PhET-iO instrumentation of sampling models

[pixelzoom]

Related to #231 (PhET-iO instrumentation for particles) and #236 (PhET-iO support for data fluency) ...

The following things sample the particle system:

• AverageSpeedModel - the Average Speed accordion box in the Energy screen, an average of samples collected during a fixed period of time
• HistogramModel - the Speed and KE histograms in the Energy screen, an average of samples collected during a fixed time period
• ParticleFlowRateModel - the flow rate arrows shown in the Diffusion screen, a running average of a constant number of samples

For each of these, the samples need to be stateful. For the elements that involve a fixed time period, the accumulated time must also be stateful.

[pixelzoom]

Most of this work was done as part of #30, #77, and #231. In the above commits, documentation for IOTypes was improved.

[pixelzoom]

@arouinfar @Nancy-Salpepi @kathy-phet This is ready for review. Below is a summary of the relevant PhET-iO elements.

Average Speed

heavyAverageSpeedProperty and lightAverageSpeedProperty are the (running) average speeds for heavy and light particles respectively, as displayed in the Average Speed accordion box. These Properties are phetioFeatured: true.

averageSpeedModel handles serialization of internal elements that are used to derive the above Properties. All of its fields are for internal use only, so it is phetioFeatured: false. AverageSpeedModelIO is its IOType, which looks like this in Studio:

Speed and KE histograms

heavyKineticEnergyBinCountsProperty, lightKineticEnergyBinCountsProperty, and totalKineticEnergyBinCountsProperty are the bin counts displayed by the Kinetic Energy histogram. These Propertes are phetioFeatured: true.

heavySpeedBinCountsProperty, lightSpeedBinCountsProperty, and totalSpeedBinCountsProperty are the bin counts displayed by the Speed histogram. These Propertes are phetioFeatured: true.

histogramsModel handles serialization of internal elements that are used to derive the above Properties. All of its fields are for internal use only, so it is phetioFeatured: false. HistogramsModelIO is its IOType, which looks like this in Studio:

Particle Flow Rate

particle1FlowRateModel.leftFlowRateProperty and particle1FlowRateModel.rightFlowRateProperty are the left and right flow rates displayed for particles of type 1. These Propertes are phetioFeatured: true.

particle2FlowRateModel.leftFlowRateProperty and particle2FlowRateModel.rightFlowRateProperty are the left and right flow rates displayed for particles of type 2. These Propertes are phetioFeatured: true.

particle1FlowRateModel and particle2FlowRateModel handle serialization of internal elements that are used to derive the above Properties. All of their fields are for internal use only, so they are phetioFeatured: false. ParticleFlowRateModelIO is their IOType, which looks like this in Studio:

[pixelzoom]

In #235, serialization of the histograms was optimized. HistogramsModelIO now look like this. Rather than storing raw samples of speed and KE, the samples are immediately processed into "cumulative bins", then averaged later. This greatly reduces the amount of serialized data.

[pixelzoom]

@arouinfar and @Nancy-Salpepi noted a potential problem with restoring state for the Speed histogram, tracking in #261.

@arouinfar @Nancy-Salpepi if everything else looks OK here, and the state schemas look reasonable, please close this issue.

[arouinfar]

@arouinfar @Nancy-Salpepi if everything else looks OK here, and the state schemas look reasonable, please close this issue.

Looks good, closing.