I guess my reasoning rule can't find the defined python function

Alexander Gabriel

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Jan 20, 2020, 4:03:36 PM1/20/20

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Hiya,

with your help I got most of my reasoning running in a test setting, running it under my ROS node though, fails due to the python function (which calculates truth values) not being called.

Does anyone have a clue how the code searches for the function name when we call it like so:

        deduction_rule = BindLink(
            VariableList(
                TypedVariableLink(
                    VariableNode('$A'),
                    TypeNode('ConceptNode')),
                TypedVariableLink(
                    VariableNode('$B'),
                    TypeNode('ConceptNode')),
                TypedVariableLink(
                    VariableNode('$C'),
                    TypeNode('ConceptNode'))),
            AndLink(
                ImplicationLink(
                    VariableNode('$A'),
                    VariableNode('$B')),
                ImplicationLink(
                    VariableNode('$B'),
                    VariableNode('$C')),
                NotLink(
                    EqualLink(
                        VariableNode('$A'),
                        VariableNode('$C')))),
            ExecutionOutputLink(
                GroundedSchemaNode('py: deduction_formula'),
                ListLink(
                    ImplicationLink(
                        VariableNode('$A'),
                        VariableNode('$C')),
                    ImplicationLink(
                        VariableNode('$A'),
                        VariableNode('$B')),
                    ImplicationLink(
                        VariableNode('$B'),
                        VariableNode('$C')))))

I tried to define the deduction formula as the member of the same class in which this happens, as a standalone function at the toplevel of the file as well as an import from another module, none of which was successful.

Best,

Alex

Linas Vepstas

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Jan 20, 2020, 5:07:04 PM1/20/20

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It goes here:

https://github.com/opencog/atomspace/blob/873431bdae3b3f44ed26c47993fee8b2979d7cf9/opencog/atoms/execution/ExecutionOutputLink.cc#L202-L211

and then into here

https://github.com/opencog/atomspace/blob/873431bdae3b3f44ed26c47993fee8b2979d7cf9/opencog/cython/PythonEval.cc#L995

and dives into cython code. But really, all this should work quite well, its tested in assorted unit tests ... so the root cause is ... well I don't know where. Since you're having trouble with this, the fix might be better error detection, better error logging .. finding the problem should not require a dive into the bowels of teh code. Triple-check your error logs ...

--linas

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Alexander Gabriel

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Jan 20, 2020, 5:18:30 PM1/20/20

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Thanks!

what I found out is: the function needs to be defined in the python file that is actually run, not any of those that are imported, even if all the rest of the interaction happens in imported modules and files.

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Linas Vepstas

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Jan 20, 2020, 5:28:49 PM1/20/20

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Well, OK, I'm not sure if that's a bug or not, and at any rate, there should be some error message that would make this clear for the next person. Anatoly, Vitaly, opinions? Can you fix this so that this kind of user-error is easier to track down?

--linas

(I can't cc Anatoly, can't find his email.)

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Alexander Gabriel

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Jan 20, 2020, 5:37:54 PM1/20/20

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There was an error in the log saying that the function couldn't be found

[2020-01-20 17:45:13:345] [ERROR] Python function 'deduction_formula' not found in module '__main__'! (/home/rasberry/git/atomspace/opencog/cython/PythonEval.cc:1003)

that was a helpful hint

(I had stopped looking at it as most of the earlier problems didn't result in log entries)

Thanks again :)

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Vitaly Bogdanov

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Jan 20, 2020, 10:35:54 PM1/20/20

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The simplest way to workaround this is using something like this:

```

__main__.deduction_formula = deduction_formula

```

deduction_formula should be imported before.

The more accurate way is using name of the module as a prefix in GroundedSchemaNode name. To do this your function should be a member of the some Python module:

```

GroundedSchemaNode('py: mymodule.deduction_formula'),

```

You can look at examples at: https://github.com/opencog/atomspace/blob/master/examples/python/ground/ground.py