PWPP

Official Resources

• Homepage: https://github.com/hpjeonGIT/PWPP
• Source Repository: https://github.com/hpjeonGIT/PWPP
• Documentation: https://github.com/hpjeonGIT/PWPP
• License: Not specified (open-source, use at your own risk)

Overview

PWPP is a plane-wave basis density functional theory (DFT) code that uses Goedecker-Teter-Hutter (GTH) pseudopotentials. It is a lightweight, educational/research implementation aimed at demonstrating the core algorithms of plane-wave pseudopotential DFT calculations. The code provides a working framework for understanding how electronic structure calculations are performed using the plane-wave formalism.

A Julia port of the code (jpwpp-julia) also exists, demonstrating how to implement a working plane-wave pseudopotential-based DFT simulation program in Julia. The Fortran-based original serves as a reference implementation for the core DFT algorithms.

Scientific domain: Electronic structure theory, density functional theory
Target user community: Researchers and students learning plane-wave DFT methods

Theoretical Methods

• Kohn-Sham density functional theory
• Plane-wave basis set expansion
• Goedecker-Teter-Hutter (GTH) pseudopotentials
• Self-consistent field (SCF) iterations
• Fast Fourier transform (FFT) for grid operations

Capabilities (CRITICAL)

• Plane-wave basis DFT calculations
• GTH pseudopotential support
• Self-consistent field convergence
• Basic electronic structure computations
• Simple, readable codebase suitable for learning

Inputs & Outputs

Input formats:

• Input configuration files specifying atomic positions
• GTH pseudopotential files
• Plane-wave cutoff and k-point parameters

Output data types:

• Total energies
• Kohn-Sham eigenvalues
• Charge densities

Interfaces & Ecosystem

• Programming language: Fortran (original), Julia (port)
• Parallel computing: Limited/none in base implementation
• Dependencies: Standard numerical libraries (BLAS, FFTW or equivalent)

Limitations & Known Constraints

• Author notes the code "may have bugs" and is provided "at your own risk"
• Limited functionality compared to production codes
• Not optimized for large-scale production calculations
• Sparse documentation

Performance Characteristics

• Single-processor or limited parallelization
• Suitable for small systems and benchmarking
• Not optimized for high-performance computing environments

Comparison with Other Codes

• vs Quantum ESPRESSO: PWPP is a minimal educational code; QE is a full-featured production suite
• vs ABINIT: ABINIT offers extensive functionality and parallelization; PWPP focuses on core algorithms
• vs miniPWPP: Both serve as bare-bones testbed codes, but miniPWPP has more structured module support

Best Practices

• Use for learning and understanding plane-wave DFT algorithms
• Verify results against known benchmarks
• Not recommended for production scientific work without extensive testing
• Consider the Julia port for modern language integration

Verification & Sources

Primary sources:

1. GitHub repository: https://github.com/hpjeonGIT/PWPP
2. Julia port: https://github.com/dftworks/jpwpp-julia

Confidence: VERIFIED - GitHub repository confirmed accessible with source code available