Merge from documentation editor.

1 files changed, 71 insertions, 6 deletions

diff --git a/numpy/lib/ufunclike.py b/numpy/lib/ufunclike.py
index a8c2c1e25..37c38e94e 100644
--- a/numpy/lib/ufunclike.py
+++ b/numpy/lib/ufunclike.py
@@ -24,9 +24,30 @@ def fix(x, y=None):
     return y
 
 def isposinf(x, y=None):
-    """Return a boolean array y with y[i] True for x[i] = +Inf.
+    """
+    Return True where x is +infinity, and False otherwise.
+
+    Parameters
+    ----------
+    x : array_like
+      The input array.
+    y : array_like
+      A boolean array with the same shape as `x` to store the result.
+
+    Returns
+    -------
+    y : ndarray
+      A boolean array where y[i] = True only if x[i] = +Inf.
+
+    See Also
+    --------
+    isneginf, isfinite
+
+    Examples
+    --------
+    >>> np.isposinf([-np.inf, 0., np.inf])
+    array([ False, False, True], dtype=bool)
 
-    If y is an array, the result replaces the contents of y.
     """
     if y is None:
         x = asarray(x)
@@ -35,9 +56,30 @@ def isposinf(x, y=None):
     return y
 
 def isneginf(x, y=None):
-    """Return a boolean array y with y[i] True for x[i] = -Inf.
+    """
+    Return True where x is -infinity, and False otherwise.
+
+    Parameters
+    ----------
+    x : array_like
+      The input array.
+    y : array_like
+      A boolean array with the same shape as `x` to store the result.
+
+    Returns
+    -------
+    y : ndarray
+      A boolean array where y[i] = True only if x[i] = -Inf.
+
+    See Also
+    --------
+    isposinf, isfinite
+
+    Examples
+    --------
+    >>> np.isneginf([-np.inf, 0., np.inf])
+    array([ True, False, False], dtype=bool)
 
-    If y is an array, the result replaces the contents of y.
     """
     if y is None:
         x = asarray(x)
@@ -47,9 +89,32 @@ def isneginf(x, y=None):
 
 _log2 = umath.log(2)
 def log2(x, y=None):
-    """Returns the base 2 logarithm of x
+    """
+    Return the base 2 logarithm.
+
+    Parameters
+    ----------
+    x : array_like
+      Input array.
+    y : array_like
+      Optional output array with the same shape as `x`.
+
+    Returns
+    -------
+    y : {ndarray, scalar}
+      The logarithm to the base 2 of `x` elementwise.
+      NaNs are returned where `x` is negative.
+
+
+    See Also
+    --------
+    log, log1p, log10
+
+    Examples
+    --------
+    >>> np.log2([-1,2,4])
+    array([ NaN,   1.,   2.])
 
-    If y is an array, the result replaces the contents of y.
     """
     x = asanyarray(x)
     if y is None: