Math/Complex.bruijn

# ideas by u/DaVinci103
# MIT License, Copyright (c) 2024 Marvin Borner

:import std/Combinator .
:import std/Pair .
:import std/Math/Real R

ι (+0.0+1.0i)

# converts a balanced ternary number to a complex number
number→complex [[0 (R.number→real 1) (+0.0r)]] ⧗ Number → Complex

:test (number→complex (+5)) ((+5.0+0.0i))

# returns real part of a complex number
real fst ⧗ Complex → Real

:test (real (+5.0+2.0i)) ((+5.0r))

# returns imaginary part of a complex number
imag snd ⧗ Complex → Real

:test (imag (+5.0+2.0i)) ((+2.0r))

# approximates complex number by turning it into a pair of rationals
approx &[[[(2 0) : (1 0)]]] ⧗ Complex → Number → (Pair Rational Rational)

:test (approx (+5.0+2.0i) (+2)) ((+5.0q) : (+2.0q))

# returns true if two complex numbers are equal approximately
approx-eq? [[[R.approx-eq? 2 (1 2) (0 2)]]] ⧗ Number → Complex → Complex → Boolean

# TODO: bigger value (higher performance first!)
…≈?… approx-eq? (+1000)

# adds two complex numbers
add &[[&[[(R.add 3 1) : (R.add 2 0)]]]] ⧗ Complex → Complex → Complex

…+… add

# subtracts two complex numbers
sub &[[&[[(R.sub 3 1) : (R.sub 2 0)]]]] ⧗ Complex → Complex → Complex

…+… sub

# multiplies two complex numbers
mul &[[&[[p : q]]]] ⧗ Complex → Complex → Complex
	p R.sub (R.mul 3 1) (R.mul 2 0)
	q R.add (R.mul 3 0) (R.mul 2 1)

…⋅… mul

# divides two complex numbers
div &[[&[[p : q]]]] ⧗ Complex → Complex → Complex
	p R.div (R.add (R.mul 3 1) (R.mul 2 0)) (R.add (R.mul 1 1) (R.mul 0 0))
	q R.div (R.sub (R.mul 2 1) (R.mul 1 0)) (R.add (R.mul 1 1) (R.mul 0 0))

…/… div

# negates a complex number
negate &[[(R.negate 1) : (R.negate 0)]] ⧗ Complex → Complex

-‣ negate

# inverts a complex number
invert &[[p : q]] ⧗ Complex → Complex
	p R.div 1 (R.add (R.mul 1 1) (R.mul 0 0))
	q R.div 0 (R.add (R.mul 1 1) (R.mul 0 0))

~‣ invert

# ---

:import std/List L

# power function: complex^number
pow-n [L.nth-iterate (mul 0) (+1.0+0.0i)] ⧗ Complex → Number → Complex

ln [p : q] ⧗ Complex → Complex
	p R.ln (&R.hypot 0)
	q &R.atan2 0