[Feature]: Using custom dimensions using DynamicQuantities

[HenryDane]

Feature Request

(Originally a discussion post on the PySR github repository).

I think that it would be useful to be able to use custom AbstractDimensions with this library.

An example of this usecase could be:

# create our dimensions
struct ExtendedDimensions{R} <: AbstractDimensions{R}
    length::R
    mass::R
    time::R
    current::R
    temperature::R
    luminosity::R
    amount::R
    angle::R
    mass_h2o::R
    mass_air::R
    count::R
end

# ... 

const mmr   = Quantity(1.0, ExtendedDimensions(mass_h2o=1, mass_air=-1))
const nconc = Quantity(1.0, ExtendedDimensions(count=1, mass_air=-1))
const dens  = Quantity(1.0, ExtendedDimensions(mass_air=1, length=-3))

X = (; A=data.A * mmr, B=data.B * nconc)
y = data.C * mmr

# create model
model = SRRegressor(
	binary_operators=[*,^,/],
	dimensional_constraint_penalty=10^5,
	nested_constraints=[(^) => [(^) => 0]],
	constraints=[(^) => (-1,1)]
)

Please let me know if there is anything I can do to help with this feature.

[MilesCranmer]

Just copying my comment for anybody else reading this:

as a quick hack, you could treat the other existing units as the units you are interested in. So, e.g., luminosity (cd) could be mass_h20.

But would be nice to allow actual custom dimensions.

[MilesCranmer]

Here's a reduced test that fails:

using SymbolicRegression.InterfaceDynamicQuantitiesModule: get_units, get_si_units
using DynamicQuantities

struct AngleDimensions{R} <: AbstractDimensions{R}
    length::R
    mass::R
    time::R
    current::R
    temperature::R
    luminosity::R
    amount::R
    rad::R
end

const rad = Quantity(1.0, AngleDimensions(; rad=1))

get_si_units(Float64, [dimension(y)])

Basically this code:

SymbolicRegression.jl/src/InterfaceDynamicQuantities.jl

Lines 16 to 57 in cd23a6e

	"""
	get_units(T, D, x, f)
	Gets unit information from a vector or scalar. The first two
	types are the default numeric type and dimensions type, respectively.
	The third argument is the value to get units from, and the fourth
	argument is a function for parsing strings (in case a string is passed)
	"""
	function get_units(args...)
	return error(
	"Unit information must be passed as one of `AbstractDimensions`, `AbstractQuantity`, `AbstractString`, `Function`.",
	)
	end
	function get_units(_, _, ::Nothing, ::Function)
	return nothing
	end
	function get_units(::Type{T}, ::Type{D}, x::AbstractString, f::Function) where {T,D}
	isempty(x) && return one(Quantity{T,D})
	return convert(Quantity{T,D}, f(x))
	end
	function get_units(::Type{T}, ::Type{D}, x::Quantity, ::Function) where {T,D}
	return convert(Quantity{T,D}, x)
	end
	function get_units(::Type{T}, ::Type{D}, x::AbstractDimensions, ::Function) where {T,D}
	return convert(Quantity{T,D}, Quantity(one(T), x))
	end
	function get_units(::Type{T}, ::Type{D}, x::Real, ::Function) where {T,D}
	return Quantity(convert(T, x), D)::Quantity{T,D}
	end
	function get_units(::Type{T}, ::Type{D}, x::AbstractVector, f::Function) where {T,D}
	return Quantity{T,D}[get_units(T, D, xi, f) for xi in x]
	end
	# TODO: Allow for AbstractQuantity output here
	"""
	get_si_units(::Type{T}, units)
	Gets the units with Dimensions{DEFAULT_DIM_BASE_TYPE} type from a vector or scalar.
	"""
	function get_si_units(::Type{T}, units) where {T}
	return get_units(T, Dimensions{DEFAULT_DIM_BASE_TYPE}, units, uparse)
	end

assumes Dimensions is the only AbstractDimensions for units.