Feature/node probe

[mpu-creare]

Adds a utility method to probe a node/pipeline at a point. It evaluates EVERY node in the pipeline, even if it is not being used.

See the unit tests for expected usage.

[mpu-creare]

@jmilloy could you please spare a few minutes to review and merge when happy.

[coveralls]

Coverage decreased (-88.4%) to 0.0% when pulling 35adfd0 on feature/node_probe into b43613f on develop.

[coveralls]

Coverage decreased (-0.7%) to 87.751% when pulling cb2d494 on feature/node_probe into b43613f on develop.

[mpu-creare]

@jmilloy let me know if/when you are happy and I'll merge.

[jmilloy]

This looks good. I just had one question about the OrderedCompositer active loop.

[jmilloy]

I added a test for the case I'm concerned about. Now I think I get what you are doing (you check the source values and mark the source active if it matches the orderedcompositor value), so I was able to make a test that fails. See d812b92.

[jmilloy]

Hold on, I jumped the gun. Just a sec.

[mpu-creare]

Oh True... I see what you mean... Yeah, if two sources give the same value they would both be marked active. That does need a fix.

[jmilloy]

Okay, I fixed the test. It now fails only because of the active flag.

[mpu-creare]

ok, let me fix it.

[jmilloy]

It was a bit tricky because if two OrderedCompositor sources are the same (not object, but definition/hash), only one of them shows up in the compositor definition. So of course only one shows up in the probe output. I'm not sure if that should be considered a bug or a feature!

>>> a = podpac.data.Array(source=np.ones(3), coordinates=podpac.Coordinates([[0, 1, 2]], dims=['time'])) 
>>> b = podpac.data.Array(source=np.ones(3), coordinates=podpac.Coordinates([[0, 1, 2]], dims=['time'])) 
>>> c = podpac.compositor.OrderedCompositor(sources=[a, b])
>>> c.probe(time=1)
OrderedDict([('Array', {'active': True, 'value': 1.0, 'inputs': [], 'name': 'Array', 'node_hash': 'e032d95041f8076a2a6317c079ace615'}), ('OrderedCompositor', {'active': True, 'value': 1.0, 'inputs': ['Array', 'Array'], 'name': 'OrderedCompositor', 'node_hash': '98354d0bc306ec5c8657590e04c0969a'})])

[jmilloy]

Here's another fun one. Fails because the class isn't available in the global scope:

>>> def fn():
...     class AnotherOne(podpac.algorithm.Algorithm):
...         def algorithm(self, inputs, coordinates):
...             return self.create_output_array(coordinates, data=1)
...     c = podpac.compositor.OrderedCompositor(sources=[a, b, AnotherOne()])
...     c.probe(time=1)
... 
>>> fn()
Traceback (most recent call last):
  File "/home/jmilloy/Creare/Pipeline/podpac/podpac/core/node.py", line 816, in from_definition
    node_class = getattr(module, node_name)
AttributeError: module '__main__' has no attribute 'AnotherOne'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<stdin>", line 6, in fn
  File "/home/jmilloy/Creare/Pipeline/podpac/podpac/core/node.py", line 418, in probe
    return probe_node(self, lat, lon, time, alt)
  File "/home/jmilloy/Creare/Pipeline/podpac/podpac/core/utils.py", line 556, in probe_node
    n = podpac.Node.from_definition(d)
  File "/home/jmilloy/Creare/Pipeline/podpac/podpac/core/node.py", line 818, in from_definition
    raise ValueError(
ValueError: Invalid definition for node 'AnotherOne': class 'AnotherOne' not found in module '__main__'

In the test, I had to define the AnotherOne class globally instead of in the test method.

Again, not sure if this is a bug or just the way things are...

[mpu-creare]

I'll call it a feature. :) Fixed in d938580 Thanks for flagging.