glotzerlab · joaander · Nov 12, 2025 · Nov 11, 2025 · Nov 11, 2025 · Nov 11, 2025
diff --git a/.bumpversion.cfg b/.bumpversion.cfg
diff --git a/.bumpversion.toml b/.bumpversion.toml
@@ -0,0 +1,28 @@
+[tool.bumpversion]
+current_version = "0.7.1"
+
+[[tool.bumpversion.files]]
+filename = "Cargo.toml"
+search = 'version = "{current_version}"'
+replace = 'version = "{new_version}"'
+
+[[tool.bumpversion.files]]
+filename = ".github/ISSUE_TEMPLATE/bug_report.yml"
+search = """
+      description: What version of **row** are you using?
+      placeholder: {current_version}"""
+
+replace = """
+      description: What version of **row** are you using?
+      placeholder: {new_version}"""
+
+[[tool.bumpversion.files]]
+filename = ".github/ISSUE_TEMPLATE/release.md"
+search = "Release {current_version}"
+replace = "Release {new_version}"
+
+[[tool.bumpversion.files]]
+filename = "doc/src/release-notes.md"
+regex = true
+search = 'Next release$'
+replace = '{new_version} ({now:%Y-%m-%d})'
diff --git a/.github/ISSUE_TEMPLATE/release.md b/.github/ISSUE_TEMPLATE/release.md
@@ -8,14 +8,14 @@ assignees: 'joaander'
 ---
 
 - [ ] Run `prek autoupdate`.
-- [ ] Run *bumpversion*.
+- [ ] Run *bump-my-version*.
 - [ ] Run `cargo check`
 - [ ] Run `cargo update`
 - [ ] Run `cargo bundle-licenses --format yaml --output THIRDPARTY.yaml`
 - [ ] Check for new or duplicate contributors since the last release:
   `comm -13 (git log $(git describe --tags --abbrev=0) --format="%aN <%aE>" | sort | uniq | psub) (git log --format="%aN <%aE>" | sort | uniq | psub)`.
   Add entries to `.mailmap` to remove duplicates.
-- [ ] Add release date and highlights to release notes.
+- [ ] Add highlights to release notes.
 - [ ] Check readthedocs build, especially release notes formatting.
 - [ ] Tag and push.
 - [ ] Update conda-forge recipe.
diff --git a/doc/src/launchers/built-in.md b/doc/src/launchers/built-in.md
@@ -1,15 +1,33 @@
 # Built-in launchers
 
-**Row** includes built-in support for OpenMP and MPI via the launchers `"openmp"`
-and `"mpi"`. These have been tested on the [built-in clusters](../clusters/built-in.md).
-You may need to add new configurations for your specific cluster or adjust the `none`
-launcher to match your system. Execute [`row show launchers`](../row/show/launchers.md)
-to see the current launcher configuration.
+**Row** includes built-in support for MPI, OpenMP, and Rayon via the launchers
+`"mpi"`, `"openmp"`, and `"rayon"`. These have been tested on the [built-in
+clusters](../clusters/built-in.md). You may need to add new configurations
+for your specific cluster or adjust the `none` launcher to match your system.
+Execute [`row show launchers`](../row/show/launchers.md) to see the current
+launcher configuration.
+
+## OpenMP
+
+Set `launchers = ["openmp"]` to prefix the action's command with:
+```bash
+OMP_NUM_THREADS={T}
+```
+where `{T}` is the number of `threads_per_process` requested.
+
+## Rayon
+
+Set `launchers = ["rayon"]` to prefix the action's command with:
+```bash
+RAYON_NUM_THREADS={T}
+```
+where `{T}` is the number of `threads_per_process` requested.
+
 
 ## Hybrid OpenMP/MPI
 
 When using OpenMP/MPI hybrid applications, place `"openmp"` first in the list of
 launchers (`launchers = ["openmp", "mpi"]`) to generate the appropriate command:
 ```bash
-OMP_NUM_THREADS=T srun --ntasks=N --cpus-per-task=T command $directory
+OMP_NUM_THREADS={T} srun --ntasks=N --cpus-per-task=T command $directory
 ```
diff --git a/doc/src/release-notes.md b/doc/src/release-notes.md
@@ -1,6 +1,10 @@
 # Release notes
 
-## 0.7.1 (2025-11-09)
+## Next release
+
+*Added:*
+
+* Rayon launcher that prefixes commands with `RAYON_NUM_THREADS={T}`.
 
