1 files changed, 86 insertions, 0 deletions
diff --git a/numpy/lib/scimath.py b/numpy/lib/scimath.py
new file mode 100644
index 000000000..c15f254a3
--- /dev/null
+++ b/numpy/lib/scimath.py
@@ -0,0 +1,86 @@
+"""
+Wrapper functions to more user-friendly calling of certain math functions
+whose output data-type is different than the input data-type in certain
+domains of the input.
+"""
+
+__all__ = ['sqrt', 'log', 'log2', 'logn','log10', 'power', 'arccos',
+           'arcsin', 'arctanh']
+
+import numpy.core.numeric as nx
+import numpy.core.numerictypes as nt
+from numpy.core.numeric import asarray, any
+from numpy.lib.type_check import isreal
+
+
+#__all__.extend([key for key in dir(nx.umath)
+#                if key[0] != '_' and key not in __all__])
+
+_ln2 = nx.log(2.0)
+
+def _tocomplex(arr):
+    if isinstance(arr.dtype, (nt.single, nt.byte, nt.short, nt.ubyte,
+                              nt.ushort)):
+        return arr.astype(nt.csingle)
+    else:
+        return arr.astype(nt.cdouble)
+
+def _fix_real_lt_zero(x):
+    x = asarray(x)
+    if any(isreal(x) & (x<0)):
+        x = _tocomplex(x)
+    return x
+
+def _fix_int_lt_zero(x):
+    x = asarray(x)
+    if any(isreal(x) & (x < 0)):
+        x = x * 1.0
+    return x
+
+def _fix_real_abs_gt_1(x):
+    x = asarray(x)
+    if any(isreal(x) & (abs(x)>1)):
+        x = _tocomplex(x)
+    return x
+
+def sqrt(x):
+    x = _fix_real_lt_zero(x)
+    return nx.sqrt(x)
+
+def log(x):
+    x = _fix_real_lt_zero(x)
+    return nx.log(x)
+
+def log10(x):
+    x = _fix_real_lt_zero(x)
+    return nx.log10(x)
+
+def logn(n, x):
+    """ Take log base n of x.
+    """
+    x = _fix_real_lt_zero(x)
+    n = _fix_real_lt_zero(n)
+    return nx.log(x)/nx.log(n)
+
+def log2(x):
+    """ Take log base 2 of x.
+    """
+    x = _fix_real_lt_zero(x)
+    return nx.log(x)/_ln2
+
+def power(x, p):
+    x = _fix_real_lt_zero(x)
+    p = _fix_int_lt_zero(p)
+    return nx.power(x, p)
+
+def arccos(x):
+    x = _fix_real_abs_gt_1(x)
+    return nx.arccos(x)
+
+def arcsin(x):
+    x = _fix_real_abs_gt_1(x)
+    return nx.arcsin(x)
+
+def arctanh(x):
+    x = _fix_real_abs_gt_1(x)
+    return nx.arctanh(x)