# the first two arguments are required and the last two are
# optional and initialized to 42 and 0, respectively.
# The last argument, w, is updated with w + x each time the
# function is called.
fn(1) # illegal because there are two required arguments
fn(1, 2) # legal, z is 42, w goes 0 -> 1 (because w <- w + x), returns array(45.0)
fn(1, y = 2) # legal, z is 42, w goes 1 -> 2, returns array(45.0)
fn(x = 1, y = 2) # illegal because x was not named
fn(1, 2, 3) # legal, z is 3, w goes 2 -> 3, returns array(6.0)
fn(1, z = 3, y = 2) # legal, z is 3, w goes 3 -> 4, returns array(6.0)
fn(1, 2, w = 400) # legal, z is 42 again, w goes 400 -> 401, returns array(45.0)
fn(1, 2) # legal, z is 42, w goes 401 -> 402, returns array(45.0)
>>> import theano
>>> from theano import tensor as T
>>> from theano.compile.io import In
>>> x = T.scalar()
>>> y = T.scalar('y')
>>> z = T.scalar('z')
>>> w = T.scalar('w')
>>> fn = theano.function(inputs=[x, y, In(z, value=42), ((w, w+x), 0)],
... outputs=x + y + z)
>>> # the first two arguments are required and the last two are
>>> # optional and initialized to 42 and 0, respectively.
>>> # The last argument, w, is updated with w + x each time the
>>> # function is called.
>>> fn(1) # illegal because there are two required arguments # doctest: +ELLIPSIS
Traceback (most recent call last):
...
TypeError: Missing required input: y
>>> fn(1, 2) # legal, z is 42, w goes 0 -> 1 (because w <- w + x)
array(45.0)
>>> fn(1, y=2) # legal, z is 42, w goes 1 -> 2
array(45.0)
>>> fn(x=1, y=2) # illegal because x was not named # doctest: +ELLIPSIS
Traceback (most recent call last):
...
TypeError: Unknown input or state: x. The function has 3 named inputs (y, z, w), and 1 unnamed input which thus cannot be accessed through keyword argument (use 'name=...' in a variable's constructor to give it a name).
>>> fn(1, 2, 3) # legal, z is 3, w goes 2 -> 3
array(6.0)
>>> fn(1, z=3, y=2) # legal, z is 3, w goes 3 -> 4
array(6.0)
>>> fn(1, 2, w=400) # legal, z is 42 again, w goes 400 -> 401
array(45.0)
>>> fn(1, 2) # legal, z is 42, w goes 401 -> 402
array(45.0)
In the example above, ``z`` has value 42 when no value is explicitly given.
This default value is potentially used at every function invocation, because
...
...
@@ -285,20 +306,25 @@ If a single ``Variable`` or ``Out`` instance is given as argument, then the comp
If a list of ``Variable`` or ``Out`` instances is given as argument, then the compiled function will return a list of their values.
