Add disable_fallback_components config option

When this is `true`, formulas will be generated without considering
fallback components.

Signed-off-by: Sahas Subramanian <sahas.subramanian@proton.me>

Author: shsms

src/config.rs

@@ -19,4 +19,8 @@ pub struct ComponentGraphConfig {
     /// inverters that have `InverterType::Unspecified` will be assumed to be
     /// Battery inverters.
     pub allow_unspecified_inverters: bool,
+
+    /// Whether to disable fallback components in generated formulas.  When this
+    /// is `true`, the formulas will not include fallback components.
+    pub disable_fallback_components: bool,
 }

src/graph/formulas/fallback.rs

@@ -45,6 +45,12 @@ where
 {
     fn generate(&self, mut component_ids: BTreeSet<u64>) -> Result<Expr, Error> {
         let mut formula = None::<Expr>;
+        if self.graph.config.disable_fallback_components {
+            while let Some(component_id) = component_ids.pop_first() {
+                formula = Self::add_to_option(formula, Expr::component(component_id));
+            }
+            return formula.ok_or(Error::internal("No components to generate formula."));
+        }
         while let Some(component_id) = component_ids.pop_first() {
             if let Some(expr) = self.meter_fallback(component_id)? {
                 formula = Self::add_to_option(formula, expr);
@@ -169,7 +175,7 @@ where
 
 #[cfg(test)]
 mod tests {
-    use crate::{graph::test_utils::ComponentGraphBuilder, Error};
+    use crate::{graph::test_utils::ComponentGraphBuilder, ComponentGraphConfig, Error};
 
     #[test]
     fn test_meter_fallback() -> Result<(), Error> {
@@ -197,6 +203,19 @@ mod tests {
         let expr = graph.fallback_expr(vec![3], true)?;
         assert_eq!(expr.to_string(), "COALESCE(#2, #3, 0.0)");
 
+        let graph = builder.build(Some(ComponentGraphConfig {
+            disable_fallback_components: true,
+            ..Default::default()
+        }))?;
+        let expr = graph.fallback_expr(vec![1, 2], false)?;
+        assert_eq!(expr.to_string(), "#1 + #2");
+
+        let expr = graph.fallback_expr(vec![1, 2], true)?;
+        assert_eq!(expr.to_string(), "#1 + #2");
+
+        let expr = graph.fallback_expr(vec![3], true)?;
+        assert_eq!(expr.to_string(), "#3");
+
         // Add a battery meter with three inverter and three batteries
         let meter_bat_chain = builder.meter_bat_chain(3, 3);
         builder.connect(grid_meter, meter_bat_chain);
@@ -241,6 +260,22 @@ mod tests {
             "COALESCE(#2, #3, 0.0) + COALESCE(#7, 0.0) + COALESCE(#8, 0.0)"
         );
 
+        let graph = builder.build(Some(ComponentGraphConfig {
+            disable_fallback_components: true,
+            ..Default::default()
+        }))?;
+        let expr = graph.fallback_expr(vec![3, 5], false)?;
+        assert_eq!(expr.to_string(), "#3 + #5");
+
+        let expr = graph.fallback_expr(vec![2, 5], true)?;
+        assert_eq!(expr.to_string(), "#2 + #5");
+
+        let expr = graph.fallback_expr(vec![2, 6, 7, 8], true)?;
+        assert_eq!(expr.to_string(), "#2 + #6 + #7 + #8");
+
+        let expr = graph.fallback_expr(vec![2, 7, 8], true)?;
+        assert_eq!(expr.to_string(), "#2 + #7 + #8");
+
         let meter = builder.meter();
         let chp = builder.chp();
         let pv_inverter = builder.solar_inverter();

src/graph/formulas/generators/consumer.rs

@@ -126,7 +126,7 @@ where
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::graph::test_utils::ComponentGraphBuilder;
+    use crate::{graph::test_utils::ComponentGraphBuilder, ComponentGraphConfig};
 
     #[test]
     fn test_zero_consumers() -> Result<(), Error> {
@@ -230,6 +230,23 @@ mod tests {
                 "COALESCE(MAX(0.0, #11 - #8 - #9 - #10), 0.0)"
             )
         );
+        let graph = builder.build(Some(ComponentGraphConfig {
+            disable_fallback_components: true,
+            ..Default::default()
+        }))?;
+        let formula = graph.consumer_formula()?;
+        assert_eq!(
+            formula,
+            concat!(
+                // difference of grid meter from all its suceessors (without fallbacks)
+                "MAX(0.0, #1 - #2 - #5 - #11) + ",
+                // difference of battery meter from battery inverter and pv
+                // meter from the two pv inverters.
+                "COALESCE(MAX(0.0, #2 - #3), 0.0) + COALESCE(MAX(0.0, #5 - #6 - #7), 0.0) + ",
+                // difference of "mixed" meter from its successors.
+                "COALESCE(MAX(0.0, #11 - #8 - #9 - #10), 0.0)"
+            )
+        );
 
         // add a battery chain to the grid meter and a dangling meter to the grid.
         let meter_bat_chain = builder.meter_bat_chain(1, 1);