src/preadjoint_helper.rs

/*!
Preadjoint construction helper
*/

use std::marker::PhantomData;
use alg_tools::types::*;
pub use alg_tools::linops::*;
use alg_tools::norms::{Norm, HasDualExponent};

/// Helper structure for constructing preadjoints of `S` where `S : Linear<X>`.
/// [`Linear`] needs to be implemented for each instance, but [`Adjointable`]
/// and [`BoundedLinear`] have blanket implementations.
#[derive(Clone,Debug)]
pub struct PreadjointHelper<'a, S : 'a, X> {
    pub forward_op : &'a S,
    _domain : PhantomData<X>
}

impl<'a, S : 'a, X> PreadjointHelper<'a, S, X> {
    pub fn new(forward_op : &'a S) -> Self {
        PreadjointHelper { forward_op, _domain: PhantomData }
    }
}

impl<'a, X, Ypre, S> Adjointable<Ypre, X>
for PreadjointHelper<'a, S, X>
where
    X : Space,
    Ypre : Space,
    Self : Linear<Ypre>,
    S : Clone + Linear<X>
{
    type AdjointCodomain = S::Codomain;
    type Adjoint<'b> = S where Self : 'b;

    fn adjoint(&self) -> Self::Adjoint<'_> {
        self.forward_op.clone()
    }
}

impl<'a, F, X, Ypre, ExpXpre, ExpYpre, S> BoundedLinear<Ypre, ExpYpre, ExpXpre, F>
for PreadjointHelper<'a, S, X>
where
    ExpXpre : HasDualExponent,
    ExpYpre : HasDualExponent,
    F : Float,
    X : Space + Norm<F, ExpXpre::DualExp>,
    Ypre : Space + Norm<F, ExpYpre>,
    Self : Linear<Ypre>,
    S : 'a + Clone + BoundedLinear<X, ExpXpre::DualExp, ExpYpre::DualExp, F>
{
    fn opnorm_bound(&self, expy : ExpYpre, expx : ExpXpre) -> F {
        self.forward_op.opnorm_bound(expx.dual_exponent(), expy.dual_exponent())
    }
}