## Using JNumeric with Jython scripting

Useful hints
tomw
Posts: 296
Joined: Tue Dec 23, 2008 3:40 pm

### Using JNumeric with Jython scripting

A port of the Python "Numeric" class was done some time ago and dubbed "JNumeric". This library is included with McIDAS-V and provides for more "natural" expressions of (mostly) array manipulations -- much like what you can do with VisAD "Data" objects (simple arithmetic expressions that operate on an entire array, for example).

To use this library with your Jython scripting, you just need to "import Numeric". You might find it convenient to makes sure there are no name conflicts by using something like this:

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``import Numeric as N``

You can then do things like:

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``a=N.array([1,2,3])b=N.array([3,2,1])print a,b[1 2 3] [3 2 1] print N.greater(a,b)[0 0 1] print N.sin(a)[0.841470984808 0.909297426826 0.14112000806] c = a*bprint c[3 4 3]``

More complete documentation of the available methods along with lots of examples can be found at sites like:
http://gfesuite.noaa.gov/AWIPS/ob7.2a/doc/onlinehelp/numdoc.html
Although this applies to the newer NumPy package, so some methods there will not be applicable.

Here is a listing of what is in JNumeric, though:

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``['ArrayType', 'Complex', 'Complex128', 'Complex64', 'FFT', 'Float', 'Float32', 'Float64', 'Int', 'Int16', 'Int32', 'Int64', 'Int8', 'LittleEndian', 'NewAxis', , 'add', 'alltrue', 'arange', 'arccos', 'arccosh', 'arcsin', 'arcsinh', 'arctan', 'arctanh', 'argmax', 'argmin', 'argsort', 'array', 'arrayrange', 'asarray', 'bitwise_and', 'bitwise_not', 'bitwise_or', 'bitwise_xor', 'ceil', 'choose', 'classDictInit', 'clip', 'compress', 'concatenate', 'conjugate', 'convolve', 'cos', 'cosh', 'cross_correlate', 'cumproduct', 'cumsum', 'diagonal', 'divide', 'dot', 'e', 'equal', 'exp', 'floor', 'fromfunction', 'fromstring', 'greater', 'greater_equal', 'identity', 'imaginary', 'indices', 'innerproduct', 'less', 'less_equal', 'log', 'log10', 'logical_and', 'logical_not', 'logical_or', 'logical_xor', 'maximum', 'minimum', 'multiply', 'nonzero', 'not_equal', 'ones', 'pi', 'power', 'product', 'ravel', 'real', 'remainder', 'repeat', 'reshape', 'resize', 'searchsorted', 'shape', 'sin', 'sinh', 'sometrue', 'sort', 'sqrt', 'subtract', 'sum', 'take', 'tan', 'tanh', 'trace', 'transpose', 'umath', 'where', 'zeros'] ``