[Numpy-discussion] matlab vs. python question
Simon Berube
sberub at gmail.com
Fri Apr 27 16:46:02 EDT 2007
Actually, all the points in this thread have been very good points but
I just want to add my 2 cents since I was in your boat just a month
ago and decided to try out python after seeing what it could do.
In short, I decided to look elsewhere as I was dealing with vector
data in database and maintaining so many different function and files
was getting hard and while Matlab has classes they are very unwieldy
to use and it is such an oddity in matlab that using them would
confuse whoever uses your code anyway. At least in my experience.
However after playing with Python, matplotlib and numpy I have found
that the code is much cleaner, the language is much more powerful and
clean, matplotlib is extremely capable for 2D plotting and iPython
integrates all those things very well.
The only thing I miss about matlab are the help tool which is quite
frankly the best I have seen, the many different toolboxes, the
compatibility with most hardware DAC and just the fact damn near
everyone in the scientific community uses either Matlab or plain
Fortran/C/C++.
However, I would disagree that Python with all its tools going to
replace Matlab well for everything. For large projects, for advanced
programmers and for non-standard things such as complex database
handling (in my case) it is definitly a clear winner. However, I would
be weary of getting Matlab completely out of the picture because I
find it is still a much better tool for algorithm testing, scripting
and other "use for a week" functions .
Hope this helps a bit too.
On Apr 27, 1:23 am, belinda thom <b... at cs.hmc.edu> wrote:
> Thank you so much! When I finally get a moment to take a break, I'll
> look in more detail into using your suggestion.
>
> --b
>
> On Apr 26, 2007, at 12:47 AM, Pauli Virtanen wrote:
>
>
>
> > belinda thom kirjoitti:
> >> On Apr 25, 2007, at 12:46 PM, Bill Baxter wrote:
>
> >> Agree w/most of what you've said, but will add one other thing that
> >> drives me nuts in python that hasn't been a problem in Matplotlib:
>
> >> In Python, if interacting w/the interpreter as your primary IDE, and
> >> if you've got multiple files that depend on one another that you're
> >> modifying, then you need to restart the interpreter frequently b/c
> >> otherwise things in the interpreter can be stale; IOW, changes to
> >> several interdependent files aren't easy to import so that everything
> >> in your interpreted environment reflects the latest code. Yeah,
> >> there's reload tricks, but doing them in the right order and the
> >> right number of times can be a pain when dependencies are cyclic.
>
> >> I realize in general that this issue of stale code is just difficult,
> >> that its not inherently a Python problem per se, for automatic
> >> percolation of code changes backwards in time is difficult in
> >> general, but I've never had the problem bite me when I was developing
> >> in Matlab. I just save whatever file, and it appears that whatever's
> >> latest on disk is what's executed. (Friends who know more about PL
> >> than I tell me I've been lucky.)
>
> > I've been using the attached autoreload code (by Thomas Heller,
> > different versions are probably floating around the net) rather
> > successfully for a more Matlabish feel to IPython. It reloads modules
> > every time their files have been changed.
>
> > Of course, this doesn't solve all staleness problems you describe, but
> > only eliminates manual work involved in solving the most common ones.
> > Reloading modules does have pitfalls [1], but at least in my use these
> > haven't really mattered much in practice.
>
> > I think having autoreload functionality bundled with IPython (maybe
> > turned off per default) would be quite useful: although in some rare
> > cases autoreloading doesn't work in the ideal way, it's very
> > convenient
> > not to have to type reload(foo) after every change, especially when
> > tweaking for example plotting scripts.
>
> > Pauli
>
> > [1] For example, instances of classes created are not updated on
> > reload,
> > but continue using the old code. Also, from foo import * imports
> > are not
> > updated, so you'll have to manually touch files that do this if 'foo'
> > has been changed.
> > """
>
> > autoreload.py - automatically reload changed source
> > code into a running program
>
> > You might want to add the following to your ~/.ipython/ipythonrc
>
> > import_mod sys
> > execute sys.path.append('path/where/this/file/resides')
> > import_mod autoreload
> > execute autoreload.run()
>
> > or adding the following
>
> > import sys
> > sys.path.append('path/where/this/file/resides')
> > import autoreload
> > autoreload.run()
>
> > to some startup file.
>
> > Created: Thomas Heller, 2000-04-17
> > Modified: Pauli Virtanen, 2006
> > """
>
> > # $Id: autoreload.py 3117 2006-09-27 20:28:46Z pauli $
> > #
> > # $Log: autoreload.py,v $
> > # Revision 1.9 2001/11/15 18:41:18 thomas
> > # Cleaned up and made working again before posting to c.l.p.
> > # Added code to update bound (or unbound) methods as suggested
> > # by Just van Rossum. Thanks!
> > #
> > # ...
> > #
> > # Revision 1.1 2001/10/04 16:54:04 thomas
> > # Discovered this old module on my machine, it didn't work too well,
> > # but seems worth to continue with it...
> > # Checked in as a first step.
