lib/standard: call srand by default

[nit.git] / lib / standard / math.nit

diff --git a/lib/standard/math.nit b/lib/standard/math.nit
index 3ea931a..9d2b2bf 100644 (file)
--- a/lib/standard/math.nit
+++ b/lib/standard/math.nit
@@ -23,10 +23,94 @@ in "C header" `{
 redef class Int
        # Returns a random `Int` in `[0 .. self[`.
        fun rand: Int is extern "kernel_Int_Int_rand_0"
+
+       # Returns the result of a binary AND operation on `self` and `i`
+       #
+       #    assert 0x10.bin_and(0x01) == 0
        fun bin_and(i: Int): Int is extern "kernel_Int_Int_binand_0"
+
+       # Returns the result of a binary OR operation on `self` and `i`
+       #
+       #    assert 0x10.bin_or(0x01) == 0x11
        fun bin_or(i: Int): Int is extern "kernel_Int_Int_binor_0"
+
+       # Returns the result of a binary XOR operation on `self` and `i`
+       #
+       #    assert 0x101.bin_xor(0x110) == 0x11
        fun bin_xor(i: Int): Int is extern "kernel_Int_Int_binxor_0"
-       fun sqrt : Int is extern `{ return sqrtl(recv); `}
+
+       # Returns the 1's complement of `self`
+       #
+       #    assert 0x2F.bin_not == -48
+       fun bin_not: Int is extern "kernel_Int_Int_binnot_0"
+
+       # Returns the square root of `self`
+       #
+       #    assert 16.sqrt == 4
+       fun sqrt: Int `{ return sqrt(recv); `}
+
+       # Returns the greatest common divisor of `self` and `o`
+       #
+       #     assert 54.gcd(24)   == 6
+       #     assert -54.gcd(-24) == 6
+       #     assert 54.gcd(-24)  == -6
+       #     assert -54.gcd(24)  == -6
+       #     assert 12.gcd(6)    == 6
+       fun gcd(o: Int): Int
+       do
+               if self < 0 then return -(-self).gcd(o)
+               if o < 0 then return -(self.gcd(-o))
+               if self == 0 or o == self then return o
+               if o == 0 then return self
+               if self.bin_and(1) == 0 then
+                       if o.bin_and(1) == 1 then
+                               return self.rshift(1).gcd(o)
+                       else
+                               return self.rshift(1).gcd(o.rshift(1)).lshift(1)
+                       end
+               end
+               if o.bin_and(1) == 0 then return self.gcd(o.rshift(1))
+               if self > o then return (self - o).rshift(1).gcd(o)
+               return (o - self).rshift(1).gcd(self)
+       end
+
+       # Is `self` even ?
+       #
+       #    assert 12.is_even
+       fun is_even: Bool do return self % 2 == 0
+
+       # Is `self` odd ?
+       #
+       #    assert not 13.is_even
+       fun is_odd: Bool do return not is_even
+
+       # Returns the `self` raised to the power of `e`.
+       #
+       #    assert 2 ** 3 == 8
+       fun **(e: Int): Int
+       do
+               return self.to_f.pow(e.to_f).to_i
+       end
+
+       # The factorial of `self` (aka `self!`)
+       #
+       # Returns `1 * 2 * 3 * ... * self-1 * self`
+       #
+       #    assert 0.factorial == 1  # by convention for an empty product
+       #    assert 1.factorial == 1
+       #    assert 4.factorial == 24
+       #    assert 9.factorial == 362880
+       fun factorial: Int
+       do
+               assert self >= 0
+               var res = 1
+               var n = self
+               while n > 0 do
+                       res = res * n
+                       n -= 1
+               end
+               return res
+       end
 end
 
 redef class Float
@@ -42,6 +126,18 @@ redef class Float
        fun pow(e: Float): Float is extern "kernel_Float_Float_pow_1"
        fun log: Float is extern "kernel_Float_Float_log_0"
        fun exp: Float is extern "kernel_Float_Float_exp_0"
+
+       #     assert 1.1.ceil == 2.0
+       #     assert 1.9.ceil == 2.0
+       #     assert 2.0.ceil == 2.0
+       #     assert (-1.5).ceil == -1.0
+       fun ceil: Float `{ return ceil(recv); `}
+
+       #     assert 1.1.floor == 1.0
+       #     assert 1.9.floor == 1.0
+       #     assert 2.0.floor == 2.0
+       #     assert (-1.5).floor == -2.0
+       fun floor: Float `{ return floor(recv); `}
        
        # Returns a random `Float` in `[0.0 .. self[`.
        fun rand: Float is extern "kernel_Float_Float_rand_0"
@@ -82,6 +178,13 @@ redef class Collection[ E ]
        end
 end
 
+redef class Sys
+       init
+       do
+               srand
+       end
+end
+
 fun atan2(x: Float, y: Float): Float is extern "kernel_Any_Any_atan2_2"
 fun pi: Float is extern "kernel_Any_Any_pi_0"
 fun srand_from(x: Int) is extern "kernel_Any_Any_srand_from_1"