From 98181933861614e80be1f8be1c82b48caf9d831a Mon Sep 17 00:00:00 2001
From: Andreas Tsouchlos <an.tsouchlos@gmail.com>
Date: Fri, 25 Nov 2022 11:36:57 +0100
Subject: [PATCH] Return nullopt on decoding failure

---
 sw/cpp/src/cpp_decoders.cpp | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/sw/cpp/src/cpp_decoders.cpp b/sw/cpp/src/cpp_decoders.cpp
index 4a50b2d..e7f102e 100644
--- a/sw/cpp/src/cpp_decoders.cpp
+++ b/sw/cpp/src/cpp_decoders.cpp
@@ -2,6 +2,7 @@
 #include <iostream>
 #include <pybind11/numpy.h>
 #include <pybind11/pybind11.h>
+#include <pybind11/stl.h>
 
 #include <pybind11/eigen.h>
 
@@ -67,7 +68,7 @@ public:
           mH_zero_indices(find_zero(H)) {
     }
 
-    const Eigen::RowVectorXi
+    const std::optional<Eigen::RowVectorXi>
     decode(const Eigen::Ref<const Eigen::VectorXd>& y) {
         Eigen::RowVectorXd s = Eigen::RowVectorXd::Zero(mH.cols());
         Eigen::RowVectorXi x_hat;
@@ -85,8 +86,7 @@ public:
             }
         }
 
-        return x_hat;
-        // TODO: Return 'None'
+        return std::nullopt;
     }
 
 private:
@@ -128,7 +128,7 @@ private:
         B_sums = B_sums * mH.cast<double>();
 
         Eigen::RowVectorXd result = 4 * (x.array().pow(2) - 1) * x.array() +
-                                 (2 * x.array().inverse()) * B_sums.array();
+                                    (2 * x.array().inverse()) * B_sums.array();
 
         return result;
     }
@@ -151,6 +151,7 @@ PYBIND11_MODULE(cpp_decoders, proximal) {
 
     pybind11::class_<ProximalDecoder>(proximal, "ProximalDecoder")
         .def(pybind11::init<MatrixXiR, int, double, double, double>(),
-             "H"_a.noconvert(), "K"_a, "omega"_a, "gamma"_a, "eta"_a)
+             "H"_a.noconvert(), "K"_a = 100, "omega"_a = 0.0002,
+             "gamma"_a = .05, "eta"_a = 1.5)
         .def("decode", &ProximalDecoder::decode, "x"_a.noconvert());
 }
\ No newline at end of file