feat: Add additional metadata to HDF5 outputs.

pywr-core/src/recorders/csv.rs

@@ -106,8 +106,8 @@ impl Recorder for CsvWideFmtOutput {
 
         // This is a vec of vec for each scenario group
         let mut header_scenario_groups = Vec::new();
-        for group_name in domain.scenarios().group_names() {
-            header_scenario_groups.push(vec![format!("scenario-group: {}", group_name)]);
+        for group in domain.scenarios().groups() {
+            header_scenario_groups.push(vec![format!("scenario-group: {}", group.name())]);
         }
 
         for scenario_index in domain.scenarios().indices().iter() {

pywr-core/src/recorders/hdf.rs

@@ -2,15 +2,22 @@ use super::{MetricSetState, PywrError, Recorder, RecorderMeta, Timestep};
 use crate::models::ModelDomain;
 use crate::network::Network;
 use crate::recorders::MetricSetIndex;
-use crate::scenario::ScenarioIndex;
+use crate::scenario::{ScenarioDomain, ScenarioIndex};
 use crate::state::State;
 use chrono::{Datelike, Timelike};
 use hdf5::{Extents, Group};
 use ndarray::{s, Array1};
 use std::any::Any;
 use std::ops::Deref;
 use std::path::PathBuf;
+use std::str::FromStr;
 
+/// A recorder that saves model outputs to an HDF5 file.
+///
+/// This recorder saves the model outputs to an HDF5 file. The file will contain a number of groups
+/// and datasets that correspond to the metrics in the metric set. Additionally, the file will
+/// contain metadata about the time steps and scenarios that were used in the model simulation.
+///
 #[derive(Clone, Debug)]
 pub struct HDF5Recorder {
     meta: RecorderMeta,
@@ -69,7 +76,9 @@ impl Recorder for HDF5Recorder {
             Ok(f) => f,
             Err(e) => return Err(PywrError::HDF5Error(e.to_string())),
         };
-        let mut datasets = Vec::new();
+
+        write_pywr_metadata(&file)?;
+        write_scenarios_metadata(&file, domain.scenarios())?;
 
         // Create the time table
         let dates: Array1<_> = domain.time().timesteps().iter().map(DateTime::from_timestamp).collect();
@@ -83,12 +92,14 @@ impl Recorder for HDF5Recorder {
 
         let metric_set = network.get_metric_set(self.metric_set_idx)?;
 
+        let mut datasets = Vec::new();
+
         for metric in metric_set.iter_metrics() {
             let name = metric.name(network)?;
             let sub_name = metric.sub_name(network)?;
             let attribute = metric.attribute();
 
-            let ds = require_node_dataset(root_grp, shape, name, sub_name, attribute)?;
+            let ds = require_metric_dataset(root_grp, shape, name, sub_name, attribute)?;
 
             datasets.push(ds);
         }
@@ -162,7 +173,7 @@ fn require_dataset<S: Into<Extents>>(parent: &Group, shape: S, name: &str) -> Re
 }
 
