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pytensor
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236f7544
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236f7544
authored
7月 23, 2015
作者:
Iban Harlouchet
提交者:
Arnaud Bergeron
9月 08, 2015
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testcode for doc/tutorial/examples.txt
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examples.txt
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doc/tutorial/examples.txt
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236f7544
...
...
@@ -40,9 +40,11 @@ Well, what you do is this:
.. If you modify this code, also change :
.. theano/tests/test_tutorial.py:T_examples.test_examples_1
>>> import theano
>>> import theano.tensor as T
>>> x = T.dmatrix('x')
>>> s = 1 / (1 + T.exp(-x))
>>> logistic = function([x], s)
>>> logistic =
theano.
function([x], s)
>>> logistic([[0, 1], [-1, -2]])
array([[ 0.5 , 0.73105858],
[ 0.26894142, 0.11920292]])
...
...
@@ -63,7 +65,7 @@ We can verify that this alternate form produces the same values:
.. theano/tests/test_tutorial.py:T_examples.test_examples_2
>>> s2 = (1 + T.tanh(x / 2)) / 2
>>> logistic2 = function([x], s2)
>>> logistic2 =
theano.
function([x], s2)
>>> logistic2([[0, 1], [-1, -2]])
array([[ 0.5 , 0.73105858],
[ 0.26894142, 0.11920292]])
...
...
@@ -83,7 +85,7 @@ squared difference between two matrices *a* and *b* at the same time:
>>> diff = a - b
>>> abs_diff = abs(diff)
>>> diff_squared = diff**2
>>> f = function([a, b], [diff, abs_diff, diff_squared])
>>> f =
theano.
function([a, b], [diff, abs_diff, diff_squared])
.. note::
`dmatrices` produces as many outputs as names that you provide. It is a
...
...
@@ -95,11 +97,9 @@ was reformatted for readability):
>>> f([[1, 1], [1, 1]], [[0, 1], [2, 3]])
[array([[ 1., 0.],
[-1., -2.]]),
array([[ 1., 0.],
[ 1., 2.]]),
array([[ 1., 0.],
[ 1., 4.]])]
[-1., -2.]]), array([[ 1., 0.],
[ 1., 2.]]), array([[ 1., 0.],
[ 1., 4.]])]
Setting a Default Value for an Argument
...
...
@@ -113,6 +113,7 @@ one. You can do it like this:
.. theano/tests/test_tutorial.py:T_examples.test_examples_6
>>> from theano import Param
>>> from theano import function
>>> x, y = T.dscalars('x', 'y')
>>> z = x + y
>>> f = function([x, Param(y, default=1)], z)
...
...
@@ -257,8 +258,7 @@ for the purpose of one particular function.
>>> # The type of foo must match the shared variable we are replacing
>>> # with the ``givens``
>>> foo = T.scalar(dtype=state.dtype)
>>> skip_shared = function([inc, foo], fn_of_state,
givens=[(state, foo)])
>>> skip_shared = function([inc, foo], fn_of_state, givens=[(state, foo)])
>>> skip_shared(1, 3) # we're using 3 for the state, not state.value
array(7)
>>> state.get_value() # old state still there, but we didn't use it
...
...
@@ -311,7 +311,7 @@ Here's a brief example. The setup code is:
.. If you modify this code, also change :
.. theano/tests/test_tutorial.py:T_examples.test_examples_9
..
code-block:: python
..
testcode::
from theano.tensor.shared_randomstreams import RandomStreams
from theano import function
...
...
@@ -382,6 +382,8 @@ For example:
>>> state_after_v0 = rv_u.rng.get_value().get_state()
>>> nearly_zeros() # this affects rv_u's generator
array([[ 0., 0.],
[ 0., 0.]])
>>> v1 = f()
>>> rng = rv_u.rng.get_value(borrow=True)
>>> rng.set_state(state_after_v0)
...
...
@@ -410,8 +412,9 @@ corresponding to the random number generation process (i.e. RandomFunction{unifo
An example of how "random states" can be transferred from one theano function
to another is shown below.
..
code-block:: python
..
testcode::
from __future__ import print_function
import theano
import numpy
import theano.tensor as T
...
...
