Remote Build

Remote Build on Bucy (Intel Compiler)

This skill guides you through building MAPL on the bucy remote server using the Intel compiler. Bucy is typically used for Intel-specific builds and testing.

Prerequisites

• SSH access to bucy configured
• MAPL repository cloned locally
• Understanding of basic MAPL build process (see mapl-build skill)

Quick Reference

SSH Connection

ssh bucy

Standard Intel Build on Bucy

# On bucy
cd ~/swdev/VS/MAPL  # or your MAPL path

# Load Intel compiler and dependencies
module purge
module load comp/intel-2021.3.0
module load cmake/3.21.0

# Create and enter build directory
mkdir -p intel
cd intel

# Configure
cmake .. \
  -DCMAKE_Fortran_COMPILER=ifort \
  -DCMAKE_C_COMPILER=icc \
  -DCMAKE_CXX_COMPILER=icpc \
  -DCMAKE_BUILD_TYPE=Debug \
  -DBASEDIR=/discover/swdev/gmao_SIteam/BaseLibs/ESMA-Baselibs-7.17.2/x86_64-pc-linux-gnu/ifort_2021.3.0-intelmpi_2021.3.0

# Build
make -j8 install

Configuration Details

User-Specific Settings

IMPORTANT: Bucy configuration is standardized. All developers use the same module names and paths on bucy.

If you have a ~/.opencode/mapl-config.yaml file with bucy settings, use those. Otherwise, use these standard values:

bucy:
  hostname: "bucy"
  modules:
    - "comp/intel-2021.3.0"
    - "cmake/3.21.0"
  compilers:
    fortran: "ifort"
    c: "icc"
    cxx: "icpc"
  basedir: "/discover/swdev/gmao_SIteam/BaseLibs/ESMA-Baselibs-7.17.2/x86_64-pc-linux-gnu/ifort_2021.3.0-intelmpi_2021.3.0"
  mapl_path: "~/swdev/VS/MAPL"  # Update if your path differs

Module System

CRITICAL: Always start with module purge to avoid conflicts from your default environment.

Standard modules on bucy:

• comp/intel-2021.3.0 - Intel Fortran/C/C++ compilers
• cmake/3.21.0 - CMake build system

Check available modules:

module avail

BaseLibs Path

The BASEDIR must match the Intel compiler version you're using. The standard path is:

/discover/swdev/gmao_SIteam/BaseLibs/ESMA-Baselibs-7.17.2/x86_64-pc-linux-gnu/ifort_2021.3.0-intelmpi_2021.3.0

IMPORTANT: If you're using a different Intel version, adjust the BaseLibs path accordingly.

Step-by-Step Build Process

1. Connect to Bucy

ssh bucy

2. Navigate to MAPL Directory

cd ~/swdev/VS/MAPL  # or wherever your MAPL repo is located

3. Load Modules

module purge
module load comp/intel-2021.3.0
module load cmake/3.21.0

Verify modules loaded:

module list

4. Create Build Directory

mkdir -p intel
cd intel

CRITICAL: Use a dedicated build directory for Intel (e.g., intel). Never mix compilers in the same build directory.

5. Configure with CMake

cmake .. \
  -DCMAKE_Fortran_COMPILER=ifort \
  -DCMAKE_C_COMPILER=icc \
  -DCMAKE_CXX_COMPILER=icpc \
  -DCMAKE_BUILD_TYPE=Debug \
  -DBASEDIR=/discover/swdev/gmao_SIteam/BaseLibs/ESMA-Baselibs-7.17.2/x86_64-pc-linux-gnu/ifort_2021.3.0-intelmpi_2021.3.0

Common CMake Options:

• -DCMAKE_BUILD_TYPE=Debug - Debug build (default for development)
• -DCMAKE_BUILD_TYPE=Release - Optimized build
• -DCMAKE_INSTALL_PREFIX=<path> - Custom install location

6. Build

make -j8 install

Build Performance:

• Intel builds typically take 5-10 minutes
• Adjust -j8 based on available cores and system load
• Use -j4 if system is busy, -j16 if you have priority

7. Verify Build

# Check that libraries were built
ls -lh lib/

# Check that executables were built (if applicable)
ls -lh bin/

Running Tests on Bucy

After building, you can run tests:

# From the build directory (e.g., intel/)
ctest

# Run tests in parallel
ctest -j4

# Run specific test
ctest -R TestName

# Verbose output for debugging
ctest -V -R TestName

See the mapl-testing skill for comprehensive testing guidance.

Common Issues and Solutions

Issue: "Module not found"

Symptom:

module: command not found

Solution: Ensure you're on bucy and your shell is properly configured for modules:

source /usr/share/modules/init/bash  # for bash
source /usr/share/modules/init/tcsh  # for tcsh

Issue: "Compiler not found" after loading modules

Symptom:

CMake Error: CMAKE_Fortran_COMPILER not set

Solution:

1. Verify modules are loaded: module list
2. Check compiler is in PATH: which ifort
3. If not found, reload modules:

   module purge
   module load comp/intel-2021.3.0
   

Issue: "Cannot find BaseLibs"

Symptom:

CMake Error: Could not find ESMF

Solution: Verify BASEDIR path exists and matches your Intel version:

ls /discover/swdev/gmao_SIteam/BaseLibs/ESMA-Baselibs-7.17.2/x86_64-pc-linux-gnu/

Look for directory matching your Intel compiler version (e.g., ifort_2021.3.0-intelmpi_2021.3.0).

Issue: Build fails with "out of memory"

Solution: Reduce parallel jobs:

make -j2 install  # or even -j1 if necessary

Issue: Stale build cache

Symptom: CMake configuration seems wrong or inconsistent.

Solution: Clear CMake cache and rebuild:

rm -rf CMakeCache.txt CMakeFiles/
cmake .. [options]
make -j8 install

Local vs Remote Development Workflow

Typical Workflow Pattern

1. Develop locally with your preferred compiler (NAG recommended for strict checking)
2. Test locally with fast tests
3. Push to feature branch
4. Build on bucy with Intel to verify portability
5. Run full test suite on bucy if needed

Syncing Code to Bucy

Option 1: Git (Recommended)

# Local: commit and push
git add .
git commit -m "Description"
git push

# On bucy: pull changes
ssh bucy
cd ~/swdev/VS/MAPL
git fetch
git checkout your-feature-branch
git pull

Option 2: rsync

# From local machine
rsync -avz --exclude 'build*' --exclude '*.o' \
  ~/swdev/VS/MAPL/ bucy:~/swdev/VS/MAPL/

CRITICAL: Always prefer git workflow. Only use rsync for temporary testing of uncommitted changes.

Intel-Specific Compiler Warnings

Intel compiler may produce different warnings than NAG or gfortran. Common Intel-specific issues:

Uninitialized Variables

Intel is less strict about uninitialized variables. Code that passes Intel may fail NAG.

Best Practice: Always develop with NAG first, then verify with Intel.

Optimization Issues

Intel's aggressive optimization can expose race conditions or undefined behavior.

Solution: If Release build fails but Debug works, try:

cmake .. -DCMAKE_BUILD_TYPE=RelWithDebInfo

OpenMP Issues

Intel has different OpenMP default behaviors.

Solution: Explicitly specify OpenMP flags if needed:

cmake .. -DCMAKE_Fortran_FLAGS="-qopenmp"

Performance Considerations

Build Performance

• Parallel jobs: Intel builds benefit from high parallelism (-j8 or higher)
• Network filesystem: Bucy may use networked home directories; build times depend on I/O
• Local scratch: For faster builds, consider building in /tmp or local scratch space

Test Performance

• Intel-compiled code may have different performance characteristics
• Some tests may be faster or slower than with other compilers
• Numerical results should match within tolerance (see mapl-testing skill)

Related Skills

• mapl-build - General MAPL building guide (NAG, gfortran, Intel locally)
• compiler-switching - How to safely switch between compilers
• mapl-testing - Running and debugging tests
• github-workflow - Git/GitHub workflow for pushing changes before building on bucy

Advanced Topics

Using Different Intel Versions

To use a different Intel compiler version:

1. Check available versions:

   module avail comp/intel
   

2. Load desired version:

   module load comp/intel-<version>
   

3. CRITICAL: Update BASEDIR to match the Intel version in the BaseLibs path.

Building in Custom Location

cmake .. \
  -DCMAKE_INSTALL_PREFIX=/discover/nobackup/$USER/MAPL-intel \
  [other options]

make -j8 install

This installs to a custom location instead of the default install/ directory.

Debugging Build Issues

Enable verbose build output:

make VERBOSE=1 -j8 install

This shows full compiler commands, useful for diagnosing configuration issues.

When to use this skill:

• Building MAPL with Intel compiler
• Verifying compiler portability before PR
• Debugging Intel-specific issues
• Running tests on bucy infrastructure