Support for mathematical operations on dimensionless (but not simplified quantities)

fixes #45

4 files changed, 62 insertions, 32 deletions

diff --git a/CHANGES b/CHANGES
index b9a3303..49a41fa 100644
--- a/CHANGES
+++ b/CHANGES
@@ -25,7 +25,8 @@ Pint Changelog
   (Issue #42)
 - support for application of numpy function on non-ndarray magnitudes.
   (Issue #44)
-
+- support for math operations on dimensionless Quantities (writen with units)
+  (Issue #45)
 
 0.2.1 (2013-07-02)
 ------------------
diff --git a/pint/quantity.py b/pint/quantity.py
index 68673af..2cd9d11 100644
--- a/pint/quantity.py
+++ b/pint/quantity.py
@@ -213,12 +213,12 @@ class _Quantity(object):
     # Mathematical operations
     def __float__(self):
         if self.dimensionless:
-            return float(self._magnitude)
+            return float(self._REGISTRY.convert(self._magnitude, self.units, UnitsContainer()))
         raise DimensionalityError(self.units, 'dimensionless')
 
     def __complex__(self):
         if self.dimensionless:
-            return complex(self._magnitude)
+            return complex(self._REGISTRY.convert(self._magnitude, self.units, UnitsContainer()))
         raise DimensionalityError(self.units, 'dimensionless')
 
     def iadd_sub(self, other, fun):
@@ -378,7 +378,7 @@ class _Quantity(object):
     __nonzero__ = __bool__
 
     # NumPy Support
-
+    __radian = 'radian'
     __same_units = 'equal greater greater_equal less less_equal not_equal arctan2'.split()
     #: Dictionary mapping ufunc/attributes names to the units that they
     #: require (conversion will be tried).
@@ -387,23 +387,23 @@ class _Quantity(object):
                        'arccosh': '', 'arcsinh': '', 'arctanh': '',
                        'exp': '', 'expm1': '', 'exp2': '',
                        'log': '', 'log10': '', 'log1p': '', 'log2': '',
-                       'sin': 'radian', 'cos': 'radian', 'tan': 'radian',
-                       'sinh': 'radian', 'cosh': 'radian', 'tanh': 'radian',
-                       'radians': 'degree', 'degrees': 'radian',
-                       'deg2rad': 'degree', 'rad2deg': 'radian',
+                       'sin': __radian, 'cos': __radian, 'tan': __radian,
+                       'sinh': __radian, 'cosh': __radian, 'tanh': __radian,
+                       'radians': 'degree', 'degrees': __radian,
+                       'deg2rad': 'degree', 'rad2deg': __radian,
                        'logaddexp': '', 'logaddexp2': ''}
 
     #: Dictionary mapping ufunc/attributes names to the units that they
     #: will set on output.
     __set_units = {'cos': '', 'sin': '', 'tan': '',
                    'cosh': '', 'sinh': '', 'tanh': '',
-                   'arccos': 'radian', 'arcsin': 'radian',
-                   'arctan': 'radian', 'arctan2': 'radian',
-                   'arccosh': 'radian', 'arcsinh': 'radian',
-                   'arctanh': 'radian',
-                   'degrees': 'degree', 'radians': 'radian',
+                   'arccos': __radian, 'arcsin': __radian,
+                   'arctan': __radian, 'arctan2': __radian,
+                   'arccosh': __radian, 'arcsinh': __radian,
+                   'arctanh': __radian,
+                   'degrees': 'degree', 'radians': __radian,
                    'expm1': '', 'cumprod': '',
-                   'rad2deg': 'degree', 'deg2rad': 'radian'}
+                   'rad2deg': 'degree', 'deg2rad': __radian}
 
     #: List of ufunc/attributes names in which units are copied from the
     #: original.
@@ -575,7 +575,9 @@ class _Quantity(object):
         ufname = uf.__name__ if huh == 0 else '{}__{}'.format(uf.__name__, huh)
         if uf.__name__ in self.__handled and huh == 0:
             if self.__handling:
-                raise Exception('Cannot handled nested ufuncs.\nCurrent: {}\nNew: {}'.format(context, self.__handling))
+                raise Exception('Cannot handled nested ufuncs.\n'
+                                'Current: {}\n'
+                                'New: {}'.format(context, self.__handling))
             self.__handling = context
 
