Merge pull request #908 from EnergySystemsModellingLab/empty-input-files

Allow `assets.csv` and `commodity_levies.csv` to be empty

Author: alexdewar

src/input/asset.rs

@@ -1,5 +1,5 @@
 //! Code for reading [Asset]s from a CSV file.
-use super::{input_err_msg, read_csv};
+use super::{input_err_msg, read_csv_optional};
 use crate::agent::AgentID;
 use crate::asset::Asset;
 use crate::id::IDCollection;
@@ -35,15 +35,15 @@ struct AssetRaw {
 ///
 /// # Returns
 ///
-/// A `HashMap` containing assets grouped by agent ID.
+/// A `Vec` of [`Asset`]s or an error.
 pub fn read_assets(
     model_dir: &Path,
     agent_ids: &IndexSet<AgentID>,
     processes: &ProcessMap,
     region_ids: &IndexSet<RegionID>,
 ) -> Result<Vec<Asset>> {
     let file_path = model_dir.join(ASSETS_FILE_NAME);
-    let assets_csv = read_csv(&file_path)?;
+    let assets_csv = read_csv_optional(&file_path)?;
     read_assets_from_iter(assets_csv, agent_ids, processes, region_ids)
         .with_context(|| input_err_msg(&file_path))
 }

src/input/commodity/levy.rs

@@ -1,5 +1,5 @@
 //! Code for reading in the commodity levies CSV file.
-use super::super::{input_err_msg, read_csv, try_insert};
+use super::super::{input_err_msg, read_csv_optional, try_insert};
 use crate::commodity::{BalanceType, CommodityID, CommodityLevy, CommodityLevyMap};
 use crate::id::IDCollection;
 use crate::region::{RegionID, parse_region_str};
@@ -44,7 +44,7 @@ struct CommodityLevyRaw {
 ///
 /// # Returns
 ///
-/// A map containing levies, grouped by commodity ID.
+/// A map containing levies, grouped by commodity ID or an error.
 pub fn read_commodity_levies(
     model_dir: &Path,
     commodity_ids: &IndexSet<CommodityID>,
@@ -53,7 +53,7 @@ pub fn read_commodity_levies(
     milestone_years: &[u32],
 ) -> Result<HashMap<CommodityID, CommodityLevyMap>> {
     let file_path = model_dir.join(COMMODITY_LEVIES_FILE_NAME);
-    let commodity_levies_csv = read_csv::<CommodityLevyRaw>(&file_path)?;
+    let commodity_levies_csv = read_csv_optional(&file_path)?;
     read_commodity_levies_iter(
         commodity_levies_csv,
         commodity_ids,

src/simulation/investment.rs

@@ -123,7 +123,7 @@ pub fn perform_agent_investment(
             }
 
             // Add the selected assets to the list of all selected assets
-            all_selected_assets.extend(selected_assets.clone());
+            all_selected_assets.extend(selected_assets.iter().cloned());
 
             // Perform dispatch optimisation with assets that have been selected so far
             // **TODO**: presumably we only need to do this for selected_assets, as assets added in

src/simulation/optimisation.rs

@@ -161,6 +161,11 @@ pub fn solve_optimal(model: highs::Model) -> Result<highs::SolvedModel> {
         .map_err(|err| anyhow!("Incoherent model: {err:?}"))?;
 
     let status = solved.status();
+    ensure!(
+        status != HighsModelStatus::Infeasible,
+        "The solver has indicated that the problem is infeasible. It may be because the assets in \
+        this year cannot meet the required demand."
+    );
     ensure!(
         status == HighsModelStatus::Optimal,
         "Could not find optimal result for model: {status:?}"