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comparison doc/v2_planning/arch_src/plugin_JB.py @ 1212:478bb1f8215c

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plugin_JB - added SPAWN control element and demo program
author James Bergstra <bergstrj@iro.umontreal.ca>
date Wed, 22 Sep 2010 01:37:55 -0400
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children 9fac28d80fb7
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1211:e7ac87720fee 1212:478bb1f8215c
1 """plugin_JB - draft of potential library architecture using iterators
2
3 This strategy makes use of a simple imperative language whose statements are python function
4 calls to create learning algorithms that can be manipulated and executed in several desirable
5 ways.
6
7 The training procedure for a PCA module is easy to express:
8
9 # allocate the relevant modules
10 dataset = Dataset(numpy.random.RandomState(123).randn(13,1))
11 pca = PCA_Analysis()
12 pca_batchsize=1000
13
14 # define the control-flow of the algorithm
15 train_pca = SEQ([
16 BUFFER_REPEAT(pca_batchsize, CALL(dataset.next)),
17 FILT(pca.analyze)])
18
19 # run the program
20 train_pca.run()
21
22 The CALL, SEQ, FILT, and BUFFER_REPEAT are control-flow elements. The control-flow elements I
23 defined so far are:
24
25 - CALL - a basic statement, just calls a python function
26 - FILT - like call, but passes the return value of the last CALL or FILT to the python function
27 - SEQ - a sequence of elements to run in order
28 - REPEAT - do something N times (and return None or maybe the last CALL?)
29 - BUFFER_REPEAT - do something N times and accumulate the return value from each iter
30 - LOOP - do something an infinite number of times
31 - CHOOSE - like a switch statement (should rename to SWITCH)
32 - WEAVE - interleave execution of multiple control-flow elements
33 - POPEN - launch a process and return its status when it's complete
34 - PRINT - a shortcut for CALL(print_obj)
35
36
37 We don't have many requirements per-se for the architecture, but I think this design respects
38 and realizes all of them.
39 The advantages of this approach are:
40
41 - algorithms (including partially run ones) are COPYABLE, and SERIALIZABLE
42
43 - algorithms can be executed without seizing control of the python process (the run()
44 method does this, but if you look inside it you'll see it's a simple for loop)
45
46 - it is easy to execute an algorithm step by step in a main loop that also checks for
47 network or filesystem events related to e.g. job management.
48
49 - the library can provide learning algorithms via control-flow templates, and the user can
50 edit them (with search/replace calls) to include HOOKS, and DIAGNOSTIC plug-in
51 functionality
52
53 e.g. prog.find(CALL(cd1_update, layer=layer1)).replace_with(
54 SEQ([CALL(cd1_update, layer=layer1), CALL(my_debugfn)]))
55
56 - user can print the 'program code' of an algorithm built from library pieces
57
58 - program can be optimized automatically.
59
60 - e.g. BUFFER(N, CALL(dataset.next)) could be replaced if dataset.next implements the
61 right attribute/protocol for 'bufferable' or something.
62
63 - e.g. SEQ([a,b,c,d]) could be compiled to a single CALL to a Theano-compiled function
64 if a, b, c, and d are calls to callable objects that export something like a
65 'theano_SEQ' interface
66
67
68 """
69
70 __license__ = 'TODO'
71 __copyright__ = 'TODO'
72
73 import cPickle, copy, os, subprocess, sys, time
74 import numpy
75
76 ####################################################
77 # CONTROL-FLOW CONSTRUCTS
78
79 class INCOMPLETE:
80 """Return value for Element.step"""
81
82 class ELEMENT(object):
83 """
84 Base class for control flow elements (e.g. CALL, REPEAT, etc.)
85
86 The design is that every element has a driver, that is another element, or the iterator
87 implementation in the ELEMENT class.