         return obj
@@ -591,23 +593,35 @@ class _Quantity(object):
 
             if huh == 0:
                 dst_units = None
+                mobjs = None
                 if uf.__name__ in self.__require_units:
                     dst_units = self.__require_units[uf.__name__]
-                    if self.unitless and dst_units == 'radian':
-                        dst_units = None
+                    if dst_units == 'radian':
+                        mobjs = []
+                        for other in objs:
+                            unt = getattr(other, 'units', '')
+                            if unt == 'radian':
+                                mobjs.append(getattr(other, 'magnitude', other))
+                            else:
+                                factor, units = self._REGISTRY.get_base_units(unt)
+                                if units and units != UnitsContainer({'radian': 1}):
+                                    raise DimensionalityError(units, dst_units)
+                                mobjs.append(getattr(other, 'magnitude', other) * factor)
+                        mobjs = tuple(mobjs)
                     else:
                         dst_units = self._REGISTRY.parse_expression(dst_units).units
                 elif len(objs) > 1 and uf.__name__ not in self.__skip_other_args:
                     dst_units = objs[0].units
 
-                if dst_units is not None:
-                    mobjs = tuple(self._REGISTRY.convert(getattr(other, 'magnitude', other),
-                                                         getattr(other, 'units', ''),
-                                                         dst_units)
-                                  for other in objs)
-                else:
-                    mobjs = tuple(getattr(other, 'magnitude', other)
-                                  for other in objs)
+                if mobjs is None:
+                    if dst_units is not None:
+                        mobjs = tuple(self._REGISTRY.convert(getattr(other, 'magnitude', other),
+                                                             getattr(other, 'units', ''),
+                                                             dst_units)
+                                      for other in objs)
+                    else:
+                        mobjs = tuple(getattr(other, 'magnitude', other)
+                                      for other in objs)
 
                 out = uf(*mobjs)
 
diff --git a/pint/testsuite/test_issues.py b/pint/testsuite/test_issues.py
index add88c0..e1c54eb 100644
--- a/pint/testsuite/test_issues.py
+++ b/pint/testsuite/test_issues.py
@@ -93,3 +93,17 @@ class TestIssuesNP(TestCase):
         np.sqrt(x)
         self.assertAlmostEqual(np.sqrt([4.] * ureg.dimensionless), [2.] * ureg.dimensionless)
         self.assertAlmostEqual(np.sqrt(4. * ureg.dimensionless), 2. * ureg.dimensionless)
+
+    def test_issue45(self):
+        import math
+        ureg = UnitRegistry()
+        self.assertAlmostEqual(math.sqrt(4 * ureg.m/ureg.cm), math.sqrt(4 * 100))
+        self.assertAlmostEqual(float(ureg.V / ureg.mV), 1000.)
+
+    def test_issue45b(self):
+        ureg = UnitRegistry()
+        self.assertAlmostEqual(np.sin([np.pi/2] * ureg.m / ureg.m ), np.sin([np.pi/2] * ureg.dimensionless))
+        self.assertAlmostEqual(np.sin([np.pi/2] * ureg.cm / ureg.m ), np.sin([np.pi/2] * ureg.dimensionless * 0.01))
+
+
+
diff --git a/pint/testsuite/test_umath.py b/pint/testsuite/test_umath.py
index 041150c..db394ed 100644
--- a/pint/testsuite/test_umath.py
+++ b/pint/testsuite/test_umath.py
@@ -365,7 +365,7 @@ class TestTrigUfuncs(TestUFuncs):
         self._test1(np.sin, (np.arange(0, pi/2, pi/4) * self.ureg.dimensionless,
                              np.arange(0, pi/2, pi/4) * self.ureg.radian,
                              np.arange(0, pi/2, pi/4) * self.ureg.mm / self.ureg.m
-                            ), (self.ureg.m, ), '')
+                            ), (self.ureg.m, ), '', results=(None, None, np.sin(np.arange(0, pi/2, pi/4)*0.001)))
         self._test1(np.sin, (np.rad2deg(np.arange(0, pi/2, pi/4)) * self.ureg.degrees,
                             ), results=(np.sin(np.arange(0, pi/2, pi/4)), ))
 