@@ -429,9 +432,9 @@ to another is shown below.
g2 = Graph(seed=987)
f2 = theano.function([], g2.y)
print
'By default, the two functions are out of sync.'
print
'f1() returns ', f1(
)
print
'f2() returns ', f2(
)
print
('By default, the two functions are out of sync.')
print
("f1() returns ", end=" "); print(f1()
)
print
("f2() returns ", end=" "); print(f2()
)
def copy_random_state(g1, g2):
if isinstance(g1.rng, MRG_RandomStreams):
...
...
@@ -439,19 +442,19 @@ to another is shown below.
for (su1, su2) in zip(g1.rng.state_updates, g2.rng.state_updates):
su2[0].set_value(su1[0].get_value())
print
'We now copy the state of the theano random number generators.'
print
('We now copy the state of the theano random number generators.')
copy_random_state(g1, g2)
print
'f1() returns ', f1(
)
print
'f2() returns ', f2(
)
print
("f1() returns ", end=" "); print(f1()
)
print
("f2() returns ", end=" "); print(f2()
)
This gives the following output:
..
code-block:: bash
..
testoutput::
#
By default, the two functions are out of sync.
By default, the two functions are out of sync.
f1() returns [ 0.72803009]
f2() returns [ 0.55056769]
#
We now copy the state of the theano random number generators.
We now copy the state of the theano random number generators.
f1() returns [ 0.59044123]
f2() returns [ 0.59044123]
...
...
@@ -487,50 +490,66 @@ A Real Example: Logistic Regression
The preceding elements are featured in this more realistic example.
It will be used repeatedly.
..
code-block:: python
..
testcode::
import numpy
import theano
import theano.tensor as T
rng = numpy.random
import numpy
import theano
import theano.tensor as T
rng = numpy.random
N = 400
feats = 784
D = (rng.randn(N, feats), rng.randint(size=N, low=0, high=2))
training_steps = 10000
N = 400
feats = 784
D = (rng.randn(N, feats), rng.randint(size=N, low=0, high=2))
training_steps = 10000
# Declare Theano symbolic variables
x = T.dmatrix("x")
y = T.dvector("y")
w = theano.shared(rng.randn(feats), name="w")
b = theano.shared(0., name="b")
print "Initial model:"
print w.get_value(), b.get_value()
# Construct Theano expression graph
p_1 = 1 / (1 + T.exp(-T.dot(x, w) - b)) # Probability that target = 1
prediction = p_1 > 0.5 # The prediction thresholded
xent = -y * T.log(p_1) - (1-y) * T.log(1-p_1) # Cross-entropy loss function
cost = xent.mean() + 0.01 * (w ** 2).sum()# The cost to minimize
gw, gb = T.grad(cost, [w, b]) # Compute the gradient of the cost
# (we shall return to this in a
# following section of this tutorial)
# Compile
train = theano.function(
inputs=[x,y],
outputs=[prediction, xent],
updates=((w, w - 0.1 * gw), (b, b - 0.1 * gb)))
predict = theano.function(inputs=[x], outputs=prediction)
# Train
for i in range(training_steps):
pred, err = train(D[0], D[1])
print "Final model:"
print w.get_value(), b.get_value()
print "target values for D:", D[1]
print "prediction on D:", predict(D[0])
# Declare Theano symbolic variables
x = T.matrix("x")
y = T.vector("y")
w = theano.shared(rng.randn(feats), name="w")
b = theano.shared(0., name="b")
print("Initial model:")
print(w.get_value())
print(b.get_value())
# Construct Theano expression graph
p_1 = 1 / (1 + T.exp(-T.dot(x, w) - b)) # Probability that target = 1
prediction = p_1 > 0.5 # The prediction thresholded
xent = -y * T.log(p_1) - (1-y) * T.log(1-p_1) # Cross-entropy loss function
cost = xent.mean() + 0.01 * (w ** 2).sum()# The cost to minimize
gw, gb = T.grad(cost, [w, b]) # Compute the gradient of the cost
# (we shall return to this in a
# following section of this tutorial)
# Compile
train = theano.function(
inputs=[x,y],
outputs=[prediction, xent],
updates=((w, w - 0.1 * gw), (b, b - 0.1 * gb)))
predict = theano.function(inputs=[x], outputs=prediction)
# Train
for i in range(training_steps):
pred, err = train(D[0], D[1])
print("Final model:")
print(w.get_value())
print(b.get_value())
print("target values for D:")
print(D[1])
print("prediction on D:")
print(predict(D[0]))
.. testoutput::
:hide:
:options: +ELLIPSIS
Initial model:
...
...
Final model:
...
...
target values for D:
...
prediction on D:
...
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