Rename serialized -> parameterized

Updates to examples and tests to refer to parameterized sources rather
than serialized sources.
Small update to source.h to remove reference to serialized parameters.

examples/parameterized_custom_source/parameterized_source_ring.cpp

@@ -0,0 +1,74 @@
+#include <cmath> // for M_PI
+#include <unordered_map>
+
+#include "openmc/random_lcg.h"
+#include "openmc/source.h"
+#include "openmc/particle.h"
+
+class ParameterizedSource : public openmc::CustomSource {
+  protected:
+    double radius_;
+    double energy_;
+
+    // Protect the constructor so that the class can only be created by serialisation.
+    ParameterizedSource(double radius, double energy) {
+      radius_ = radius;
+      energy_ = energy;
+    }
+
+  public:
+    // Getters for the values that we want to use in sampling.
+    double radius() { return radius_; }
+    double energy() { return energy_; }
+
+    // Defines a function that can create a pointer to a new instance of this class
+    // by deserializing from the provided string.
+    static ParameterizedSource* from_string(const char* parameters) {
+      std::unordered_map<std::string, std::string> parameter_mapping;
+
+      std::stringstream ss(parameters);
+      std::string parameter;
+      while (std::getline(ss, parameter, ',')) {
+        parameter.erase(0, parameter.find_first_not_of(' '));
+        std::string key = parameter.substr(0, parameter.find_first_of('='));
+        std::string value = parameter.substr(parameter.find_first_of('=') + 1, parameter.length());
+        parameter_mapping[key] = value;
+      }
+
+      return new ParameterizedSource(std::stod(parameter_mapping["radius"]), std::stod(parameter_mapping["energy"]));
+    }
+
+    // Samples from an instance of this class.
+    openmc::Particle::Bank sample_source(uint64_t* seed) {
+      openmc::Particle::Bank particle;
+      // wgt
+      particle.particle = openmc::Particle::Type::neutron;
+      particle.wgt = 1.0;
+      // position
+      double angle = 2. * M_PI * openmc::prn(seed);
+      double radius = this->radius();
+      particle.r.x = radius * std::cos(angle);
+      particle.r.y = radius * std::sin(angle);
+      particle.r.z = 0.0;
+      // angle
+      particle.u = {1.0, 0.0, 0.0};
+      particle.E = this->energy();
+      particle.delayed_group = 0;
+
+      return particle;
+    }
+};
+
+// A function to create a pointer to an instance of this class when generated
+// via a plugin call using dlopen/dlsym.
+// You must have external C linkage here otherwise dlopen will not find the file
+extern "C" ParameterizedSource* create(const char* parameters) {
+  return ParameterizedSource::from_string(parameters);
+}
+
+// A function to destroy a pointer to an instance of this class when generated
+// via a plugin call using dlopen/dlsym.
+// You must have external C linkage here otherwise dlopen will not find the file
+extern "C" void destroy(ParameterizedSource* source) {
+  delete source;
+}