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octavemagic.py
382 lines | 10.4 KiB | text/x-python | PythonLexer
# -*- coding: utf-8 -*-
"""
===========
octavemagic
===========
Magics for interacting with Octave via oct2py.
.. note::
The ``oct2py`` module needs to be installed separately and
can be obtained using ``easy_install`` or ``pip``.
You will also need a working copy of GNU Octave.
Usage
=====
To enable the magics below, execute ``%load_ext octavemagic``.
``%octave``
{OCTAVE_DOC}
``%octave_push``
{OCTAVE_PUSH_DOC}
``%octave_pull``
{OCTAVE_PULL_DOC}
"""
#-----------------------------------------------------------------------------
# Copyright (C) 2012 The IPython Development Team
#
# Distributed under the terms of the BSD License. The full license is in
# the file COPYING, distributed as part of this software.
#-----------------------------------------------------------------------------
import tempfile
from glob import glob
from shutil import rmtree
import sys
import numpy as np
import oct2py
from xml.dom import minidom
from IPython.core.displaypub import publish_display_data
from IPython.core.magic import (Magics, magics_class, line_magic,
line_cell_magic, needs_local_scope)
from IPython.testing.skipdoctest import skip_doctest
from IPython.core.magic_arguments import (
argument, magic_arguments, parse_argstring
)
from IPython.utils.py3compat import unicode_to_str
from IPython.utils.text import dedent
class OctaveMagicError(oct2py.Oct2PyError):
pass
_mimetypes = {'png' : 'image/png',
'svg' : 'image/svg+xml',
'jpg' : 'image/jpeg',
'jpeg': 'image/jpeg'}
@magics_class
class OctaveMagics(Magics):
"""A set of magics useful for interactive work with Octave via oct2py.
"""
def __init__(self, shell):
"""
Parameters
----------
shell : IPython shell
"""
super(OctaveMagics, self).__init__(shell)
self._oct = oct2py.Oct2Py()
if sys.platform == 'win32':
# Use svg by default due to lack of Ghostscript on Windows Octave
self._plot_format = 'svg'
else:
self._plot_format = 'png'
# Allow publish_display_data to be overridden for
# testing purposes.
self._publish_display_data = publish_display_data
def _fix_gnuplot_svg_size(self, image, size=None):
"""
GnuPlot SVGs do not have height/width attributes. Set
these to be the same as the viewBox, so that the browser
scales the image correctly.
Parameters
----------
image : str
SVG data.
size : tuple of int
Image width, height.
"""
(svg,) = minidom.parseString(image).getElementsByTagName('svg')
viewbox = svg.getAttribute('viewBox').split(' ')
if size is not None:
width, height = size
else:
width, height = viewbox[2:]
svg.setAttribute('width', '%dpx' % width)
svg.setAttribute('height', '%dpx' % height)
return svg.toxml()
@skip_doctest
@line_magic
def octave_push(self, line):
'''
Line-level magic that pushes a variable to Octave.
`line` should be made up of whitespace separated variable names in the
IPython namespace::
In [7]: import numpy as np
In [8]: X = np.arange(5)
In [9]: X.mean()
Out[9]: 2.0
In [10]: %octave_push X
In [11]: %octave mean(X)
Out[11]: 2.0
'''
inputs = line.split(' ')
for input in inputs:
input = unicode_to_str(input)
self._oct.put(input, self.shell.user_ns[input])
@skip_doctest
@line_magic
def octave_pull(self, line):
'''
Line-level magic that pulls a variable from Octave.
::
In [18]: _ = %octave x = [1 2; 3 4]; y = 'hello'
In [19]: %octave_pull x y
In [20]: x
Out[20]:
array([[ 1., 2.],
[ 3., 4.]])
In [21]: y
Out[21]: 'hello'
'''
outputs = line.split(' ')
for output in outputs:
output = unicode_to_str(output)
self.shell.push({output: self._oct.get(output)})
@skip_doctest
@magic_arguments()
@argument(
'-i', '--input', action='append',
help='Names of input variables to be pushed to Octave. Multiple names '
'can be passed, separated by commas with no whitespace.'
)
@argument(
'-o', '--output', action='append',
help='Names of variables to be pulled from Octave after executing cell '
'body. Multiple names can be passed, separated by commas with no '
'whitespace.'
)
@argument(
'-s', '--size', action='store',
help='Pixel size of plots, "width,height". Default is "-s 400,250".'
)
@argument(
'-f', '--format', action='store',
help='Plot format (png, svg or jpg).'
