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authorCharles Harris <charlesr.harris@gmail.com>2006-09-04 17:06:31 +0000
committerCharles Harris <charlesr.harris@gmail.com>2006-09-04 17:06:31 +0000
commitcd71708a570b7eb770e54ba08ccbf7b414b26201 (patch)
tree32d3c4899f857f4be3dbd51b5037a16f3dd60dae /numpy/add_newdocs.py
parent2d72b34fb356c1f5440218123c06efd534555303 (diff)
downloadnumpy-cd71708a570b7eb770e54ba08ccbf7b414b26201.tar.gz
Add documentation to round and around to clear up confusion from numpy's choice
to round to even.
Diffstat (limited to 'numpy/add_newdocs.py')
-rw-r--r--numpy/add_newdocs.py23
1 files changed, 22 insertions, 1 deletions
diff --git a/numpy/add_newdocs.py b/numpy/add_newdocs.py
index 86773335b..3b130c63b 100644
--- a/numpy/add_newdocs.py
+++ b/numpy/add_newdocs.py
@@ -848,7 +848,28 @@ add_newdoc('numpy.core.multiarray', 'ndarray', ('resize',
add_newdoc('numpy.core.multiarray', 'ndarray', ('round',
- """a.round(decimals=0, out=None)
+ """a.round(decimals=0, out=None) -> out (a). Rounds to 'decimals' places.
+
+ Keyword arguments:
+ decimals -- number of decimals to round to (default 0). May be negative.
+ out -- existing array to use for output (default a).
+
+ Return:
+ Reference to out, where None specifies the original array a.
+
+ Round to the specified number of decimals. When 'decimals' is negative it
+ specifies the number of positions to the left of the decimal point. The real
+ and imaginary parts of complex numbers are rounded separately. Nothing is
+ done if the array is not of float type.
+
+ The keyword 'out' may be used to specify a different array to hold the
+ result rather than the default 'a'. If the type of the array specified by
+ 'out' differs from that of 'a', the result is cast to the new type.
+
+ Numpy rounds to even. Thus 1.5 and 2.5 round to 2, -0.5 and 0.5 round to 0,
+ etc. Results may also be surprising due to the inexact representation of
+ decimal fractions in IEEE floating point and the errors introduced in
+ scaling the numbers when 'decimals' is something other than 0.
"""))