ODE Status Monitoring

[delta-pi-1701]

In Matlab we have 'odeprint' which is very handy in monitoring the Progress of ode, is there any equivalent thing for Sundials-Julia?

[ViralBShah]

I am not sure if there is anything at the moment. However, in the API, I believe it should not be difficult to provide a way to register a post-processing function that gets called after evaluation at every time step.

[delta-pi-1701]

odeprint is really very handy in monitoring the status of ode solver, when sizeof(y_dot) is large and solver takes whole lot of time to solve.

[ViralBShah]

It would be great if you can create a PR. That will be the fastest way to get the functionality in. Otherwise, I am sure one of the regular Sundials contributors will get around to it.

[acroy]

I don't know if there is anything related in the Sundials API, but we could certainly call some monitoring function in our high-level functions cvode and idasol. For example, we could have

abstract ProgressMonitor

# called to initialize progress monitor, eg resetting step counter
function init!(p::ProgressMonitor, tspan, y0)
end

# called after each successful step
function step_done(p::ProgressMonitor, t, y0)
end

# default monitor which does nothing
type DoNothing <: ProgressMonitor
end

# simple monitor which prints each step with the result
type PrintProgress <: ProgressMonitor
end

function step_done(p::PrintProgress, t, y0)
  println("@t=$(t): $(y0)")   # this should give some nicely formatted output
end

And then we make cvode and idasol taking an additional argument of type ProgressMonitor with the default DoNothing(). Users could implement more sophisticated monitors using a progress bar or such.

[ChrisRackauckas]

This will be fixed with Julia v1.0. We'll plug into the base logging system which allows for this information. It separates the information from the display, so from there supporting Juno or console displays would simply be about someone else building a package which supports it (and Juno is already commited to changing their progress displays to this)

[ChrisRackauckas]

The common interface progress bar support has been added, so sol = solve(prob,CVODE_BDF(),progress=true) etc. all works.