 /// Create a node dataset in /parent/name/sub_name/attribute
-fn require_node_dataset<S: Into<Extents>>(
+fn require_metric_dataset<S: Into<Extents>>(
     parent: &Group,
     shape: S,
     name: &str,
@@ -193,3 +204,81 @@ fn require_group(parent: &Group, name: &str) -> Result<Group, PywrError> {
         }
     }
 }
+
+fn write_pywr_metadata(file: &hdf5::File) -> Result<(), PywrError> {
+    let root = file.deref();
+
+    let grp = require_group(root, "pywr")?;
+
+    // Write the Pywr version as an attribute
+    const VERSION: &str = env!("CARGO_PKG_VERSION");
+    let version = hdf5::types::VarLenUnicode::from_str(VERSION).map_err(|e| PywrError::HDF5Error(e.to_string()))?;
+
+    let attr = grp
+        .new_attr::<hdf5::types::VarLenUnicode>()
+        .shape(())
+        .create("pywr-version")
+        .map_err(|e| PywrError::HDF5Error(e.to_string()))?;
+    attr.as_writer()
+        .write_scalar(&version)
+        .map_err(|e| PywrError::HDF5Error(e.to_string()))?;
+
+    Ok(())
+}
+
+#[derive(hdf5::H5Type, Clone, PartialEq, Debug)]
+#[repr(C)]
+pub struct ScenarioGroupEntry {
+    pub name: hdf5::types::VarLenUnicode,
+    pub size: usize,
+}
+
+#[derive(hdf5::H5Type, Clone, PartialEq, Debug)]
+#[repr(C)]
+pub struct H5ScenarioIndex {
+    index: usize,
+    indices: hdf5::types::VarLenArray<usize>,
+}
+
+/// Write scenario metadata to the HDF5 file.
+///
+/// This function will create the `/scenarios` group in the HDF5 file and write the scenario
+/// groups and indices into `/scenarios/groups` and `/scenarios/indices` respectively.
+fn write_scenarios_metadata(file: &hdf5::File, domain: &ScenarioDomain) -> Result<(), PywrError> {
+    // Create the scenario group and associated datasets
+    let grp = require_group(file.deref(), "scenarios")?;
+
+    let scenario_groups: Array1<ScenarioGroupEntry> = domain
+        .groups()
+        .iter()
+        .map(|s| {
+            let name =
+                hdf5::types::VarLenUnicode::from_str(s.name()).map_err(|e| PywrError::HDF5Error(e.to_string()))?;
+
+            Ok(ScenarioGroupEntry { name, size: s.size() })
+        })
+        .collect::<Result<_, PywrError>>()?;
+
+    if let Err(e) = grp.new_dataset_builder().with_data(&scenario_groups).create("groups") {
+        return Err(PywrError::HDF5Error(e.to_string()));
+    }
+
+    let scenarios: Array1<H5ScenarioIndex> = domain
+        .indices()
+        .iter()
+        .map(|s| {
+            let indices = hdf5::types::VarLenArray::from_slice(&s.indices);
+
+            Ok(H5ScenarioIndex {
+                index: s.index,
+                indices,
+            })
+        })
+        .collect::<Result<_, PywrError>>()?;
+
+    if let Err(e) = grp.new_dataset_builder().with_data(&scenarios).create("indices") {
+        return Err(PywrError::HDF5Error(e.to_string()));
+    }
+
+    Ok(())
+}

pywr-core/src/scenario.rs

@@ -112,7 +112,7 @@ impl ScenarioIndex {
 #[derive(Debug)]
 pub struct ScenarioDomain {
     scenario_indices: Vec<ScenarioIndex>,
-    scenario_group_names: Vec<String>,
+    scenario_groups: Vec<ScenarioGroup>,
 }
 
 impl ScenarioDomain {
@@ -131,29 +131,26 @@ impl ScenarioDomain {
 
     /// Return the index of a scenario group by name
     pub fn group_index(&self, name: &str) -> Option<usize> {
-        self.scenario_group_names.iter().position(|n| n == name)
+        self.scenario_groups.iter().position(|g| g.name == name)
     }
 
-    /// Return the name of each scenario group
-    pub fn group_names(&self) -> &[String] {
-        &self.scenario_group_names
+    pub fn groups(&self) -> &[ScenarioGroup] {
+        &self.scenario_groups
     }
 }
 
 impl From<ScenarioGroupCollection> for ScenarioDomain {
     fn from(value: ScenarioGroupCollection) -> Self {
         // Handle creating at-least one scenario if the collection is empty.
         if !value.is_empty() {
-            let scenario_group_names = value.groups.iter().map(|g| g.name.clone()).collect();
-
             Self {
                 scenario_indices: value.scenario_indices(),
-                scenario_group_names,
+                scenario_groups: value.groups,
             }
         } else {
             Self {
                 scenario_indices: vec![ScenarioIndex::new(0, vec![0])],
-                scenario_group_names: vec!["default".to_string()],
+                scenario_groups: vec![ScenarioGroup::new("default", 1)],
             }
         }
     }