lib/standard/math.nit

   1 # This file is part of NIT ( http://www.nitlanguage.org ).
   2 #
   3 # Copyright 2004-2008 Jean Privat <jean@pryen.org>
   4 #
   5 # This file is free software, which comes along with NIT.  This software is
   6 # distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
   7 # without  even  the implied warranty of  MERCHANTABILITY or  FITNESS FOR A
   8 # PARTICULAR PURPOSE.  You can modify it is you want,  provided this header
   9 # is kept unaltered, and a notification of the changes is added.
  10 # You  are  allowed  to  redistribute it and sell it, alone or is a part of
  11 # another product.
  12
  13 # Mathematical operations
  14 module math
  15
  16 import kernel
  17 import collection
  18
  19 in "C header" `{
  20 #include <math.h>
  21 `}
  22
  23 redef class Int
  24         # Returns a random `Int` in `[0 .. self[`.
  25         fun rand: Int is extern "kernel_Int_Int_rand_0"
  26         fun bin_and(i: Int): Int is extern "kernel_Int_Int_binand_0"
  27         fun bin_or(i: Int): Int is extern "kernel_Int_Int_binor_0"
  28         fun bin_xor(i: Int): Int is extern "kernel_Int_Int_binxor_0"
  29         fun sqrt: Int `{ return sqrt(recv); `}
  30         # Returns the greatest common divisor of `self` and `o`
  31         #
  32         #     assert 54.gcd(24)   == 6
  33         #     assert -54.gcd(-24) == 6
  34         #     assert 54.gcd(-24)  == -6
  35         #     assert -54.gcd(24)  == -6
  36         #     assert 12.gcd(6)    == 6
  37         fun gcd(o: Int): Int
  38         do
  39                 if self < 0 then return -(-self).gcd(o)
  40                 if o < 0 then return -(self.gcd(-o))
  41                 if self == 0 or o == self then return o
  42                 if o == 0 then return self
  43                 if self.bin_and(1) == 0 then
  44                         if o.bin_and(1) == 1 then
  45                                 return self.rshift(1).gcd(o)
  46                         else
  47                                 return self.rshift(1).gcd(o.rshift(1)).lshift(1)
  48                         end
  49                 end
  50                 if o.bin_and(1) == 0 then return self.gcd(o.rshift(1))
  51                 if self > o then return (self - o).rshift(1).gcd(o)
  52                 return (o - self).rshift(1).gcd(self)
  53         end
  54
  55         # Is `self` even ?
  56         #
  57         #    assert 12.is_even
  58         fun is_even: Bool do return self % 2 == 0
  59
  60         # Is `self` odd ?
  61         #
  62         #    assert not 13.is_even
  63         fun is_odd: Bool do return not is_even
  64 end
  65
  66 redef class Float
  67         fun sqrt: Float is extern "kernel_Float_Float_sqrt_0"
  68         fun cos: Float is extern "kernel_Float_Float_cos_0"
  69         fun sin: Float is extern "kernel_Float_Float_sin_0"
  70         fun tan: Float is extern "kernel_Float_Float_tan_0"
  71         fun acos: Float is extern "kernel_Float_Float_acos_0"
  72         fun asin: Float is extern "kernel_Float_Float_asin_0"
  73         fun atan: Float is extern "kernel_Float_Float_atan_0"
  74         fun abs: Float `{ return fabs(recv); `}
  75
  76         fun pow(e: Float): Float is extern "kernel_Float_Float_pow_1"
  77         fun log: Float is extern "kernel_Float_Float_log_0"
  78         fun exp: Float is extern "kernel_Float_Float_exp_0"
  79
  80         #     assert 1.1.ceil == 2.0
  81         #     assert 1.9.ceil == 2.0
  82         #     assert 2.0.ceil == 2.0
  83         #     assert (-1.5).ceil == -1.0
  84         fun ceil: Float `{ return ceil(recv); `}
  85
  86         #     assert 1.1.floor == 1.0
  87         #     assert 1.9.floor == 1.0
  88         #     assert 2.0.floor == 2.0
  89         #     assert (-1.5).floor == -2.0
  90         fun floor: Float `{ return floor(recv); `}
  91
  92         # Returns a random `Float` in `[0.0 .. self[`.
  93         fun rand: Float is extern "kernel_Float_Float_rand_0"
  94         fun hypot_with( b : Float ) : Float is extern "hypotf"
  95
  96         fun is_nan: Bool is extern "isnan"
  97
  98         # Is the float an infinite value
  99         # this function returns:
 100         #
 101         #  * 1 if self is positive infinity
 102         #  * -1 if self is negative infinity
 103         #  * 0 otherwise
 104         fun is_inf: Int do
 105                 if is_inf_extern then
 106                         if self < 0.0 then return -1
 107                         return 1
 108                 end
 109                 return 0
 110         end
 111
 112         private fun is_inf_extern: Bool is extern "isinf"
 113 end
 114
 115 redef class Collection[ E ]
 116         # Return a random element form the collection
 117         # There must be at least one element in the collection
 118         fun rand: E
 119         do
 120                 if is_empty then abort
 121                 var rand_index = length.rand
 122
 123                 for e in self do
 124                         if rand_index == 0 then return e
 125                         rand_index -= 1
 126                 end
 127                 abort
 128         end
 129 end
 130
 131 fun atan2(x: Float, y: Float): Float is extern "kernel_Any_Any_atan2_2"
 132 fun pi: Float is extern "kernel_Any_Any_pi_0"
 133 fun srand_from(x: Int) is extern "kernel_Any_Any_srand_from_1"
 134 fun srand is extern "kernel_Any_Any_srand_0"