88
89 the driver calls start when entering a new control element
90 - this would be called once per e.g. outer loop iteration
91
92 the driver calls step to advance the control element
93 - which returns INCOMPLETE
94 - which returns any other object to indicate completion
95 """
96
97 # subclasses should override these methods:
98 def start(self, arg):
99 pass
100 def step(self):
101 pass
102
103 # subclasses should typically not override these:
104 def run(self, arg=None, n_steps=float('inf')):
105 self.start(arg)
106 i = 0
107 r = self.step()
108 while r is INCOMPLETE:
109 i += 1
110 #TODO make sure there is not an off-by-one error
111 if i > n_steps:
112 break
113 r = self.step()
114 return r
115
116 class BUFFER_REPEAT(ELEMENT):
117 """
118 Accumulate a number of return values into one list / array.
119
120 The source of return values `src` is a control element that will be restarted repeatedly in
121 order to fulfil the requiement of gathering N samples.
122
123 TODO: support accumulating of tuples of arrays
124 """
125 def __init__(self, N, src, storage=None):
126 """
127 TODO: use preallocated `storage`
128 """
129 self.N = N
130 self.n = 0
131 self.src = src
132 self.storage = storage
133 self.src.start(None)
134 if self.storage != None:
135 raise NotImplementedError()
136 def start(self, arg):
137 self.buf = [None] * self.N
138 self.n = 0
139 self.finished = False
140 def step(self):
141 assert not self.finished
142 r = self.src.step()
143 if r is INCOMPLETE:
144 return r
145 self.src.start(None) # restart our stream
146 self.buf[self.n] = r
147 self.n += 1
148 if self.n == self.N:
149 self.finished = True
150 return self.buf
151 else:
152 return INCOMPLETE
153 assert 0
154
155 class CALL(ELEMENT):
156 """
157 Control flow terminal - call a python function or method.
158
159 Returns the return value of the call.
160 """
161 def __init__(self, fn, *args, **kwargs):
162 self.fn = fn
163 self.args = args
164 self.kwargs=kwargs
165 self.use_start_arg = kwargs.pop('use_start_arg', False)
166 def start(self, arg):
167 self.start_arg = arg
168 self.finished = False
169 return self
170 def step(self):
171 assert not self.finished
172 self.finished = True
173 if self.use_start_arg:
174 if self.args:
175 raise TypeError('cant get positional args both ways')
176 return self.fn(self.start_arg, **self.kwargs)
177 else:
178 return self.fn(*self.args, **self.kwargs)
179 def __getstate__(self):
180 rval = dict(self.__dict__)
181 if type(self.fn) is type(self.step): #instancemethod
182 fn = rval.pop('fn')
183 rval['i fn'] = fn.im_func, fn.im_self, fn.im_class
184 return rval
185 def __setstate__(self, dct):
186 if 'i fn' in dct:
187 dct['fn'] = type(self.step)(*dct.pop('i fn'))
188 self.__dict__.update(dct)
189
190 def FILT(fn, **kwargs):
191 """
192 Return a CALL object that uses the return value from the previous CALL as the first and
193 only positional argument.
194 """
195 return CALL(fn, use_start_arg=True, **kwargs)
196
197 def CHOOSE(which, options):
198 """
199 Execute one out of a number of optional control flow paths
200 """
201 raise NotImplementedError()
202
203 def LOOP(elements):
204 #TODO: implement a true infinite loop
205 try:
206 iter(elements)
207 return REPEAT(sys.maxint, elements)
208 except TypeError:
209 return REPEAT(sys.maxint, [elements])
210
211 class REPEAT(ELEMENT):
212 def __init__(self, N, elements, pass_rvals=False):
213 self.N = N
214 self.elements = elements
215 self.pass_rvals = pass_rvals
216
217 #TODO: check for N being callable
218 def start(self, arg):
219 self.n = 0 #loop iteration
220 self.idx = 0 #element idx
221 self.finished = False
222 self.elements[0].start(arg)
223 def step(self):
224 assert not self.finished
225 r = self.elements[self.idx].step()
226 if r is INCOMPLETE:
227 return INCOMPLETE
228 self.idx += 1
229 if self.idx < len(self.elements):
230 self.elements[self.idx].start(r)
231 return INCOMPLETE
232 self.n += 1
233 if self.n < self.N:
234 self.idx = 0
235 self.elements[self.idx].start(r)
236 return INCOMPLETE
237 else:
238 self.finished = True
239 return r
240
241 def SEQ(elements):
242 return REPEAT(1, elements)
243
244 class WEAVE(ELEMENT):
245 """
