Hi John,

When I originally did this, I needed CIC deposition in phase space for a project I was working on, so that was the use case I had in mind. I'm wasn't sure that it made sense to use logarithmically-spaced bins for finite-sized particles, so I just disabled log bins for particle phase plots.

But, the default interpolation option is nearest grid point, which should be equivalent to binning. I don't think there's any reason why NGP can't work with log bins. It think the thing to do is soften the check to only disable logging bin_fields when deposition='cic'.

-Andrew

On Fri, May 6, 2016 at 8:39 AM, John Zuhone <jzuhone@gmail.com> wrote:

Hi all,

I had a question about how we do particle phase plots / 2d profiles.

I’ve noticed that we way we do this involves some kind of deposition of the particle data into a grid. This necessitates never allowing one to make log-spaced bins for a particle 2d profile, though you can of course plot them in logspace.

This has rather nasty consequences, however, for data which has a huge dynamic range over orders of magnitude and for which log-spaced bins would make a lot of sense. See, for example, this plot:

http://i.imgur.com/RvCp3uD.png

where a lot of the interesting data is at low density but has simply been swallowed up into the first bin in density space because of the linear spacing, making the plot essentially useless. Note this plot was made with a ridiculous amount of bins, 16000x16000, and it still washes things out at low density too much.

So I guess my questions are:

1. Why do we need to use deposition instead of simply binning up the particle data? Isn’t this what we do for grid-spaced data?

2. Is there any reason why we cannot use log-spaced bins with deposition (even if we have to hack it somehow)?

Best,

John

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