@@ -373,7 +373,7 @@ class TestTrigUfuncs(TestUFuncs):
         self._test1(np.cos, (np.arange(0, pi/2, pi/4) * self.ureg.dimensionless,
                              np.arange(0, pi/2, pi/4) * self.ureg.radian,
                              np.arange(0, pi/2, pi/4) * self.ureg.mm / self.ureg.m
-                            ), (self.ureg.m, ), '')
+                            ), (self.ureg.m, ), '', results=(None, None, np.cos(np.arange(0, pi/2, pi/4)*0.001)))
         self._test1(np.cos, (np.rad2deg(np.arange(0, pi/2, pi/4)) * self.ureg.degrees,
                             ), results=(np.cos(np.arange(0, pi/2, pi/4)), ))
 
@@ -381,7 +381,7 @@ class TestTrigUfuncs(TestUFuncs):
         self._test1(np.tan, (np.arange(0, pi/2, pi/4) * self.ureg.dimensionless,
                              np.arange(0, pi/2, pi/4) * self.ureg.radian,
                              np.arange(0, pi/2, pi/4) * self.ureg.mm / self.ureg.m
-                            ), (self.ureg.m, ), '')
+                            ), (self.ureg.m, ), '', results=(None, None, np.tan(np.arange(0, pi/2, pi/4)*0.001)))
         self._test1(np.tan, (np.rad2deg(np.arange(0, pi/2, pi/4)) * self.ureg.degrees,
                             ), results=(np.tan(np.arange(0, pi/2, pi/4)), ))
 
@@ -421,7 +421,7 @@ class TestTrigUfuncs(TestUFuncs):
         self._test1(np.sinh, (np.arange(0, pi/2, pi/4) * self.ureg.dimensionless,
                               np.arange(0, pi/2, pi/4) * self.ureg.radian,
                               np.arange(0, pi/2, pi/4) * self.ureg.mm / self.ureg.m
-                              ), (self.ureg.m, ), '')
+                              ), (self.ureg.m, ), '', results=(None, None, np.sinh(np.arange(0, pi/2, pi/4)*0.001)))
         self._test1(np.sinh, (np.rad2deg(np.arange(0, pi/2, pi/4)) * self.ureg.degrees,
                               ), results=(np.sinh(np.arange(0, pi/2, pi/4)), ))
 
@@ -429,7 +429,7 @@ class TestTrigUfuncs(TestUFuncs):
         self._test1(np.cosh, (np.arange(0, pi/2, pi/4) * self.ureg.dimensionless,
                               np.arange(0, pi/2, pi/4) * self.ureg.radian,
                               np.arange(0, pi/2, pi/4) * self.ureg.mm / self.ureg.m
-                             ), (self.ureg.m, ), '')
+                             ), (self.ureg.m, ), '', results=(None, None, np.cosh(np.arange(0, pi/2, pi/4)*0.001)))
         self._test1(np.cosh, (np.rad2deg(np.arange(0, pi/2, pi/4)) * self.ureg.degrees,
                              ), results=(np.cosh(np.arange(0, pi/2, pi/4)), ))
 
@@ -437,7 +437,7 @@ class TestTrigUfuncs(TestUFuncs):
         self._test1(np.tanh, (np.arange(0, pi/2, pi/4) * self.ureg.dimensionless,
                               np.arange(0, pi/2, pi/4) * self.ureg.radian,
                               np.arange(0, pi/2, pi/4) * self.ureg.mm / self.ureg.m
-                             ), (self.ureg.m, ), '')
+                             ), (self.ureg.m, ), '', results=(None, None, np.tanh(np.arange(0, pi/2, pi/4)*0.001)))
         self._test1(np.tanh, (np.rad2deg(np.arange(0, pi/2, pi/4)) * self.ureg.degrees,
                              ), results=(np.tanh(np.arange(0, pi/2, pi/4)), ))
 
@@ -464,7 +464,8 @@ class TestTrigUfuncs(TestUFuncs):
         self._test1(np.rad2deg, (np.arange(0, pi/2, pi/4) * self.ureg.dimensionless,
                                  np.arange(0, pi/2, pi/4) * self.ureg.radian,
                                  np.arange(0, pi/2, pi/4) * self.ureg.mm / self.ureg.m
-                                 ), (self.ureg.m, ), 'degree')
+                                 ), (self.ureg.m, ), 'degree', results=(None, None, np.rad2deg(np.arange(0, pi/2, pi/4)*0.001)))
+
 
 
 class TestComparisonUfuncs(TestUFuncs):