>
> > __version__ = "$Revision: 1.9 $".split()[1]
>
> > # ToDo:
> > #
> > # Cannot reload __main__ - explain why this cannot work,
> > # and explain a workaround.
> > #
> > # Optimize - the number of watches objects (in old_objects)
> > # grows without limits. Think if this is really necessary...
>
> > import time, os, threading, sys, types, imp, inspect, traceback
>
> > def _get_compiled_ext():
> > for ext, mode, typ in imp.get_suffixes():
> > if typ == imp.PY_COMPILED:
> > return ext
>
> > # the official way to get the extension of compiled files (.pyc
> > or .pyo)
> > PY_COMPILED_EXT = _get_compiled_ext()
>
> > class ModuleWatcher:
> > running = 0
> > def __init__(self):
> > # If we don't do this, there may be tracebacks
> > # when shutting down python.
> > import atexit
> > atexit.register(self.stop)
>
> > def run(self):
> > if self.running:
> > print "# autoreload already running"
> > return
> > print "# starting autoreload"
> > self.running = 1
> > self.thread = threading.Thread(target=self._check_modules)
> > self.thread.setDaemon(1)
> > self.thread.start()
>
> > def stop(self):
> > if not self.running:
> > print "# autoreload not running"
> > return
> > self.running = 0
> > self.thread.join()
> > #print "# autoreload stopped"
>
> > def _check_modules(self):
> > skipped = {}
> > while self.running:
> > time.sleep(0.01)
> > for m in sys.modules.values():
> > if not hasattr(m, '__file__'):
> > continue
> > if m.__name__ == '__main__':
>
> > # we cannot reload(__main__) First I thought we
> > # could use mod = imp.load_module() and then
> > # reload(mod) to simulate reload(main), but this
> > # would execute the code in __main__ a second
> > # time.
>
> > continue
> > file = m.__file__
> > dirname = os.path.dirname(file)
> > path, ext = os.path.splitext(file)
>
> > if ext.lower() == '.py':
> > ext = PY_COMPILED_EXT
> > file = os.path.join(dirname, path +
> > PY_COMPILED_EXT)
>
> > if ext != PY_COMPILED_EXT:
> > continue
>
> > try:
> > pymtime = os.stat(file[:-1])[8]
> > if pymtime <= os.stat(file)[8]:
> > continue
> > if skipped.get(file[:-1], None) == pymtime:
> > continue
> > except OSError:
> > continue
>
> > try:
> > superreload(m)
> > if file[:-1] in skipped:
> > del skipped[file[:-1]]
> > except:
> > skipped[file[:-1]] = pymtime
> > import traceback
> > traceback.print_exc(0)
>
> > def update_function(old, new, attrnames):
> > for name in attrnames:
> > setattr(old, name, getattr(new, name))
>
> > def superreload(module,
> > reload=reload,
> > _old_objects = {}):
> > """superreload (module) -> module
>
> > Enhanced version of the builtin reload function.
> > superreload replaces the class dictionary of every top-level
> > class in the module with the new one automatically,
> > as well as every function's code object.
> > """
> > ## start = time.clock()
> > # retrieve the attributes from the module before the reload,
> > # and remember them in _old_objects.
> > for name, object in module.__dict__.items():
> > key = (module.__name__, name)
> > _old_objects.setdefault(key, []).append(object)
> > # print the refcount of old objects:
> > ## if type(object) in (types.FunctionType, types.ClassType):
> > ## print name, map(sys.getrefcount, _old_objects[key])
>
> > ## print "# reloading module %r" % module
>
> > module = reload(module)
> > # XXX We have a problem here if importing the module fails!
>
> > # iterate over all objects and update them
> > count = 0
> > # XXX Can we optimize here?
> > # It may be that no references to the objects are present
> > # except those from our _old_objects dictionary.
> > # We should remove those. I have to learn about weak-refs!
> > for name, new_obj in module.__dict__.items():
> > key = (module.__name__, name)
> > if _old_objects.has_key(key):
> > for old_obj in _old_objects[key]:
> > if type(new_obj) == types.ClassType:
> > old_obj.__dict__.update(new_obj.__dict__)
> > count += 1
> > elif type(new_obj) == types.FunctionType:
> > update_function(old_obj,
> > new_obj,
> > "func_code func_defaults func_doc".split())
> > count += 1
> > elif type(new_obj) == types.MethodType:
> > update_function(old_obj.im_func,
> > new_obj.im_func,
> > "func_code func_defaults func_doc".split())
> > count += 1
> > ## stop = time.clock()
> > ## print "# updated %d objects from %s" % (count, module)
> > ## print "# This took %.3f seconds" % (stop - start)
>
> > return module
>
> > _watcher = ModuleWatcher()
>
> > run = _watcher.run
> > stop = _watcher.stop
>
> > __all__ = ['run', 'stop', 'superreload']
> > _______________________________________________
> > Numpy-discussion mailing list
> > Numpy-discuss... at scipy.org
> >http://projects.scipy.org/mailman/listinfo/numpy-discussion
>
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