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Commit e252eb6

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Add polar representation of complex numbers.
1 parent 096d5a8 commit e252eb6

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2 files changed

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‎src/algorithms/math/complex-number/ComplexNumber.js‎

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Original file line numberDiff line numberDiff line change
@@ -1,5 +1,10 @@
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import radianToDegree from '../radian/radianToDegree';
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export default class ComplexNumber {
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/**
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* z = re + im * i
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* z = radius * e^(i * phase)
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*
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* @param {number} [re]
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* @param {number} [im]
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*/
@@ -70,4 +75,44 @@ export default class ComplexNumber {
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im: -1 * complexNumber.im,
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});
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}
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/**
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* @return {number}
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*/
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getRadius() {
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return Math.sqrt((this.re ** 2) + (this.im ** 2));
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}
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/**
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* @param {boolean} [inRadians]
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* @return {number}
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*/
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getPhase(inRadians = true) {
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let phase = Math.atan(Math.abs(this.im) / Math.abs(this.re));
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if (this.re < 0 && this.im > 0) {
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phase = Math.PI - phase;
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} else if (this.re < 0 && this.im < 0) {
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phase = -(Math.PI - phase);
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} else if (this.re > 0 && this.im < 0) {
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phase = -phase;
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}
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if (!inRadians) {
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phase = radianToDegree(phase);
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}
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return phase;
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}
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/**
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* @param {boolean} [inRadians]
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* @return {{radius: number, phase: number}}
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*/
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getPolarForm(inRadians = true) {
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return {
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radius: this.getRadius(),
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phase: this.getPhase(inRadians),
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};
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}
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}

‎src/algorithms/math/complex-number/__test__/ComplexNumber.test.js‎

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@@ -110,4 +110,31 @@ describe('ComplexNumber', () => {
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expect(complexNumber3.re).toBe(-7 / 41);
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expect(complexNumber3.im).toBe(22 / 41);
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});
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it('should return complex number in polar form', () => {
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const complexNumber1 = new ComplexNumber({ re: 3, im: 3 });
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expect(complexNumber1.getPolarForm().radius).toBe(Math.sqrt((3 ** 2) + (3 ** 2)));
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expect(complexNumber1.getPolarForm().phase).toBe(Math.PI / 4);
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expect(complexNumber1.getPolarForm(false).phase).toBe(45);
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const complexNumber2 = new ComplexNumber({ re: -3, im: 3 });
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expect(complexNumber2.getPolarForm().radius).toBe(Math.sqrt((3 ** 2) + (3 ** 2)));
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expect(complexNumber2.getPolarForm().phase).toBe(3 * (Math.PI / 4));
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expect(complexNumber2.getPolarForm(false).phase).toBe(135);
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const complexNumber3 = new ComplexNumber({ re: -3, im: -3 });
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expect(complexNumber3.getPolarForm().radius).toBe(Math.sqrt((3 ** 2) + (3 ** 2)));
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expect(complexNumber3.getPolarForm().phase).toBe(-3 * (Math.PI / 4));
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expect(complexNumber3.getPolarForm(false).phase).toBe(-135);
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const complexNumber4 = new ComplexNumber({ re: 3, im: -3 });
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expect(complexNumber4.getPolarForm().radius).toBe(Math.sqrt((3 ** 2) + (3 ** 2)));
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expect(complexNumber4.getPolarForm().phase).toBe(-1 * (Math.PI / 4));
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expect(complexNumber4.getPolarForm(false).phase).toBe(-45);
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const complexNumber5 = new ComplexNumber({ re: 5, im: 7 });
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expect(complexNumber5.getPolarForm().radius).toBeCloseTo(8.60);
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expect(complexNumber5.getPolarForm().phase).toBeCloseTo(0.95);
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expect(complexNumber5.getPolarForm(false).phase).toBeCloseTo(54.46);
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});
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});

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