Refactoring and optimisations (#238)

* Strengthened habitat-derived cog pre-conditions

* Fix type layout hacks in lineages and events

* Fix WrappingNoise noise wrapping around 2^32

* Improved CUDA code generation

Author: juntyr

necsim/core/src/cogs/dispersal_sampler.rs

@@ -15,8 +15,8 @@ pub trait DispersalSampler<M: MathsCore, H: Habitat<M>, G: RngCore<M>>:
     crate::cogs::Backup + core::fmt::Debug
 {
     #[must_use]
-    #[debug_requires(habitat.contains(location), "location is inside habitat")]
-    #[debug_ensures(old(habitat).contains(&ret), "target is inside habitat")]
+    #[debug_requires(habitat.is_location_habitable(location), "location is habitable")]
+    #[debug_ensures(old(habitat).is_location_habitable(&ret), "target is habitable")]
     fn sample_dispersal_from_location(
         &self,
         location: &Location,
@@ -33,8 +33,8 @@ pub trait SeparableDispersalSampler<M: MathsCore, H: Habitat<M>, G: RngCore<M>>:
     DispersalSampler<M, H, G>
 {
     #[must_use]
-    #[debug_requires(habitat.contains(location), "location is inside habitat")]
-    #[debug_ensures(old(habitat).contains(&ret), "target is inside habitat")]
+    #[debug_requires(habitat.is_location_habitable(location), "location is habitable")]
+    #[debug_ensures(old(habitat).is_location_habitable(&ret), "target is habitable")]
     #[debug_ensures(&ret != location, "disperses to a different location")]
     fn sample_non_self_dispersal_from_location(
         &self,
@@ -44,7 +44,7 @@ pub trait SeparableDispersalSampler<M: MathsCore, H: Habitat<M>, G: RngCore<M>>:
     ) -> Location;
 
     #[must_use]
-    #[debug_requires(habitat.contains(location), "location is inside habitat")]
+    #[debug_requires(habitat.is_location_habitable(location), "location is habitable")]
     fn get_self_dispersal_probability_at_location(
         &self,
         location: &Location,

necsim/core/src/cogs/habitat.rs

@@ -22,8 +22,15 @@ pub trait Habitat<M: MathsCore>: crate::cogs::Backup + core::fmt::Debug + Sized
     fn get_extent(&self) -> &LandscapeExtent;
 
     #[must_use]
-    fn contains(&self, location: &Location) -> bool {
-        self.get_extent().contains(location)
+    fn is_location_habitable(&self, location: &Location) -> bool {
+        self.get_extent().contains(location) && self.get_habitat_at_location(location) > 0_u32
+    }
+
+    #[must_use]
+    fn is_indexed_location_habitable(&self, indexed_location: &IndexedLocation) -> bool {
+        self.get_extent().contains(indexed_location.location())
+            && (indexed_location.index()
+                < self.get_habitat_at_location(indexed_location.location()))
     }
 
     #[must_use]

necsim/core/src/cogs/lineage_store.rs

@@ -32,8 +32,8 @@ pub trait LocallyCoherentLineageStore<M: MathsCore, H: Habitat<M>>:
 {
     #[must_use]
     #[debug_requires(
-        habitat.contains(indexed_location.location()),
-        "indexed location is inside habitat"
+        habitat.is_indexed_location_habitable(indexed_location),
+        "indexed location is habitable"
     )]
     fn get_global_lineage_reference_at_indexed_location(
         &self,
@@ -42,8 +42,8 @@ pub trait LocallyCoherentLineageStore<M: MathsCore, H: Habitat<M>>:
     ) -> Option<&GlobalLineageReference>;
 
     #[debug_requires(
-        habitat.contains(lineage.indexed_location.location()),
-        "indexed location is inside habitat"
+        habitat.is_indexed_location_habitable(&lineage.indexed_location),
+        "indexed location is habitable"
     )]
     #[debug_ensures(self.get_lineage_for_local_reference(
         &ret
@@ -68,9 +68,10 @@ pub trait LocallyCoherentLineageStore<M: MathsCore, H: Habitat<M>>:
     #[debug_requires(self.get_lineage_for_local_reference(
         &reference
     ).is_some(), "lineage is active")]
-    #[debug_ensures(old(habitat).contains(
-        ret.indexed_location.location()
-    ), "prior location is inside habitat")]
+    #[debug_ensures(
+        old(habitat).is_indexed_location_habitable(&ret.indexed_location),
+        "prior indexed location is habitable"
+    )]
     #[debug_ensures(self.get_lineage_for_local_reference(
         &old(unsafe { crate::cogs::Backup::backup_unchecked(&reference) })
     ).is_none(), "lineage was deactivated")]
@@ -104,7 +105,10 @@ pub trait GloballyCoherentLineageStore<M: MathsCore, H: Habitat<M>>:
     fn iter_active_locations(&self, habitat: &H) -> Self::LocationIterator<'_>;
 
     #[must_use]
-    #[debug_requires(habitat.contains(location), "location is inside habitat")]
+    #[debug_requires(
+        habitat.is_location_habitable(location),
+        "location is habitable"
+    )]
     fn get_local_lineage_references_at_location_unordered(
         &self,
         location: &Location,

necsim/core/src/cogs/speciation_probability.rs

@@ -11,7 +11,10 @@ pub trait SpeciationProbability<M: MathsCore, H: Habitat<M>>:
     crate::cogs::Backup + core::fmt::Debug
 {
     #[must_use]
-    #[debug_requires(habitat.contains(location), "location is inside habitat")]
+    #[debug_requires(
+        habitat.is_location_habitable(location),
+        "location is habitable"
+    )]
     fn get_speciation_probability_at_location(
         &self,
         location: &Location,

necsim/core/src/cogs/turnover_rate.rs

@@ -11,7 +11,10 @@ pub trait TurnoverRate<M: MathsCore, H: Habitat<M>>:
     crate::cogs::Backup + core::fmt::Debug
 {
     #[must_use]
-    #[debug_requires(habitat.contains(location), "location is inside habitat")]
+    #[debug_requires(
+        habitat.is_location_habitable(location),
+        "location is habitable"
+    )]
     #[debug_ensures(
         ret != 0.0_f64 || habitat.get_habitat_at_location(location) == 0_u32,
         "only returns zero if the location is inhabitable"