This guide provides step-by-step instructions for setting up your environment, installing dependencies, cloning the source code, and compiling the PICurv solver.

1. Prerequisites

Before you begin, ensure you have the following software installed on your system. These are essential for building and running the solver.

A C Compiler: Such as GCC or Clang.
An MPI Implementation: Required for parallel computing. Common choices are MPICH or OpenMPI.
Git: For cloning the source code repository.
Make: The standard build automation tool.
PETSc (version 3.20.3 or newer): This is the core dependency. PICurv relies on PETSc for its parallel data structures (DMDA, DMSwarm), linear and nonlinear solvers, and I/O.

2. Installation and Verification of Prerequisites

This section describes how to install the required dependencies.

2.1. Installing Build Tools and MPI

On most Linux distributions, you can install the compiler, Make, and an MPI library using the system's package manager.

For Debian/Ubuntu:

sudo apt-get update

sudo apt-get install build-essential gfortran mpich

For CentOS/RHEL/Fedora:

sudo yum groupinstall "Development Tools"

sudo yum install mpich-devel

For macOS (using Homebrew):

brew install gcc open-mpi

2.2. Installing PETSc

Installing PETSc correctly is the most critical step. We recommend building it from source to ensure all required components are enabled.

Download PETSc: Go to the PETSc website and download a recent version (e.g., 3.20.3). Or, use git: bash git clone -b v3.20.3 https://gitlab.com/petsc/petsc.git cd petsc
Configure PETSc: The PICurv solver specifically requires DMSwarm. We recommend a configuration like the one below. Run this from the petsc directory.

For a debugging build (recommended for development):

bash ./configure --with-cc=mpicc --with-cxx=mpicxx --with-fc=mpif90 \ --download-fblaslapack --download-metis --download-parmetis \ --with-dmswarm=1 \ --with-debugging=1

For an optimized build (recommended for production runs):

bash ./configure --with-cc=mpicc --with-cxx=mpicxx --with-fc=mpif90 \ --download-fblaslapack --download-metis --download-parmetis \ --with-dmswarm=1 \ --with-debugging=0 --COPTFLAGS='-O3 -march=native' --CXXOPTFLAGS='-O3 -march=native' --FOPTFLAGS='-O3 -march=native'
Build and Test PETSc: After configuration is complete, follow the instructions printed to the screen.

```bash make all make check

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2.3. Verifying the PETSc Installation

Once PETSc is built, you must set two environment variables so that other applications (like PICurv) can find it.

Set Environment Variables: Add the following lines to your shell startup file (e.g., ~/.bashrc, ~/.zshrc). bash export PETSC_DIR=/path/to/your/petsc export PETSC_ARCH=arch-linux-c-debug # Or whatever arch was created during configure export PATH="${PETSC_DIR}/${PETSC_ARCH}/bin:${PATH}"

Replace /path/to/your/petsc with the actual path.

Now, source your startup file or open a new terminal:

bash source ~/.bashrc
Confirm the Variables are Set: Run echo $PETSC_DIR and echo $PETSC_ARCH. They should print the paths you just set.

3. Getting the PICurv Code

With all prerequisites in place, you can now clone the PICurv repository.

git clone https://github.com/VishalKandala/PICurv.git

cd PICurv

4. Compiling PICurv

The provided Makefile is designed to automatically find your PETSc installation using the environment variables you set.

Navigate to the Root Directory: Ensure you are in the top-level PICurv/ directory.
Clean Previous Builds (Optional but Recommended): It's good practice to start with a clean slate.

bash make clean_all
Build the Solver and Postprocessor: The Makefile has targets for the main executables.

bash make picsolver # Builds the main CFD/particle solver make postprocessor # Builds the data postprocessor utility

If the compilation is successful, you will find the executables picsolver and postprocessor in the bin/ directory.

Next Steps

Congratulations, you have successfully built the PICurv solver!

You are now ready to run your first simulation. Please proceed to the User Guide for instructions on setting up and running a test case.

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