Fix sample_index_u64 for CUDA

juntyr · Jun 9, 2024 · 3e57737 · 3e57737
1 parent 4b40dbf
commit 3e57737
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Showing 2 changed files with 20 additions and 6 deletions.
diff --git a/necsim/core/src/cogs/rng.rs b/necsim/core/src/cogs/rng.rs
@@ -122,7 +122,8 @@ pub trait RngSampler<M: MathsCore>: RngCore<M> {
             clippy::cast_sign_loss
         )]
         let index =
-            M::floor(self.sample_uniform_closed_open().get() * (length.get() as f64)) as u32;
+            M::floor(self.sample_uniform_closed_open().get() * (f64::from(length.sub_one()) + 1.0))
+                as u32;
         // Safety in case of f64 rounding errors
         index.min(length.sub_one())
     }
@@ -139,7 +140,8 @@ pub trait RngSampler<M: MathsCore>: RngCore<M> {
             clippy::cast_sign_loss
         )]
         let index =
-            M::floor(self.sample_uniform_closed_open().get() * (length.get() as f64)) as u64;
+            M::floor(self.sample_uniform_closed_open().get() * ((length.sub_one() as f64) + 1.0))
+                as u64;
         // Safety in case of f64 rounding errors
         index.min(length.sub_one())
     }

diff --git a/necsim/impls/no-std/src/cogs/dispersal_sampler/almost_infinite/downscaled.rs b/necsim/impls/no-std/src/cogs/dispersal_sampler/almost_infinite/downscaled.rs
@@ -118,14 +118,26 @@ impl<M: MathsCore, G: RngCore<M>, D: Clone + DispersalSampler<M, AlmostInfiniteH
             >= non_self_dispersal.non_self_dispersal_rejection_sampling_probability_threshold()
         {
             // if the non-self-dispersal probability is larger (or equal) than the
-            // threshold, use rejection sampling for non-self-dispersal
+            //  threshold, use rejection sampling for non-self-dispersal
             // if the threshold is 1.0, we still favour rejection sampling if the
-            // non-self-dispersal probability is also 1.0 if the threshold is
-            // 0.0, we always use rejection sampling
+            //  non-self-dispersal probability is also 1.0
+            // if the threshold is 0.0, we always use rejection sampling
+            log::info!(
+                "Rejection sampling is used for separate non-self-dispersal, which has a \
+                 probability of {}%",
+                self_dispersal_emperical.one_minus().get() * 100.0
+            );
+
             None
         } else {
             // if the non-self-dispersal probability is smaller than the threshold,
-            // precompute a discrete alias sampler for non-self-dispersal
+            //  precompute a discrete alias sampler for non-self-dispersal
+            log::info!(
+                "A precomputed alias sampler is used for separate non-self-dispersal, which has a \
+                 probability of {}%",
+                self_dispersal_emperical.one_minus().get() * 100.0
+            );
+
             let mut non_self_dispersal = targets
                 .into_iter()
                 .filter_map(|(target, count)| {