 *Fixed:*
 

diff --git a/src/builtin.rs b/src/builtin.rs
@@ -28,6 +28,17 @@ impl BuiltIn for launcher::Configuration {
 
         result.launchers.insert("openmp".into(), openmp);
 
+        let mut rayon = HashMap::with_capacity(1);
+        rayon.insert(
+            "default".into(),
+            Launcher {
+                threads_per_process: Some("RAYON_NUM_THREADS=".into()),
+                ..Launcher::default()
+            },
+        );
+
+        result.launchers.insert("rayon".into(), rayon);
+
         let mut mpi = HashMap::with_capacity(3);
         mpi.insert(
             "default".into(),

diff --git a/src/launcher.rs b/src/launcher.rs
@@ -256,6 +256,26 @@ mod tests {
         assert_eq!(openmp.prefix(&threads, 1), "OMP_NUM_THREADS=5 ");
     }
 
+    #[test]
+    #[parallel]
+    fn rayon_prefix() {
+        setup();
+        let launchers = Configuration::built_in();
+        let launchers_by_cluster = launchers.by_cluster("any_cluster");
+        let rayon = launchers_by_cluster.get("rayon").expect("a valid Launcher");
+
+        let no_threads = Resources::default();
+        assert_eq!(rayon.prefix(&no_threads, 10), "");
+        assert_eq!(rayon.prefix(&no_threads, 1), "");
+
+        let threads = Resources {
+            threads_per_process: Some(5),
+            ..Resources::default()
+        };
+        assert_eq!(rayon.prefix(&threads, 10), "RAYON_NUM_THREADS=5 ");
+        assert_eq!(rayon.prefix(&threads, 1), "RAYON_NUM_THREADS=5 ");
+    }
+
     #[test]
     #[parallel]
     fn mpi_prefix_none() {
@@ -375,9 +395,10 @@ executable = "e"
         let launchers = Configuration::open_from_path(temp.path().into()).expect("valid launcher");
 
         let built_in = Configuration::built_in();
-        assert_eq!(launchers.launchers.len(), 3);
+        assert_eq!(launchers.launchers.len(), 4);
         assert_eq!(launchers.launchers["openmp"], built_in.launchers["openmp"]);
         assert_eq!(launchers.launchers["mpi"], built_in.launchers["mpi"]);
+        assert_eq!(launchers.launchers["rayon"], built_in.launchers["rayon"]);
 
         let launchers_by_cluster = launchers.by_cluster("non_default");
         let non_default = launchers_by_cluster.get("new_launcher").unwrap();

diff --git a/src/scheduler/bash.rs b/src/scheduler/bash.rs
@@ -643,6 +643,29 @@ mod tests {
         assert!(script.contains("OMP_NUM_THREADS=4 command \"${directories[@]}\""));
     }
 
+    #[test]
+    #[parallel]
+    fn execution_rayon() {
+        let (mut action, directories, launchers) = setup();
+        action.resources.processes = Some(Processes::PerSubmission(1));
+        action.launchers = Some(vec!["rayon".into()]);
+        action.command = Some("command {directories}".to_string());
+
+        let script = BashScriptBuilder::new(
+            "cluster",
+            &action,
+            &directories,
+            &PathBuf::default(),
+            &HashMap::new(),
+            &launchers,
+        )
+        .build()
+        .expect("Valid script.");
+        println!("{script}");
+
+        assert!(script.contains("RAYON_NUM_THREADS=4 command \"${directories[@]}\""));
+    }
+
     #[test]
     #[parallel]
     fn execution_mpi() {

diff --git a/tests/cli.rs b/tests/cli.rs
@@ -791,7 +791,8 @@ fn show_launchers_short() -> Result<(), Box<dyn std::error::Error>> {
         .assert()
         .success()
         .stdout(predicate::str::contains("mpi"))
-        .stdout(predicate::str::contains("openmp\n"));
+        .stdout(predicate::str::contains("openmp\n"))
+        .stdout(predicate::str::contains("rayon\n"));
 
     Ok(())
 }