typocomath/src/Complex/arithmetic.ts

130 lines
4.0 KiB
TypeScript

import {Complex, complex_binary, FnComplexUnary} from './type.js'
import type {
FnAbsSquare,
FnAdd,
FnAddReal,
FnConj, FnConservativeSqrt, FnDivide,
FnDivideByReal, FnIsReal, FnIsSquare,
FnMultiply, FnNaN, FnRe, FnReciprocal, FnSqrt,
FnSubtract,
FnUnaryMinus, FnZero
} from '../interfaces/arithmetic'
export const add =
<T>(dep: {
add: FnAdd<T>
}): FnAdd<Complex<T>> =>
(w, z) => complex_binary(dep.add(w.re, z.re), dep.add(w.im, z.im))
export const addReal =
<T>(dep: {
addReal: FnAddReal<T, T>
}): FnAddReal<Complex<T>, T> =>
(z, r) => complex_binary(dep.addReal(z.re, r), z.im)
export const unaryMinus =
<T>(dep: {
unaryMinus: FnUnaryMinus<T>
}): FnUnaryMinus<Complex<T>> =>
(z) => complex_binary(dep.unaryMinus(z.re), dep.unaryMinus(z.im))
export const conj =
<T>(dep: {
unaryMinus: FnUnaryMinus<T>,
conj: FnConj<T>
}) : FnConj<Complex<T>> =>
(z) => complex_binary(dep.conj(z.re), dep.unaryMinus(z.im))
export const subtract =
<T>(dep: {
subtract: FnSubtract<T>
}): FnSubtract<Complex<T>> =>
(w, z) => complex_binary(dep.subtract(w.re, z.re), dep.subtract(w.im, z.im))
export const multiply =
<T>(dep: {
add: FnAdd<T>,
subtract: FnSubtract<T>,
multiply: FnMultiply<T>,
conj: FnConj<T>
}) =>
(w, z) => {
const mult = dep.multiply
const realpart = dep.subtract(mult(w.re, z.re), mult(dep.conj(w.im), z.im))
const imagpart = dep.add(mult(dep.conj(w.re), z.im), mult(w.im, z.re))
return complex_binary(realpart, imagpart)
}
export const absquare =
<T, U>(dep: {
add: FnAdd<U>,
absquare: FnAbsSquare<T, U>
}): FnAbsSquare<Complex<T>, U> =>
(z) => dep.add(dep.absquare(z.re), dep.absquare(z.im))
export const divideByReal =
<T>(dep: {
divideByReal: FnDivideByReal<T, T>
}): FnDivideByReal<Complex<T>, T> =>
(z, r) => complex_binary(dep.divideByReal(z.re, r), dep.divideByReal(z.im, r))
export const reciprocal =
<T>(dep: {
conj: FnConj<Complex<T>>,
absquare: FnAbsSquare<Complex<T>, T>,
divideByReal: FnDivideByReal<Complex<T>, T>
}): FnReciprocal<Complex<T>> =>
(z) => dep.divideByReal(dep.conj(z), dep.absquare(z))
export const divide =
<T>(dep: {
multiply: FnMultiply<Complex<T>>,
reciprocal: FnReciprocal<Complex<T>>,
}): FnDivide<Complex<T>> =>
(w, z) => dep.multiply(w, dep.reciprocal(z))
export const complexSqrt =
<T>(dep: {
conservativeSqrt: FnConservativeSqrt<T>,
isSquare: FnIsSquare<T>,
complex: FnComplexUnary<T>,
unaryMinus: FnUnaryMinus<T>,
zero: FnZero<T>,
nan: FnNaN<Complex<T>>
}) =>
(r) => {
if (dep.isSquare(r)) return dep.complex(dep.conservativeSqrt(r))
const negative = dep.unaryMinus(r)
if (dep.isSquare(negative)) {
return complex_binary(
dep.zero(r), dep.conservativeSqrt(negative))
}
// neither the real number or its negative is a square; could happen
// for example with bigint. So there is no square root. So we have to
// return the NaN of the type.
return dep.nan(dep.complex(r))
}
export const sqrt =
<T>(dep: {
isReal: FnIsReal<Complex<T>>,
complexSqrt: FnSqrt<T>,
conservativeSqrt: FnConservativeSqrt<T>,
absquare: FnAbsSquare<Complex<T>, T>,
addReal: FnAddReal<Complex<T>, T>,
divideByReal: FnDivideByReal<Complex<T>, T>,
add: FnAdd<T>,
re: FnRe<Complex<T>, T>,
}) =>
(z: Complex<T>): Complex<T> | T => {
if (dep.isReal(z)) return dep.complexSqrt(z.re)
const myabs = dep.conservativeSqrt(dep.absquare(z))
const num = dep.addReal(z, myabs)
const r = dep.re(z)
const denomsq = dep.add(dep.add(myabs, myabs), dep.add(r, r))
const denom = dep.conservativeSqrt(denomsq)
return dep.divideByReal(num, denom)
}
export const conservativeSqrt = sqrt