--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/python_access/prox_mapping.rs Thu Feb 26 09:32:12 2026 -0500
@@ -0,0 +1,81 @@
+/*!
+Implementation of [`Prox`] for mappings implemented in Python.
+*/
+
+use crate::python_access::process_error;
+
+use super::diff_mapping::intern_many;
+use super::diff_mapping::PythonMapping;
+use alg_tools::convex::Prox;
+use alg_tools::mapping::{ClosedSpace, Instance, Mapping, Space};
+use pyo3::conversion::FromPyObject;
+use pyo3::intern;
+use pyo3::prelude::*;
+use std::marker::PhantomData;
+
+#[derive(Copy, Debug, Clone)]
+/// Marker for PythonMappings that implement Prox
+pub struct HasProx;
+
+impl<'py, Domain> Prox<Domain> for PythonMapping<'py, Domain, f64, HasProx>
+where
+ Domain: ClosedSpace + Clone + for<'a> FromPyObject<'a, 'py, Error = PyErr> + IntoPyObject<'py>,
+{
+ type Prox<'a>
+ = PythonProx<'py, Domain>
+ where
+ Self: 'a;
+
+ fn prox_mapping(&self, τ: Self::Codomain) -> Self::Prox<'_> {
+ PythonProx { τ, obj: self.get_obj(), _phantoms: PhantomData }
+ }
+}
+
+#[derive(Debug)]
+pub struct PythonProx<'py, Domain>
+where
+ Domain: Space + for<'a> FromPyObject<'a, 'py>,
+{
+ τ: f64,
+ obj: Bound<'py, PyAny>,
+ _phantoms: PhantomData<Domain>,
+}
+
+impl<'py, Domain> Mapping<Domain> for PythonProx<'py, Domain>
+where
+ Domain: ClosedSpace + for<'a> FromPyObject<'a, 'py, Error = PyErr> + IntoPyObject<'py>,
+{
+ type Codomain = Domain;
+
+ /// Compute the value of `self` at `x`.
+ fn apply<I: Instance<Domain>>(&self, x: I) -> Self::Codomain {
+ // TODO: use references and internal mutability?
+ let apply = intern!(self.obj.py(), "prox");
+ process_error(
+ "PythonProx::apply",
+ self.obj.py(),
+ self.obj
+ .call_method1(apply, (self.τ, x.own()))
+ .and_then(|r| r.extract()),
+ )
+ .unwrap()
+ }
+}
+
+impl<'a, 'py, Domain, Codomain> FromPyObject<'a, 'py>
+ for PythonMapping<'py, Domain, Codomain, HasProx>
+where
+ Domain: Space,
+ Codomain: ClosedSpace + FromPyObject<'a, 'py>,
+{
+ type Error = PyErr;
+
+ fn extract(obj_: Borrowed<'a, 'py, PyAny>) -> PyResult<Self> {
+ let obj = obj_.to_owned();
+ // Verify that the necessary methods exist
+ for method in intern_many!(obj.py(), "apply", "prox") {
+ obj.getattr(method)?; //.downcast::<PyFunction>()?;
+ }
+ Ok(PythonMapping { obj, _phantoms: PhantomData })
+ }
+}