Guido van Rossum | e876949 | 1992-08-13 12:14:11 +0000 | [diff] [blame] | 1 | # Complex numbers |
| 2 | |
| 3 | |
| 4 | from math import sqrt |
| 5 | |
| 6 | |
| 7 | def complex(re, im): |
| 8 | return Complex().init(re, im) |
| 9 | |
| 10 | |
| 11 | class Complex: |
| 12 | |
| 13 | def init(self, re, im): |
| 14 | self.re = float(re) |
| 15 | self.im = float(im) |
| 16 | return self |
| 17 | |
| 18 | def __repr__(self): |
| 19 | return 'complex' + `self.re, self.im` |
| 20 | |
| 21 | def __cmp__(a, b): |
| 22 | a = a.__abs__() |
| 23 | b = b.__abs__() |
| 24 | return (a > b) - (a < b) |
| 25 | |
| 26 | def __float__(self): |
| 27 | if self.im: |
| 28 | raise ValueError, 'cannot convert complex to float' |
| 29 | return float(self.re) |
| 30 | |
| 31 | def __long__(self): |
| 32 | return long(float(self)) |
| 33 | |
| 34 | def __int__(self): |
| 35 | return int(float(self)) |
| 36 | |
| 37 | def __abs__(self): |
| 38 | # XXX overflow? |
| 39 | return sqrt(self.re*self.re + self.im*self.im) |
| 40 | |
| 41 | def __add__(a, b): |
| 42 | return complex(a.re + b.re, a.im + b.im) |
| 43 | |
| 44 | def __sub__(a, b): |
| 45 | return complex(a.re - b.re, a.im - b.im) |
| 46 | |
| 47 | def __mul__(a, b): |
| 48 | return complex(a.re*b.re - a.im*b.im, a.re*b.im + a.im*b.re) |
| 49 | |
| 50 | def __div__(a, b): |
| 51 | q = (b.re*b.re + b.im*b.im) |
| 52 | re = (a.re*b.re + a.im*b.im) / q |
| 53 | im = (a.im*b.re - b.im*a.re) / q |
| 54 | return complex(re, im) |
| 55 | |
| 56 | def __neg__(self): |
| 57 | return complex(-self.re, -self.im) |
| 58 | |
| 59 | |
| 60 | def test(): |
| 61 | a = complex(2, 0) |
| 62 | b = complex(3, 4) |
| 63 | print a, b |
| 64 | print a+b, a-b, a*b, a/b |
| 65 | print b+a, b-a, b*a, b/a |
| 66 | i = complex(0, 1) |
| 67 | print i, i*i, i*i*i, i*i*i*i |
| 68 | j = complex(1, 1) |
| 69 | print j, j*j, j*j*j, j*j*j*j |
| 70 | print abs(j), abs(j*j), abs(j*j*j), abs(j*j*j*j) |
| 71 | print i/-i |
| 72 | |
| 73 | test() |