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https://github.com/josdejong/mathjs.git
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8b2a6a13f3
Before the det function changed the original values of the input array/matrix. I fixed this problems and added tests to account for that. I additionally added some more tests and enforced the input to be an array or a matrix since determinants are not defined for other types
60 lines
1.8 KiB
JavaScript
60 lines
1.8 KiB
JavaScript
var assert = require('assert'),
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math = require('../../../index')();
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describe('det', function() {
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it('should calculate correctly the determinant of a NxN matrix', function() {
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assert.equal(math.det([5]), 5);
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assert.equal(math.det([[1,2],[3,4]]), -2);
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assert.equal(math.det(math.matrix([[1,2],[3,4]])), -2);
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assert.equal(math.det([
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[-2, 2, 3],
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[-1, 1, 3],
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[ 2, 0, -1]
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]), 6);
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assert.equal(math.det([
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[ 1, 4, 7],
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[ 3, 0, 5],
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[-1, 9, 11]
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]), -8);
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assert.equal(math.det([
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[1,7,4,3,7],
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[0,7,0,3,7],
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[0,7,4,3,0],
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[1,7,5,9,7],
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[2,7,4,3,7]
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]), -1176);
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assert.equal(math.det(math.diag([4,-5,6])), -120);
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});
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it('should return 1 for the identiy matrix',function() {
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assert.equal(math.det(math.eye(7)), 1);
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assert.equal(math.det(math.eye(2)), 1);
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assert.equal(math.det(math.eye(1)), 1);
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});
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it('should not change the value of the initial matrix', function() {
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var m_test = [[1,2,3],[4,5,6],[7,8,9]];
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math.det(m_test);
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assert.deepEqual(m_test, [[1,2,3],[4,5,6],[7,8,9]]);
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});
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it('should not accept a non-square matrix', function() {
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assert.throws(function() { math.det([1,2]); });
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assert.throws(function() { math.det([[1,2,3],[1,2,3]]); });
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assert.throws(function() { math.det([0,1],[0,1],[0,1]); });
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});
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it('should not accept other types than Matrix or Array', function() {
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assert.throws(function() { math.det(1); });
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assert.throws(function() { math.det(new BigNumber(10)); });
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assert.throws(function() { math.det(false); });
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});
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it('should not accept arrays with dimensions higher than 2', function() {
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assert.throws(function() { math.det([[[1]]]); });
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assert.throws(function() { math.det(math.matrix([[[1]]])); });
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});
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}); |