javascript-algorithms/src/algorithms/math/complex-number/ComplexNumber.js at master · creativeclick/javascript-algorithms · GitHub

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importradianToDegreefrom'../radian/radianToDegree';

exportdefaultclassComplexNumber{
/**
 * z = re + im * i
 * z = radius * e^(i * phase)
 *
 * @param {number} [re]
 * @param {number} [im]
 */
constructor({ re =0, im =0}={}){
this.re=re;
this.im=im;
}

/**
 * @param {ComplexNumber|number} addend
 * @return {ComplexNumber}
 */
add(addend){
// Make sure we're dealing with complex number.
constcomplexAddend=this.toComplexNumber(addend);

returnnewComplexNumber({
re: this.re+complexAddend.re,
im: this.im+complexAddend.im,
});
}

/**
 * @param {ComplexNumber|number} subtrahend
 * @return {ComplexNumber}
 */
subtract(subtrahend){
// Make sure we're dealing with complex number.
constcomplexSubtrahend=this.toComplexNumber(subtrahend);

returnnewComplexNumber({
re: this.re-complexSubtrahend.re,
im: this.im-complexSubtrahend.im,
});
}

/**
 * @param {ComplexNumber|number} multiplicand
 * @return {ComplexNumber}
 */
multiply(multiplicand){
// Make sure we're dealing with complex number.
constcomplexMultiplicand=this.toComplexNumber(multiplicand);

returnnewComplexNumber({
re: this.re*complexMultiplicand.re-this.im*complexMultiplicand.im,
im: this.re*complexMultiplicand.im+this.im*complexMultiplicand.re,
});
}

/**
 * @param {ComplexNumber|number} divider
 * @return {ComplexNumber}
 */
divide(divider){
// Make sure we're dealing with complex number.
constcomplexDivider=this.toComplexNumber(divider);

// Get divider conjugate.
constdividerConjugate=this.conjugate(complexDivider);

// Multiply dividend by divider's conjugate.
constfinalDivident=this.multiply(dividerConjugate);

// Calculating final divider using formula (a + bi)(a − bi) = a^2 + b^2
constfinalDivider=(complexDivider.re**2)+(complexDivider.im**2);

returnnewComplexNumber({
re: finalDivident.re/finalDivider,
im: finalDivident.im/finalDivider,
});
}

/**
 * @param {ComplexNumber|number} number
 */
conjugate(number){
// Make sure we're dealing with complex number.
constcomplexNumber=this.toComplexNumber(number);

returnnewComplexNumber({
re: complexNumber.re,
im: -1*complexNumber.im,
});
}

/**
 * @return {number}
 */
getRadius(){
returnMath.sqrt((this.re**2)+(this.im**2));
}

/**
 * @param {boolean} [inRadians]
 * @return {number}
 */
getPhase(inRadians=true){
letphase=Math.atan(Math.abs(this.im)/Math.abs(this.re));

if(this.re<0&&this.im>0){
phase=Math.PI-phase;
}elseif(this.re<0&&this.im<0){
phase=-(Math.PI-phase);
}elseif(this.re>0&&this.im<0){
phase=-phase;
}elseif(this.re===0&&this.im>0){
phase=Math.PI/2;
}elseif(this.re===0&&this.im<0){
phase=-Math.PI/2;
}elseif(this.re<0&&this.im===0){
phase=Math.PI;
}elseif(this.re>0&&this.im===0){
phase=0;
}elseif(this.re===0&&this.im===0){
// More correctly would be to set 'indeterminate'.
// But just for simplicity reasons let's set zero.
phase=0;
}

if(!inRadians){
phase=radianToDegree(phase);
}

returnphase;
}

/**
 * @param {boolean} [inRadians]
 * @return {{radius: number, phase: number}}
 */
getPolarForm(inRadians=true){
return{
radius: this.getRadius(),
phase: this.getPhase(inRadians),
};
}

/**
 * Convert real numbers to complex number.
 * In case if complex number is provided then lefts it as is.
 *
 * @param {ComplexNumber|number} number
 * @return {ComplexNumber}
 */
toComplexNumber(number){
if(numberinstanceofComplexNumber){
returnnumber;
}

returnnewComplexNumber({re: number});
}
}