Fix LDPC Initialization Bug (#23)

Fix LDPC Initialization

hermespy/fec/aff3ct/ldpc.cpp

@@ -29,16 +29,15 @@ class LDPC
         syndromeChecking(syndromeChecking)
     {
         // Read the H matrix
-        this->infoBitPos = std::vector<uint32_t>(dataBlockSize);
-        this->H = std::make_unique<Sparse_matrix>(LDPC_matrix_handler::read(hSourcePath, &infoBitPos));
-
-        // Infer parameters
+        this->H = std::make_unique<Sparse_matrix>(LDPC_matrix_handler::read(hSourcePath));
+        this->codeBlockSize = this->H->get_n_rows();  // N
+        this->dataBlockSize = this->codeBlockSize - this->H->get_n_cols();  // K
+
+        // Create the encoder and decoder
         this->updateRule = std::make_unique<Update_rule_SPA<float>>((unsigned int)this->H->get_cols_max_degree());
-        this->dataBlockSize = this->H->get_n_cols();
-        this->codeBlockSize = this->H->get_n_rows();
 
         this->encoder = std::make_unique<Encoder_LDPC_from_H<int>>(this->dataBlockSize, this->codeBlockSize, *this->H, "IDENTITY", gSavePath, false);   
-        if (this->infoBitPos.size() < 1) this->infoBitPos = this->encoder->get_info_bits_pos();
+        this->infoBitPos = this->encoder->get_info_bits_pos();
 
         this->decoder = std::make_unique<Decoder_LDPC_BP_flooding<int, float>>(this->dataBlockSize, this->codeBlockSize, numIterations, *this->H, infoBitPos, *this->updateRule, syndromeChecking, minNumIterations);
     }
@@ -69,6 +68,11 @@ class LDPC
         return this->codeBlockSize;
     }
 
+    float getRate() const
+    {
+        return (float)this->dataBlockSize / (float)this->codeBlockSize;
+    }
+
     int getNumIterations() const
     {
         return this->numIterations;
@@ -174,6 +178,10 @@ PYBIND11_MODULE(ldpc, m)
             Number of bits within a code block to be decoded.
         )pbdoc")
 
+        .def_property_readonly("rate", &LDPC::getRate, R"pbdoc(
+            Coding rate of the LDPC code.
+        )pbdoc")
+
         .def_property("num_iterations", &LDPC::getNumIterations, &LDPC::setNumIterations, R"pbdoc(
             Number of iterations during decoding.
         )pbdoc")
@@ -182,12 +190,11 @@ PYBIND11_MODULE(ldpc, m)
             C++ bindings are always enabled.
         )pbdoc")
 
-        .def(py::pickle(
-            [](const LDPC& ldpc) {
-                return py::make_tuple(ldpc.getNumIterations(), ldpc.getHSourcePath(), ldpc.getGSavePath(), ldpc.getSyndromeChecking(), ldpc.getMinNumIterations());
-            },
-            [](py::tuple t) {
-                return LDPC(t[0].cast<int>(), t[1].cast<std::string>(), t[2].cast<std::string>(), t[3].cast<bool>(), t[4].cast<int>());
-            }
-        ));
+        .def("__getstate__", [](const LDPC& ldpc) {
+            return py::make_tuple(ldpc.getNumIterations(), ldpc.getHSourcePath(), ldpc.getGSavePath(), ldpc.getSyndromeChecking(), ldpc.getMinNumIterations());
+        })
+
+        .def("__setstate__", [](LDPC& ldpc, py::tuple t) {
+            new (&ldpc) LDPC{t[0].cast<int>(), t[1].cast<std::string>(), t[2].cast<std::string>(), t[3].cast<bool>(), t[4].cast<int>()};
+        });
 }

tests/unit_tests/fec/test_ldpc.py

@@ -28,40 +28,61 @@ class TestLDPCCoding(TestCase):
 
     def setUp(self) -> None:
         # Infer the aff3ct folder location of matrix files relative to this test
-        h_directory = path.join(path.dirname(path.realpath(__file__)), "..", "..", "..", "submodules", "affect", "conf", "dec", "LDPC")
-        self.h_path = path.join(h_directory, "CCSDS_64_128.alist")
+        self.h_directory = path.join(path.dirname(path.realpath(__file__)), "..", "..", "..", "submodules", "affect", "conf", "dec", "LDPC")
+
+        self.h_candidates = [
+            'DEBUG_6_3',
+            'CCSDS_64_128',
+            'MACKAY_504_1008',
+            'WIMAX_288_576',
+        ]
 
         self.g_directory = mkdtemp()
         self.g_path = path.join(self.g_directory, "test.alist")
 
         self.rng = default_rng(42)
-        self.num_attempts = 10
-        self.num_iterations = 10
-
-        self.coding = LDPCCoding(self.num_iterations, self.h_path, self.g_path, False, 10)
+        self.num_attempts = 20
+        self.num_iterations = 100
 
     def tearDown(self) -> None:
         rmtree(self.g_directory)
 
-    def _test_encode_decode(self) -> None:
+    def test_encode_decode(self) -> None:
         """Encoding a data block should yield a valid code."""
-
-        for i in range(self.num_attempts):
-            data_block = self.rng.integers(0, 2, self.coding.bit_block_size, dtype=np.int32)
-            flip_index = self.rng.integers(0, self.coding.bit_block_size)
-
-            code_block = self.coding.encode(data_block)
-            code_block[flip_index] = not bool(code_block[flip_index])
-
-            decoded_block = self.coding.decode(code_block)
-            assert_array_equal(data_block, decoded_block)
-
-    def _test_pickle(self) -> None:
+
+        for h_candidate in self.h_candidates:
+            with self.subTest(h_candidate=h_candidate):
+                h_path = path.join(self.h_directory, h_candidate + ".alist")
+                coding = LDPCCoding(self.num_iterations, h_path, self.g_path, True, 10)
+
+                errors = 0
+                for _ in range(self.num_attempts):
+                    data_block = self.rng.integers(0, 2, coding.bit_block_size, dtype=np.int32)
+                    flip_index = self.rng.integers(0, coding.bit_block_size, dtype=np.int32)
+
+                    code_block = coding.encode(data_block)
+                    code_block[flip_index] = not bool(code_block[flip_index])
+
+                    decoded_block = coding.decode(code_block)
+                    errors += np.sum(data_block != decoded_block)
+
+                self.assertGreater(1, errors, msg=f"Too many errors: {errors}")
+
+    def test_pickle(self) -> None:
         """Pickeling and unpickeling the C++ wrapper"""
 
+        coding = LDPCCoding(self.num_iterations, path.join(self.h_directory, self.h_candidates[0] + '.alist'), "", False, 10)
+
         with NamedTemporaryFile() as file:
-            dump(self.coding, file)
+            dump(coding, file)
             file.seek(0)
 
-            coding = load(file)
-            self.assertEqual(self.num_iterations, coding.num_iterations)
+            deserialized_coding = load(file)
+            self.assertEqual(self.num_iterations, deserialized_coding.num_iterations)
+
+            # Actuall run a full encoding and decoding with the unpickled object
+            data_block = self.rng.integers(0, 2, deserialized_coding.bit_block_size, dtype=np.int32)
+            code_block = deserialized_coding.encode(data_block)
+            decoded_block = deserialized_coding.decode(code_block)
+
+            assert_array_equal(data_block, decoded_block)