Merge pull request #186 from rsokl/numpy-vectorized

call out numpy overrides math operators

Author: rsokl

Python/Module3_IntroducingNumpy/VectorizedOperations.md

@@ -283,6 +283,14 @@ The "modulo" function ("mod" for short), denoted by $\%$, is defined to return t
 
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+**Using Math Operators on NumPy Arrays**: 
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+It is important to note that NumPy arrays know how to "override" the standard mathematical operators so that they invoke vectorized functions. For example, suppose `arr1` and `arr2` are NumPy arrays; calling `arr1 + arr2` ends up calling `np.add(arr1, arr2)` "under the hood". Thus we can safely use the standard math operators `+ - / * **` between NumPy arrays, and fast vectorized functions will be used for us. 
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 As indicated in this table, these NumPy functions can be called by invoking the familiar Python math-operators, when used in the context of NumPy arrays.
 
 Here are some other common binary functions: