Always specify compiler versions and use fewer jobs on CircleCI

Author: ckhroulev

.circleci/config.yml

@@ -304,46 +304,46 @@ workflows:
       - build:
           version: default
           name: old-petsc
-          cc: clang
-          cxx: clang++
+          cc: clang-18
+          cxx: clang++-18
           cmake_prefix: /usr
           petsc_dir: /home/builder/local/petsc-3.7.0
           python: "No"
 
       - build:
           version: default
           name: petsc-64bit
-          cc: clang
-          cxx: clang++
+          cc: clang-18
+          cxx: clang++-18
           cmake_prefix: /usr
           petsc_dir: /home/builder/local/petsc-64bit
           python: "Yes"
 
       - build:
           version: default
           name: old-cmake
-          cc: clang
-          cxx: clang++
+          cc: clang-18
+          cxx: clang++-18
           cmake_prefix: /home/builder/local/cmake-3.16.0
           petsc_dir: /home/builder/local/petsc
           python: "Yes"
 
       - build-minimal:
           name: gcc-minimal
-          cc: gcc
-          cxx: g++
+          cc: gcc-14
+          cxx: g++-14
           cmake_prefix: /usr
 
       - build-minimal:
           name: clang-minimal
-          cc: clang
-          cxx: clang++
+          cc: clang-18
+          cxx: clang++-18
           cmake_prefix: /usr
 
       - build-minimal:
           name: old-cmake-minimal
-          cc: clang
-          cxx: clang++
+          cc: clang-18
+          cxx: clang++-18
           cmake_prefix: /home/builder/local/cmake-3.16.0
 
       - manual-html

docker/ubuntu-ci/build.sh

@@ -7,7 +7,7 @@ set -u
 # Uses environment variables CC and CXX to select the compiler
 
 # Compile using this many jobs
-N=${N:-8}
+N=${N:-4}
 
 # CMake installation prefix
 cmake_prefix=${cmake_prefix:-/usr}