diff options
Diffstat (limited to 'lib/pure/rationals.nim')
| -rw-r--r-- | lib/pure/rationals.nim | 32 |
1 files changed, 26 insertions, 6 deletions
diff --git a/lib/pure/rationals.nim b/lib/pure/rationals.nim index ab05bcc25..5f806bd70 100644 --- a/lib/pure/rationals.nim +++ b/lib/pure/rationals.nim @@ -40,16 +40,16 @@ func reduce*[T: SomeInteger](x: var Rational[T]) = reduce(r) doAssert r.num == 1 doAssert r.den == 2 - + if x.den == 0: + raise newException(DivByZeroDefect, "division by zero") let common = gcd(x.num, x.den) if x.den > 0: x.num = x.num div common x.den = x.den div common - elif x.den < 0: - x.num = -x.num div common - x.den = -x.den div common - else: - raise newException(DivByZeroDefect, "division by zero") + when T isnot SomeUnsignedInt: + if x.den < 0: + x.num = -x.num div common + x.den = -x.den div common func initRational*[T: SomeInteger](num, den: T): Rational[T] = ## Creates a new rational number with numerator `num` and denominator `den`. @@ -318,3 +318,23 @@ func hash*[T](x: Rational[T]): Hash = h = h !& hash(copy.num) h = h !& hash(copy.den) result = !$h + +func `^`*[T: SomeInteger](x: Rational[T], y: T): Rational[T] = + ## Computes `x` to the power of `y`. + ## + ## The exponent `y` must be an integer. Negative exponents are supported + ## but floating point exponents are not. + runnableExamples: + doAssert (-3 // 5) ^ 0 == (1 // 1) + doAssert (-3 // 5) ^ 1 == (-3 // 5) + doAssert (-3 // 5) ^ 2 == (9 // 25) + doAssert (-3 // 5) ^ -2 == (25 // 9) + + if y >= 0: + result.num = x.num ^ y + result.den = x.den ^ y + else: + result.num = x.den ^ -y + result.den = x.num ^ -y + # Note that all powers of reduced rationals are already reduced, + # so we don't need to call reduce() here |