1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91

```
//! Compatibility constraints between matrix shapes, e.g., for addition or multiplication.
use crate::base::dimension::{Dim, DimName, Dyn};
/// A type used in `where` clauses for enforcing constraints.
#[derive(Copy, Clone, Debug)]
pub struct ShapeConstraint;
/// Constraints `C1` and `R2` to be equivalent.
pub trait AreMultipliable<R1: Dim, C1: Dim, R2: Dim, C2: Dim>: DimEq<C1, R2> {}
impl<R1: Dim, C1: Dim, R2: Dim, C2: Dim> AreMultipliable<R1, C1, R2, C2> for ShapeConstraint where
ShapeConstraint: DimEq<C1, R2>
{
}
/// Constraints `D1` and `D2` to be equivalent.
pub trait DimEq<D1: Dim, D2: Dim> {
/// This is either equal to `D1` or `D2`, always choosing the one (if any) which is a type-level
/// constant.
type Representative: Dim;
}
impl<D: Dim> DimEq<D, D> for ShapeConstraint {
type Representative = D;
}
impl<D: DimName> DimEq<D, Dyn> for ShapeConstraint {
type Representative = D;
}
impl<D: DimName> DimEq<Dyn, D> for ShapeConstraint {
type Representative = D;
}
macro_rules! equality_trait_decl(
($($doc: expr, $Trait: ident),* $(,)*) => {$(
// XXX: we can't do something like `DimEq<D1> for D2` because we would require a blancket impl…
#[doc = $doc]
pub trait $Trait<D1: Dim, D2: Dim>: DimEq<D1, D2> + DimEq<D2, D1> {
/// This is either equal to `D1` or `D2`, always choosing the one (if any) which is a type-level
/// constant.
type Representative: Dim;
}
impl<D: Dim> $Trait<D, D> for ShapeConstraint {
type Representative = D;
}
impl<D: DimName> $Trait<D, Dyn> for ShapeConstraint {
type Representative = D;
}
impl<D: DimName> $Trait<Dyn, D> for ShapeConstraint {
type Representative = D;
}
)*}
);
equality_trait_decl!(
"Constraints `D1` and `D2` to be equivalent. \
They are both assumed to be the number of \
rows of a matrix.",
SameNumberOfRows,
"Constraints `D1` and `D2` to be equivalent. \
They are both assumed to be the number of \
columns of a matrix.",
SameNumberOfColumns
);
/// Constraints D1 and D2 to be equivalent, where they both designate dimensions of algebraic
/// entities (e.g. square matrices).
pub trait SameDimension<D1: Dim, D2: Dim>:
SameNumberOfRows<D1, D2> + SameNumberOfColumns<D1, D2>
{
/// This is either equal to `D1` or `D2`, always choosing the one (if any) which is a type-level
/// constant.
type Representative: Dim;
}
impl<D: Dim> SameDimension<D, D> for ShapeConstraint {
type Representative = D;
}
impl<D: DimName> SameDimension<D, Dyn> for ShapeConstraint {
type Representative = D;
}
impl<D: DimName> SameDimension<Dyn, D> for ShapeConstraint {
type Representative = D;
}
```