nxt.rational source code

1 /************************
2 
3 Boost Software License - Version 1.0 - August 17th, 2003
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5 Permission is hereby granted, free of charge, to any person or organization
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26 
27 ****************/
28 
29 module nxt.rational;
30 
31 template Tpl(T...){alias T Tpl;}
32 
33 ///
34 uint gcd(int n, uint d)
35 {
36     if(n < 0) n = -n;
37     while(d)
38     {
39         int t = d;
40         d = n%d;
41         n = t;
42     }
43     return n;
44 }
45 static assert(7 == gcd(14,21));
46 
47 ///
48 template Reduce(int n, uint d)
49 {
50     static assert(d != 0);
51     static if(n != 0)
52     {
53         //pragma(msg,n.stringof~"/"~d.stringof);
54         const int N =  n / cast(int)gcd(n,d);
55         const int D = cast(uint)(d / gcd(n,d));
56         const bool Reduced = (gcd(n,d) == 1);
57     }
58     else
59     {
60         const int N =  0;
61         const int D = 1;
62         const bool Reduced = (D == 1);
63     }
64     alias Tpl!(N,D) V;
65 }
66 
67 static assert(!Reduce!(-14,21).Reduced);
68 static assert( Reduce!(-16,21).Reduced);