Extend example

examples/14_toml_template.cpp

@@ -1,6 +1,7 @@
+#include <openPMD/auxiliary/TemplateFile.hpp>
 #include <openPMD/openPMD.hpp>
 
-int main()
+void write()
 {
     std::string config = R"(
 {
@@ -15,7 +16,88 @@ int main()
         "../samples/tomlTemplate.toml", openPMD::Access::CREATE, config);
     auto iteration = writeTemplate.writeIterations()[0];
 
+    openPMD::Dataset ds{openPMD::Datatype::FLOAT, {5, 5}};
+
     auto temperature =
         iteration.meshes["temperature"][openPMD::RecordComponent::SCALAR];
-    temperature.resetDataset({openPMD::Datatype::FLOAT, {5, 5}});
+    temperature.resetDataset(ds);
+
+    auto E = iteration.meshes["E"];
+    E["x"].resetDataset(ds);
+    E["y"].resetDataset(ds);
+    /*
+     * Don't specify datatype and extent for this one to indicate that this
+     * information is not yet known.
+     */
+    E["z"].resetDataset({openPMD::Datatype::UNDEFINED});
+
+    ds.extent = {10};
+
+    auto electrons = iteration.particles["e"];
+    electrons["position"]["x"].resetDataset(ds);
+    electrons["position"]["y"].resetDataset(ds);
+    electrons["position"]["z"].resetDataset(ds);
+
+    electrons["positionOffset"]["x"].resetDataset(ds);
+    electrons["positionOffset"]["y"].resetDataset(ds);
+    electrons["positionOffset"]["z"].resetDataset(ds);
+    electrons["positionOffset"]["x"].makeConstant(3.14);
+    electrons["positionOffset"]["y"].makeConstant(3.14);
+    electrons["positionOffset"]["z"].makeConstant(3.14);
+
+    ds.dtype = openPMD::determineDatatype<uint64_t>();
+    electrons.particlePatches["numParticles"][openPMD::RecordComponent::SCALAR]
+        .resetDataset(ds);
+    electrons
+        .particlePatches["numParticlesOffset"][openPMD::RecordComponent::SCALAR]
+        .resetDataset(ds);
+    electrons.particlePatches["offset"]["x"].resetDataset(ds);
+    electrons.particlePatches["offset"]["y"].resetDataset(ds);
+    electrons.particlePatches["offset"]["z"].resetDataset(ds);
+    electrons.particlePatches["extent"]["x"].resetDataset(ds);
+    electrons.particlePatches["extent"]["y"].resetDataset(ds);
+    electrons.particlePatches["extent"]["z"].resetDataset(ds);
+}
+
+void read()
+{
+    /*
+     * The config is entirely optional, these things are also detected
+     * automatically when reading
+     */
+
+    //     std::string config = R"(
+    // {
+    //   "iteration_encoding": "variable_based",
+    //   "toml": {
+    //     "mode": "template"
+    //   }
+    // }
+    // )";
+
+    openPMD::Series read(
+        "../samples/tomlTemplate.toml", openPMD::Access::READ_ONLY);
+
+    std::string jsonConfig = R"(
+{
+  "iteration_encoding": "variable_based",
+  "json": {
+    "mode": "template"
+  }
+}
+)";
+    openPMD::Series cloned(
+        "../samples/jsonTemplate.json", openPMD::Access::CREATE, jsonConfig);
+    openPMD::auxiliary::initializeFromTemplate(cloned, read, 0);
+    // Have to define the dataset for E/z as it is not defined in the template
+    // @todo check that the dataset is defined only upon destruction, not at
+    // flushing already
+    cloned.writeIterations()[0].meshes["E"]["z"].resetDataset(
+        {openPMD::Datatype::INT});
+}
+
+int main()
+{
+    write();
+    read();
 }