slow.nansum and slow.ss now longer coerce dtype

closes pydata#180

RELEASE.rst

@@ -13,6 +13,8 @@ Bottleneck 1.3.0
 
 - Move documentation to https://kwgoodman.github.io/bottleneck-doc
 - Remove numpydoc package from Bottleneck source distribution
+- bn.slow.nansum and bn.slow.ss now longer coerce output to have the same
+  dtype as input
 
 **Bug Fixes**
 

bottleneck/slow/reduce.py

@@ -1,21 +1,12 @@
 import warnings
 import numpy as np
-from numpy import nanmean
+from numpy import nanmean, nansum
 
 __all__ = ['median', 'nanmedian', 'nansum', 'nanmean', 'nanvar', 'nanstd',
            'nanmin', 'nanmax', 'nanargmin', 'nanargmax', 'ss', 'anynan',
            'allnan']
 
 
-def nansum(a, axis=None):
-    "Slow nansum function used for unaccelerated dtype."
-    a = np.asarray(a)
-    y = np.nansum(a, axis=axis)
-    if y.dtype != a.dtype:
-        y = y.astype(a.dtype)
-    return y
-
-
 def nanargmin(a, axis=None):
     "Slow nanargmin function used for unaccelerated dtypes."
     with warnings.catch_warnings():
@@ -76,8 +67,6 @@ def ss(a, axis=None):
     "Slow sum of squares used for unaccelerated dtypes."
     a = np.asarray(a)
     y = np.multiply(a, a).sum(axis)
-    if y.dtype != a.dtype:
-        y = y.astype(a.dtype)
     return y
 
 

bottleneck/tests/reduce_test.py

@@ -19,7 +19,7 @@ def test_reduce():
         yield unit_maker, func
 
 
-def unit_maker(func, decimal=5):
+def unit_maker(func, decimal=5, skip_dtype=['nansum', 'ss']):
     "Test that bn.xxx gives the same output as bn.slow.xxx."
     fmt = '\nfunc %s | input %s (%s) | shape %s | axis %s | order %s\n'
     fmt += '\nInput array:\n%s\n'
@@ -62,10 +62,11 @@ def unit_maker(func, decimal=5):
                     ok_(False, err_msg)
                 assert_array_almost_equal(actual, desired, decimal, err_msg)
                 err_msg += '\n dtype mismatch %s %s'
-                if hasattr(actual, 'dtype') and hasattr(desired, 'dtype'):
-                    da = actual.dtype
-                    dd = desired.dtype
-                    assert_equal(da, dd, err_msg % (da, dd))
+                if name not in skip_dtype:
+                    if hasattr(actual, 'dtype') and hasattr(desired, 'dtype'):
+                        da = actual.dtype
+                        dd = desired.dtype
+                        assert_equal(da, dd, err_msg % (da, dd))
 
 
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