Transforms

Particle transforms scale each particle’s foot before the footprint is made (see Particle Weighting (Transforms)). A transform is any object with an apply(particles, context) method. The built-ins are pydantic models, and their fields are their config.yaml keys.

Interface

stilt.ParticleTransform	Interface for a transform: any object with apply(particles, context) -> DataFrame.
stilt.TransformContext	Information about the simulation a transform is applied for.

Built-in transforms

stilt.transforms.AveragingKernel	Transform that weights each particle's foot by an averaging kernel.
stilt.transforms.PressureWeighting	Transform that weights each particle by its share of the column's air mass.
stilt.transforms.FirstOrderLifetime	Transform that decays each particle's foot by exp(-age / lifetime).

Averaging-kernel tables

stilt.transforms.averaging_kernel_table

Return a table of averaging kernels, one per receptor, for AveragingKernel.

Science helpers

stilt.transforms.release_coordinate	Return each particle's value of coordinate at release, indexed by indx.
stilt.transforms.particle_pwf	Return each particle's release pressure and pressure weight.
stilt.transforms.ak_weights	Return the averaging kernel at each particle's release coordinate.

Loading and dumping

stilt.transforms.load_transform	Return the transform for one config entry.
stilt.transforms.dump_transform	Return the config mapping for one transform, the inverse of load_transform().
stilt.transforms.apply_transforms	Apply transforms in order.