)
@needs_local_scope
@argument(
'code',
nargs='*',
)
@line_cell_magic
def octave(self, line, cell=None, local_ns=None):
'''
Execute code in Octave, and pull some of the results back into the
Python namespace::
In [9]: %octave X = [1 2; 3 4]; mean(X)
Out[9]: array([[ 2., 3.]])
As a cell, this will run a block of Octave code, without returning any
value::
In [10]: %%octave
....: p = [-2, -1, 0, 1, 2]
....: polyout(p, 'x')
-2*x^4 - 1*x^3 + 0*x^2 + 1*x^1 + 2
In the notebook, plots are published as the output of the cell, e.g.::
%octave plot([1 2 3], [4 5 6])
will create a line plot.
Objects can be passed back and forth between Octave and IPython via the
-i and -o flags in line::
In [14]: Z = np.array([1, 4, 5, 10])
In [15]: %octave -i Z mean(Z)
Out[15]: array([ 5.])
In [16]: %octave -o W W = Z * mean(Z)
Out[16]: array([ 5., 20., 25., 50.])
In [17]: W
Out[17]: array([ 5., 20., 25., 50.])
The size and format of output plots can be specified::
In [18]: %%octave -s 600,800 -f svg
...: plot([1, 2, 3]);
'''
args = parse_argstring(self.octave, line)
# arguments 'code' in line are prepended to the cell lines
if cell is None:
code = ''
return_output = True
else:
code = cell
return_output = False
code = ' '.join(args.code) + code
# if there is no local namespace then default to an empty dict
if local_ns is None:
local_ns = {}
if args.input:
for input in ','.join(args.input).split(','):
input = unicode_to_str(input)
try:
val = local_ns[input]
except KeyError:
val = self.shell.user_ns[input]
self._oct.put(input, val)
# generate plots in a temporary directory
plot_dir = tempfile.mkdtemp().replace('\\', '/')
if args.size is not None:
size = args.size
else:
size = '400,240'
if args.format is not None:
plot_format = args.format
elif sys.platform == 'win32':
# Use svg by default due to lack of Ghostscript on Windows Octave
plot_format = 'svg'
else:
plot_format = 'png'
pre_call = '''
global __ipy_figures = [];
page_screen_output(0);
function fig_create(src, event)
global __ipy_figures;
__ipy_figures(size(__ipy_figures) + 1) = src;
set(src, "visible", "off");
end
set(0, 'DefaultFigureCreateFcn', @fig_create);
close all;
clear ans;
# ___<end_pre_call>___ #
'''
post_call = '''
# ___<start_post_call>___ #
# Save output of the last execution
if exist("ans") == 1
_ = ans;
else
_ = nan;
end
for f = __ipy_figures
outfile = sprintf('%(plot_dir)s/__ipy_oct_fig_%%03d.png', f);
try
print(f, outfile, '-d%(plot_format)s', '-tight', '-S%(size)s');
end
end
''' % locals()
code = ' '.join((pre_call, code, post_call))
try:
text_output = self._oct.run(code, verbose=False)
except (oct2py.Oct2PyError) as exception:
msg = exception.message
msg = msg.split('# ___<end_pre_call>___ #')[1]
msg = msg.split('# ___<start_post_call>___ #')[0]
raise OctaveMagicError('Octave could not complete execution. '
'Traceback (currently broken in oct2py): %s'
% msg)
key = 'OctaveMagic.Octave'
display_data = []
# Publish text output
if text_output:
display_data.append((key, {'text/plain': text_output}))
# Publish images
images = [open(imgfile, 'rb').read() for imgfile in \
glob("%s/*" % plot_dir)]
rmtree(plot_dir)
plot_mime_type = _mimetypes.get(plot_format, 'image/png')
width, height = [int(s) for s in size.split(',')]
for image in images:
if plot_format == 'svg':
image = self._fix_gnuplot_svg_size(image, size=(width, height))
display_data.append((key, {plot_mime_type: image}))
if args.output:
for output in ','.join(args.output).split(','):
output = unicode_to_str(output)
self.shell.push({output: self._oct.get(output)})
for source, data in display_data:
self._publish_display_data(source, data)
if return_output:
ans = self._oct.get('_')
# Unfortunately, Octave doesn't have a "None" object,
# so we can't return any NaN outputs
if np.isscalar(ans) and np.isnan(ans):
ans = None
return ans
__doc__ = __doc__.format(
OCTAVE_DOC = dedent(OctaveMagics.octave.__doc__),
OCTAVE_PUSH_DOC = dedent(OctaveMagics.octave_push.__doc__),
OCTAVE_PULL_DOC = dedent(OctaveMagics.octave_pull.__doc__)
)
def load_ipython_extension(ip):
"""Load the extension in IPython."""
ip.register_magics(OctaveMagics)