After the installation, all of these tools will be located in the
/path/to/prac/apps directory (which, if you’ve set up your
environment correctly, is within your system PATH).
pracquery - the PRAC Query-Tool, a graphical inference toolA graphical tool, whose usage is hopefully self-explanatory, are part of the package: The inference tool (pracquery.py). Simply invoke it using the Python interpreter. (On Windows, do not use pythonw.exe to run it because the console output is an integral part of the tool.):
python pracquery.py
The tool works with .mln and .db files in a pracmln project file.
A project file is a container in the zip format that has the file
extension .pracmln. The structure of the container is as follows
project-name.pracmln
query.conf
learn.conf
mlns/
...
dbs/
...
It consists of two .conf files that hold the settings of your
inferences and learning procedures (e.g. which algorithms to use
with wich parameters). All .mln files that can be used within
the project must go into the mlns subdirectory, whereas all
.db files must be located in the dbs directory.
By default, all output files will also be written to the current project container.
The tools are designed to be invoked from a console. Simply change to the directory in which the files you want to work with are located and then invoke the tool you want to use, e.g.
$ pracquery -i <Instruction>
The tool will remember this directory for the next session and will automatically start in that directory.
The general workflow is then as follows: You select the files you want to work with, edit them as needed or even create new files directly from within the GUI. Then you set the further options and click on the button at the very bottom to start the procedure.
Once you start the actual algorithm, the tool window itself will be hidden as long as the job is running, while the output of the algorithm is written to the console for you to follow. Once the task is completed, the query tool outputs the inference results to the console.
Files located in a .pracmln project can be accessed my means of
the pracmln.mlnpath class. An MLN Path has the following form:
<path-to-project>:<file-in-project>
where <path-to-project> is a regular relative or absolute file path
to a .pracmln project file and <file-in-project> is the name
of the file in the project. For example, consider that there is a
project file my-project.pracmln in the user’s home directory and we wish to access the
file learnt.mln within that project. Then, this file can be
accessed by the line
from pracmln.utils.project import mlnpath
p = mlnpath('/home/username/my-project.pracmln:learnt.mln')
print p.content
mlnpath returns an object of the type pracmln.mlnpath,
which has the following members:
pracmln.mlnpath(path)¶Loads the MLN resource content from a location.
A location can be a regular absolute or relative path to an .mln file. It may also refer
to an MLN inside a .pracmln project container. In the latter case, the .mln file name
needs to be separated from the .pracmln project location by a colon. Path specification
may also contain references to system environment variables, which are referred to of the
form ${var}.
| Example: |
|---|
>>> mlnpath('~/mlns/classification.pracmln:model-1.mln').content
...
content¶Returns the content of the file specified by this mlnpath.
exists¶Checks if the file exists.
file¶Returns the name of the file specified by this mlnpath.
project¶Returns the project name specified.
projectloc¶Returns the location of the project file, if any is specified.
For every learning/inference task, you must specify which logic calculus is to be used:
Selection of the MLN logic calculus.
The dropdown menus in the MLN and DB sections of the GUIs display all MLN or DB files in the project. In order to inspect or edit a file, just select them from the respective dropdown menu:
File selection in the GUI tools.
If you modify a file, it will be flagged as “dirty”, which is indicated by an asterisk in front of its file name. New, empty files can be added to the project by hitting the “New” button, existing files can be imported from the file system via the “Import…” button. Files can also be renamed by editing their file name in the text box and hitting the “Save” button or removed from the project with “Delete”.
The tools feature integrated editors for .db and .mln files. If you modify a file in an internal editor, it will automatically be saved as soon as you invoke the learning or inference method (i.e. when you press the button at the very bottom) or whenever you press the save button to the right of the dropdown menu. If you want to save to a different filename, you may do so by changing the filename in the text input directly below the editor (which is activated as soon as the editor content changes) and then clicking on the save button. Session Management
The tools will save all the settings you made and all files when you hit the “save project” button. So that you can easily resume a session (all the information is saved to a configuration file). Moreover, the query tool will save context-specific information:
Note
The query tool remembers the query you last made for each evidence database, so when you reselect a database, the query you last made with that database is automatically restored. The model extension that you selected is also associated with the training database (because model extensions typically serve to augment the evidence, e.g. the specification of additional formulas to specify virtual evidence). The additional parameters you specify are saved specific to the inference engine.
There are a couple parameters that both the query tool and the learning tool have in common, which can be set with the respective checkboxes:
multicore=True argument for
algorithms.debug='DEBUG' one can set the
internal log level to DEBUG.For a more detailed overview of the parameters, see inferencemethods and learningmethods.