246 Interleave execution of a number of elements.
247
248 TODO: allow a schedule (at least relative frequency) of elements from each program
249 """
250 def __init__(self, n_required, elements):
251 self.elements = elements
252 if n_required == -1:
253 self.n_required = len(elements)
254 else:
255 self.n_required = n_required
256 def start(self, arg):
257 for el in self.elements:
258 el.start(arg)
259 self.elem_finished = [0] * len(self.elements)
260 self.idx = 0
261 self.finished= False
262 def step(self):
263 assert not self.finished # if this is triggered, we have a broken driver
264
265 #start with this check in case there were no elements
266 # it's possible for the number of finished elements to exceed the threshold
267 if sum(self.elem_finished) >= self.n_required:
268 self.finished = True
269 return None
270
271 # step the active element
272 r = self.elements[self.idx].step()
273
274 if r is not INCOMPLETE:
275 self.elem_finished[self.idx] = True
276
277 # check for completion
278 if sum(self.elem_finished) >= self.n_required:
279 self.finished = True
280 return None
281
282 # advance to the next un-finished element
283 self.idx = (self.idx+1) % len(self.elements)
284 while self.elem_finished[self.idx]:
285 self.idx = (self.idx+1) % len(self.elements)
286
287 return INCOMPLETE
288
289 class POPEN(ELEMENT):
290 def __init__(self, args):
291 self.args = args
292 def start(self, arg):
293 self.p = subprocess.Popen(self.args)
294 def step(self):
295 r = self.p.poll()
296 if r is None:
297 return INCOMPLETE
298 return r
299
300 def PRINT(obj):
301 return CALL(print_obj, obj)
302
303 class SPAWN(ELEMENT):
304 SUCCESS = 0
305 def __init__(self, data, prog):
306 self.data = data
307 self.prog = prog
308 def start(self, arg):
309 # pickle the (data, prog) pair
310 s = cPickle.dumps((self.data, self.prog))
311
312 # call python with a stub function that
313 # unpickles the data, prog pair and starts running the prog
314 self.rpipe, wpipe = os.pipe()
315 code = 'import sys, plugin_JB; sys.exit(plugin_JB.SPAWN._main(%i))'%wpipe
316 self.p = subprocess.Popen(
317 ['python', '-c', code],
318 stdin=subprocess.PIPE)
319 # send the data and prog to the other process
320 self.p.stdin.write(s)
321 self.finished= False
322
323 #TODO: send over tgz of the modules this code needs
324
325 #TODO: When the client process is on a different machine, negotiate with the client
326 # process to determine which modules it needs, and send over the code for pure python
327 # ones. Make sure versions match for non-pure python ones.
328
329 def step(self):
330 assert not self.finished
331 r = self.p.poll()
332 if r is None:
333 return INCOMPLETE # typical exit case
334 self.finished = True
335 if r != self.SUCCESS:
336 print "UH OH", r # TODO - ???
337 rfile = os.fdopen(self.rpipe)
338 # recv the revised of the data dictionary
339 data = cPickle.load(rfile)
340 # modify the data dict in-place
341 # for new values to be visible to other components
342 self.data.update(data)
343 rfile.close()
344 #TODO: return something meaningful? like r?
345 return None
346
347 @staticmethod
348 def _main(wpipe):
349 #TODO: unpack and install tgz of the modules this code needs
350 data, prog = cPickle.load(sys.stdin)
351 rval = prog.run()
352 os.write(wpipe, cPickle.dumps(data))
353 return SPAWN.SUCCESS
354 #os.close(wpipe)
355
356
357 def print_obj(obj):
358 print obj
359 def print_obj_attr(obj, attr):
360 print getattr(obj, attr)
361 def no_op(*args, **kwargs):
362 pass
363
364 def importable_fn(d):
365 d['new key'] = len(d)
366