Rename the functions consistently

Author: rhettinger

Lib/statistics.py

@@ -313,11 +313,11 @@ def _isqrt_frac_rto(n: int, m: int) -> float:
     return a | (a*a*m != n)
 
 
-# For 53 bit precision floats, the _sqrt_frac() shift is 109.
+# For 53 bit precision floats, the _float_sqrt_of_frac() shift is 109.
 _sqrt_shift: int = 2 * sys.float_info.mant_dig + 3
 
 
-def _sqrt_frac(n: int, m: int) -> float:
+def _float_sqrt_of_frac(n: int, m: int) -> float:
     """Square root of n/m as a float, correctly rounded."""
     # See principle and proof sketch at: https://bugs.python.org/msg407078
     q = (n.bit_length() - m.bit_length() - _sqrt_shift) // 2
@@ -330,7 +330,7 @@ def _sqrt_frac(n: int, m: int) -> float:
     return numerator / denominator   # Convert to float
 
 
-def _deci_sqrt(n: int, m: int) -> Decimal:
+def _decimal_sqrt_of_frac(n: int, m: int) -> Decimal:
     """Square root of n/m as a float, correctly rounded."""
     # Premise:  For decimal, computing sqrt(m / n) can be off by 1 ulp.
     # Method:   Check the result, moving up or down a step if needed.
@@ -895,7 +895,7 @@ def stdev(data, xbar=None):
     if hasattr(T, 'sqrt'):
         var = _convert(mss, T)
         return var.sqrt()
-    return _sqrt_frac(mss.numerator, mss.denominator)
+    return _float_sqrt_of_frac(mss.numerator, mss.denominator)
 
 
 def pstdev(data, mu=None):
@@ -915,8 +915,8 @@ def pstdev(data, mu=None):
     T, ss = _ss(data, mu)
     mss = ss / n
     if issubclass(T, Decimal):
-        return _deci_sqrt(mss.numerator, mss.denominator)
-    return _sqrt_frac(mss.numerator, mss.denominator)
+        return _decimal_sqrt_of_frac(mss.numerator, mss.denominator)
+    return _float_sqrt_of_frac(mss.numerator, mss.denominator)
 
 
 # === Statistics for relations between two inputs ===

Lib/test/test_statistics.py

@@ -2177,7 +2177,7 @@ def test_isqrt_frac_rto(self):
             self.assertTrue(m * (r - 1)**2 < n < m * (r + 1)**2)
 
     @requires_IEEE_754
-    def test_sqrt_frac(self):
+    def test_float_sqrt_of_frac(self):
 
         def is_root_correctly_rounded(x: Fraction, root: float) -> bool:
             if not x:
@@ -2204,24 +2204,24 @@ def is_root_correctly_rounded(x: Fraction, root: float) -> bool:
             denonimator: int = randrange(10 ** randrange(50)) + 1
             with self.subTest(numerator=numerator, denonimator=denonimator):
                 x: Fraction = Fraction(numerator, denonimator)
-                root: float = statistics._sqrt_frac(numerator, denonimator)
+                root: float = statistics._float_sqrt_of_frac(numerator, denonimator)
                 self.assertTrue(is_root_correctly_rounded(x, root))
 
         # Verify that corner cases and error handling match math.sqrt()
-        self.assertEqual(statistics._sqrt_frac(0, 1), 0.0)
+        self.assertEqual(statistics._float_sqrt_of_frac(0, 1), 0.0)
         with self.assertRaises(ValueError):
-            statistics._sqrt_frac(-1, 1)
+            statistics._float_sqrt_of_frac(-1, 1)
         with self.assertRaises(ValueError):
-            statistics._sqrt_frac(1, -1)
+            statistics._float_sqrt_of_frac(1, -1)
 
         # Error handling for zero denominator matches that for Fraction(1, 0)
         with self.assertRaises(ZeroDivisionError):
-            statistics._sqrt_frac(1, 0)
+            statistics._float_sqrt_of_frac(1, 0)
 
         # The result is well defined if both inputs are negative
-        self.assertEqual(statistics._sqrt_frac(-2, -1), statistics._sqrt_frac(2, 1))
+        self.assertEqual(statistics._float_sqrt_of_frac(-2, -1), statistics._float_sqrt_of_frac(2, 1))
 
-    def test_deci_sqrt(self):
+    def test_decimal_sqrt_of_frac(self):
         root: Decimal
         numerator: int
         denominator: int
@@ -2232,7 +2232,7 @@ def test_deci_sqrt(self):
             (Decimal('0.8500554152289934068192208727'), 722594208960136395984391238251, 1000000000000000000000000000000),  # Adj down
         ]:
             with decimal.localcontext(decimal.DefaultContext):
-                self.assertEqual(statistics._deci_sqrt(numerator, denominator), root)
+                self.assertEqual(statistics._decimal_sqrt_of_frac(numerator, denominator), root)
 
             # Confirm expected root with a quad precision decimal computation
             with decimal.localcontext(decimal.DefaultContext) as ctx:
@@ -2243,18 +2243,18 @@ def test_deci_sqrt(self):
             self.assertEqual(root, target_root)
 
         # Verify that corner cases and error handling match Decimal.sqrt()
-        self.assertEqual(statistics._deci_sqrt(0, 1), 0.0)
+        self.assertEqual(statistics._decimal_sqrt_of_frac(0, 1), 0.0)
         with self.assertRaises(decimal.InvalidOperation):
-            statistics._deci_sqrt(-1, 1)
+            statistics._decimal_sqrt_of_frac(-1, 1)
         with self.assertRaises(decimal.InvalidOperation):
-            statistics._deci_sqrt(1, -1)
+            statistics._decimal_sqrt_of_frac(1, -1)
 
         # Error handling for zero denominator matches that for Fraction(1, 0)
         with self.assertRaises(ZeroDivisionError):
-            statistics._deci_sqrt(1, 0)
+            statistics._decimal_sqrt_of_frac(1, 0)
 
         # The result is well defined if both inputs are negative
-        self.assertEqual(statistics._deci_sqrt(-2, -1), statistics._deci_sqrt(2, 1))
+        self.assertEqual(statistics._decimal_sqrt_of_frac(-2, -1), statistics._decimal_sqrt_of_frac(2, 1))
 
 
 class TestStdev(VarianceStdevMixin, NumericTestCase):