('i')), complex(NaN, NaN)); // TODO: should return NaN + Infi instead
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approx.deepEqual(atan(complex('1')), complex(0.785398163397448, 0));
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approx.deepEqual(atan(complex('1+i')), complex(1.017221967897851, 0.402359478108525));
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});
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it('should throw an error if called with a unit', function() {
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assert.throws(function () {atan(unit('45deg'))});
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assert.throws(function () {atan(unit('5 celsius'))});
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});
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it('should throw an error if called with a string', function() {
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assert.throws(function () {atan('string')});
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});
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it('should calculate the arctan element-wise for arrays and matrices', function() {
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// matrix, array, range
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var atan123 = [0.785398163397448, 1.107148717794090, 1.249045772398254];
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approx.deepEqual(atan([1,2,3]), atan123);
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approx.deepEqual(atan(matrix([1,2,3])), matrix(atan123));
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});
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it('should throw an error in case of invalid number of arguments', function() {
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assert.throws(function () {atan()}, error.ArgumentsError);
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assert.throws(function () {atan(1, 2)}, error.ArgumentsError);
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});
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}); |