Week 10: Coding Period

This week I looked into MultiProcessing Conditions and finished the video of the FSM.

Video

After consulting with Jose Maria Canas, I added extra slides and description to the video. Finally I capped it off by adding subtitles and background music. As my video editing skills have improved somewhat, this video was pretty good :).

Conditions

The next aspect of this week was the focus on Multiprocessing Conditions for the FSM implementation. After trawling through many examples and Python’s Documentation, I got the hang of how Conditions were implemented.

Subsequently I used them through Visual Circuit to implement the FSM. Using Conditions and a shared Value variable, I was able to implement a perfectly working FSM with virtually no changes to the code of the original Visual Circuit program.

The only the differences were as follows: Adding Value and Condition to the main.py file:

fsm = Value('i', 1)
condition = Condition()
.
.
processes.append(
            multiprocessing.Process(target=method, args=(inputs, outputs, parameters, fsm, condition, Synchronise(1 / (freq if freq != 0 else 30))))
        )

This made me change the template of the blocks as follows:

def main(inputs, outputs, parameters, fsm, condition, synchronise):

Finally an example of a block made using Conditions:

def main(inputs, outputs, parameters, fsm, condition, synchronise):
    IS_INITIAL = True

    with condition:
        while True:
            if fsm.value == 1 or IS_INITIAL:
                IS_INITIAL = False
                print("Block 1 is executing ...")
                sleep(1)
                outputs.share_number('o', 2)
                fsm.value = 2
                condition.notify_all()
            else:
                condition.wait()
            synchronise()

Note that the above block was made as a test for how the Conditions worked together with sleep statements. However this method didn’t exactly achive the ‘Visual’ aspect of Visual Circuit’s goal. We’ve decided to look into a way to integrate the Multiprocessing Values with the Visual Circuit interface, maybe by using it as a block?

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