Description
Something that would be nice to have is the ability to constrain the size of an array. I think the example of a "video" type is a good motivating case - if we are accepting an RGB Video, we want to be able to express "x and y axes of any size, but channels == 3"
I used min_cardinality and max_cardinality in nwb-linkml for this, such that for an RGBImage one expresses the array component as (with minor adjustments to match linkml-array syntax):
RGBImage__Array:
name: RGBImage__Array
is_a: linkml:NDArray
attributes:
x:
implements:
- linkml:axis
name: x
range: numeric
required: true
y:
implements:
- linkml:axis
name: y
range: numeric
required: true
r, g, b:
implements:
- linkml:axis
name: r, g, b
range: numeric
required: true
minimum_cardinality: 3
maximum_cardinality: 3creates a pydantic model like this (i also collapse the array class into the parent class that has other attributes there, but you get the idea)
class RGBImage(Image):
"""
A color image.
"""
linkml_meta: ClassVar[LinkML_Meta] = Field(LinkML_Meta(tree_root=True), frozen=True)
name: str = Field(...)
array: Optional[NDArray[Shape["* x, * y, 3 r_g_b"], Number]] = Field(None)
resolution: Optional[float] = Field(None, description="""Pixel resolution of the image, in pixels per centimeter.""")
description: Optional[str] = Field(None, description="""Description of the image.""")what do y'all think about having that be the means of specifying array sizes? It seems to match the semantics of that slot as its used elsewhere, and so we basically get it for free right?
If there was one suggestion i'd make to a change to the metamodel, it's sort of awkward to have to specify both the max and min to say that cardinality should == a value, so it might be nice to change that to work like:
# cardinality is exactly three
cardinality: 3
# minimum only
cardinality:
min: 3
# range
cardinality:
min: 3
max: 5but that's just a "nice to have" not a critical thing