#! /usr/bin/env python
# $Id: utils.py 297 2007-03-30 11:25:28Z mhagger $
# Copyright (C) 1998-2003 Michael Haggerty <mhagger@alum.mit.edu>
#
# This file is licensed under the GNU Lesser General Public License
# (LGPL). See LICENSE.txt for details.
"""utils.py -- Utility functions used by Gnuplot.
This module contains utility functions used by Gnuplot.py which aren't
particularly gnuplot-related.
"""
import string
import numpy
def float_array(m):
"""Return the argument as a numpy array of type at least 'Float32'.
Leave 'Float64' unchanged, but upcast all other types to
'Float32'. Allow also for the possibility that the argument is a
python native type that can be converted to a numpy array using
'numpy.asarray()', but in that case don't worry about
downcasting to single-precision float.
"""
try:
# Try Float32 (this will refuse to downcast)
return numpy.asarray(m, numpy.float32)
except TypeError:
# That failure might have been because the input array was
# of a wider data type than float32; try to convert to the
# largest floating-point type available:
# NOTE TBD: I'm not sure float_ is the best data-type for this...
try:
return numpy.asarray(m, numpy.float_)
except TypeError:
# TBD: Need better handling of this error!
print "Fatal: array dimensions not equal!"
return None
def write_array(f, set,
item_sep=' ',
nest_prefix='', nest_suffix='\n', nest_sep=''):
"""Write an array of arbitrary dimension to a file.
A general recursive array writer. The last four parameters allow
a great deal of freedom in choosing the output format of the
array. The defaults for those parameters give output that is
gnuplot-readable. But using '(",", "{", "}", ",\n")' would output
an array in a format that Mathematica could read. 'item_sep'
should not contain '%' (or if it does, it should be escaped to
'%%') since it is put into a format string.
The default 2-d file organization::
set[0,0] set[0,1] ...
set[1,0] set[1,1] ...
The 3-d format::
set[0,0,0] set[0,0,1] ...
set[0,1,0] set[0,1,1] ...
set[1,0,0] set[1,0,1] ...
set[1,1,0] set[1,1,1] ...
"""
if len(set.shape) == 1:
(columns,) = set.shape
assert columns > 0
fmt = string.join(['%s'] * columns, item_sep)
f.write(nest_prefix)
f.write(fmt % tuple(set.tolist()))
f.write(nest_suffix)
elif len(set.shape) == 2:
# This case could be done with recursion, but `unroll' for
# efficiency.
(points, columns) = set.shape
assert points > 0 and columns > 0
fmt = string.join(['%s'] * columns, item_sep)
f.write(nest_prefix + nest_prefix)
f.write(fmt % tuple(set[0].tolist()))
f.write(nest_suffix)
for point in set[1:]:
f.write(nest_sep + nest_prefix)
f.write(fmt % tuple(point.tolist()))
f.write(nest_suffix)
f.write(nest_suffix)
else:
# Use recursion for three or more dimensions:
assert set.shape[0] > 0
f.write(nest_prefix)
write_array(f, set[0],
item_sep, nest_prefix, nest_suffix, nest_sep)
for subset in set[1:]:
f.write(nest_sep)
write_array(f, subset,
item_sep, nest_prefix, nest_suffix, nest_sep)
f.write(nest_suffix)
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