pybop-team#123 add custom script to dynamically generate matrix

.github/workflows/build_matrix.sh

@@ -0,0 +1,41 @@
+#!/bin/bash
+
+# This helper script generates a matrix for further use in the
+# scheduled/nightly builds for PyBOP, i.e., in scheduled_tests.yaml
+# It generates a matrix of all combinations of the following variables:
+# - python_version: 3.8, 3.9, 3.10, 3.11
+# - os: ubuntu-latest, windows-latest, macos-latest
+# - pybamm_version: the last four versions of PyBaMM from PyPI
+
+python_version=("3.8" "3.9" "3.10" "3.11")
+os=("ubuntu-latest" "windows-latest" "macos-latest")
+# This command fetches the last four PyBaMM versions excluding release candidates from PyPI
+pybamm_version=$(curl -s https://pypi.org/pypi/pybamm/json | jq -r '.releases | keys[]' | grep -v rc | tail -n 4 | tr '\n' ' ')
+
+json='{
+  "include": [
+'
+
+# loop through each combination of variables to generate matrix components
+for py_ver in "${python_version[@]}"; do
+  for os_type in "${os[@]}"; do
+    for pybamm_ver in "${pybamm_version[@]}"; do
+      json+='{
+        "os": "'$os_type'",
+        "python_version": "'$py_ver'",
+        "pybamm_version": "'$pybamm_ver'"
+      },'
+    done
+  done
+done
+
+# fix structure, removing trailing comma
+json=${json%,}
+
+# close dict
+json+='
+  ]
+}'
+
+
+echo "$json" | jq .