Fix-up signature for approximation.
diff --git a/Lib/rational.py b/Lib/rational.py
index 40b9163..d23f433 100755
--- a/Lib/rational.py
+++ b/Lib/rational.py
@@ -195,16 +195,17 @@
n, d = d, n
return cf
- @classmethod
- def approximate_from_float(cls, f, max_denominator):
- 'Best rational approximation to f with a denominator <= max_denominator'
+ def approximate(self, max_denominator):
+ 'Best rational approximation with a denominator <= max_denominator'
# XXX First cut at algorithm
# Still needs rounding rules as specified at
# http://en.wikipedia.org/wiki/Continued_fraction
- cf = cls.from_float(f).as_continued_fraction()
+ if self.denominator <= max_denominator:
+ return self
+ cf = self.as_continued_fraction()
result = Rational(0)
for i in range(1, len(cf)):
- new = cls.from_continued_fraction(cf[:i])
+ new = self.from_continued_fraction(cf[:i])
if new.denominator > max_denominator:
break
result = new
diff --git a/Lib/test/test_rational.py b/Lib/test/test_rational.py
index 20abce2..6ce7c35 100644
--- a/Lib/test/test_rational.py
+++ b/Lib/test/test_rational.py
@@ -155,10 +155,10 @@
[-4, 1, 6, 15, 1, 292, 1, 1, 1, 2, 1, 3, 1, 14, 3, 3])
self.assertEqual(R(0).as_continued_fraction(), [0])
- def testApproximateFromFloat(self):
- self.assertEqual(R.approximate_from_float(math.pi, 10000), R(355, 113))
- self.assertEqual(R.approximate_from_float(-math.pi, 10000), R(-355, 113))
- self.assertEqual(R.approximate_from_float(0.0, 10000), R(0))
+ def testApproximateFrom(self):
+ self.assertEqual(R.from_float(math.pi).approximate(10000), R(355, 113))
+ self.assertEqual(R.from_float(-math.pi).approximate(10000), R(-355, 113))
+ self.assertEqual(R.from_float(0.0).approximate(10000), R(0))
def testConversions(self):
self.assertTypedEquals(-1, trunc(R(-11, 10)))