Best way to handle irregular step sources

[RemDelaporteMathurin]

Hi! I have a source that is a step function but without a regular frequency.

For example, consider the following:

I would like to have a step function for each red block.

What would be the best Source block to handle this in pathsim?

[milanofthe]

I think it would make sense to build a new source block for that. Maybe something similar to the blocks.mixed.Pulse source, that has an end time and can be just a single pulse instead of a pulse sequence as it is currently the case.

Or, repeat a pulse sequence like [T_on_1, T_on_2, T_on_3, ...], [T_off_1, T_off_2, T_off_3, ...]. Should be relatively easy to implement, maybe calling it PulseSequence. I will look into it later and see what I can do.

For now you could check out this example, where a regular Source block is used and accurate timing is realized by the additional Schedule event. Maybe something similar to that will do in the meantime.

[RemDelaporteMathurin]

Thanks @milanofthe for the quick answer! Now if I wanted to use the grey signal as source, do you think that would be possible?

[milanofthe]

In principle yes, but currently there is no block for adding time series data or LUT interpolation, etc. Seems like an obvious necessity though. Again, you could do something crude for now and make sure to limit the simulation timestep dt_max to fully capture the behaviour of your data (with a custom event based block this would be guarenteed):

import numpy as np
from pathsim.blocks import Source

#if you have something like this or arrays, or even pandas dataframes, 
#its just important that they can be interpolated QUICKLY, since this will greatly influence simulation performance
data_t, data_val = [...], [...]

def fnc(t):
    #just using numpy piecewise linear interpolation 
    return np.interp(t, data_t, data_val)

src = Source(fnc)

[milanofthe]

@RemDelaporteMathurin was this sufficient for your case? I plan on extending / refactoring the block library next week, so now would be a good time for specific requests ;)

[RemDelaporteMathurin]

hey, I must admit I haven't had time to try things out yet. Been swamped with a million different things ... :(