PARATEC

Official Resources

• Homepage: http://www.nersc.gov/users/software/applications/materials-science/paratec/ (archived)
• Documentation: Available through NERSC archives
• Source Repository: Available to registered users (NERSC)
• License: Free for academic use (registration required)

Overview

PARATEC (PARAllel Total Energy Code) is a parallel plane-wave DFT code developed at Lawrence Berkeley National Laboratory and UC Berkeley. Designed for massively parallel computations on supercomputers, PARATEC pioneered several algorithms for efficient large-scale DFT calculations and was particularly important in the early 2000s for demonstrating petascale computational materials science. While development has slowed, it remains historically significant and is archived at NERSC.

Scientific domain: Plane-wave DFT, parallel computing, materials science
Target user community: HPC researchers, historical reference, large-scale DFT

Theoretical Methods

• Kohn-Sham DFT (LDA, GGA)
• Plane-wave basis with pseudopotentials
• Norm-conserving pseudopotentials
• Born-Oppenheimer molecular dynamics
• Conjugate gradient minimization
• Preconditioned conjugate gradient
• Direct minimization
• Car-Parrinello-like dynamics

Capabilities (CRITICAL)

• Ground state electronic structure
• Total energy calculations
• Forces on atoms
• Geometry optimization
• Molecular dynamics
• Band structure calculations
• Density of states
• Massively parallel (MPI)
• Efficient FFT algorithms
• Large system calculations (1000+ atoms)
• Excellent scalability (demonstrated on 10,000+ processors)
• Stress tensor calculations

Sources: NERSC documentation, historical literature

Key Strengths

Massive Parallelization:

• Pioneering parallel algorithms
• Efficient on thousands of processors
• 3D FFT parallelization
• Load balancing
• HPC optimized

Large Systems:

• 1000+ atoms feasible
• Materials science applications
• Complex systems
• Production calculations

FFT Optimization:

• Efficient 3D FFTs
• Parallel FFT libraries
• Minimized communication
• Optimized algorithms

Historical Significance:

• Early petascale demonstrations
• Algorithm development
• Parallel computing advances
• Materials science milestones

Inputs & Outputs

• Input formats:

  • Text-based input files
  • Atomic coordinates
  • Cell parameters
  • Pseudopotential specifications

• Output data types:

  • Text output files
  • Energies and forces
  • Wavefunction data
  • Charge densities
  • Trajectory files

Interfaces & Ecosystem

• Visualization:

  • Standard tools
  • Custom scripts
  • XCrySDen compatible

• Analysis:

  • Post-processing scripts
  • Property extraction
  • Custom tools

• Parallelization:

  • MPI parallelization
  • Optimized for Cray systems
  • NERSC supercomputers
  • 3D domain decomposition

Workflow and Usage

Typical Input Structure:

• Main input file with parameters
• Atomic coordinates file
• Pseudopotential files
• K-point specifications

Running PARATEC:

mpirun -np 1024 paratec.x < input.in > output.out

NERSC Usage:

• Available on NERSC systems
• Module system
• Job submission scripts
• Queue system integration

Advanced Features

Parallel FFT:

• 3D parallel FFT
• Efficient communication
• Transpose algorithms
• Optimized libraries

Preconditioning:

• Kerker preconditioning
• Conjugate gradient acceleration
• Improved convergence
• Reduced iterations

Load Balancing:

• Dynamic load balancing
• K-point distribution
• Band parallelization
• Processor grid optimization

Large-Scale Calculations:

• Thousand-atom systems
• Production MD runs
• Materials databases
• High-throughput studies

Performance Characteristics

• Scaling: Excellent to 10,000+ processors (historical)
• Speed: Competitive for era
• Efficiency: High parallel efficiency
• Typical systems: 100-2000 atoms
• Memory: Distributed efficiently

Computational Cost

• DFT: Standard plane-wave scaling
• Large systems: Enabled by parallelization
• MD: Feasible for production
• Scaling: Near-linear demonstrated

Limitations & Known Constraints

• Development: Slowed/archived
• Community: Historical, smaller active community
• Features: Fewer than modern codes
• Documentation: Archived
• Platform: Primarily NERSC/Cray systems
• Functionals: Limited to LDA/GGA
• Support: Archived status

Comparison with Other Codes

• vs VASP: PARATEC open (academic), pioneering parallel methods
• vs Quantum ESPRESSO: QE more actively developed
• vs Qbox: Similar goals, different eras
• Historical significance: Pioneered massively parallel DFT

Application Areas

Materials Science:

• Electronic structure
• Large systems
• Complex materials
• Production calculations

HPC Demonstrations:

• Scaling studies
• Petascale computing
• Algorithm development
• Performance benchmarks

Historical Applications:

• Early large-scale DFT
• Materials databases
• Method validation
• Parallel computing research

Best Practices

Parallelization:

• Optimize processor grid
• Balance k-points
• Test scaling efficiency
• Use appropriate decomposition

Convergence:

• Plane-wave cutoff
• K-point sampling
• SCF tolerance
• Preconditioning parameters

Performance:

• Optimize FFT grid
• Balance workload
• Minimize I/O
• Use efficient pseudopotentials

Community and Support

• Archived at NERSC
• Historical documentation
• Academic license
• Limited active support
• Reference implementation

Educational Resources

• NERSC documentation (archived)
• Historical papers
• Algorithm descriptions
• Parallel computing references

Development

• UC Berkeley origins
• LBNL development
• NERSC deployment
• Historical development (active 1990s-2000s)
• Archived status

Historical Significance

Parallel Computing:

• Pioneered massively parallel DFT
• Algorithm development
• Scaling demonstrations
• HPC milestones

Materials Science:

• Large-scale calculations
• Production simulations
• Database generation
• Method validation

Legacy:

• Influenced later codes
• Algorithm contributions
• Parallel computing lessons
• Educational value

Technical Contributions

• Parallel 3D FFT algorithms
• Load balancing strategies
• Preconditioned minimization
• Efficient communication patterns

Verification & Sources

Primary sources:

1. NERSC archive: http://www.nersc.gov/users/software/applications/materials-science/paratec/
2. B. G. Pfrommer et al., J. Comput. Phys. 131, 233 (1997) - PARATEC algorithms
3. Historical NERSC documentation

Secondary sources:

1. Published studies using PARATEC
2. Parallel computing literature
3. Materials science applications
4. NERSC reports and documentation

Confidence: VERIFIED - NERSC archive and literature confirmed

Verification status: ✅ VERIFIED

• NERSC archive: ACCESSIBLE
• Documentation: Archived at NERSC
• Historical status: Confirmed
• Academic citations: >200
• Historical significance: Pioneering parallel DFT code
• Development status: Archived/historical
• Specialized strength: Massively parallel plane-wave DFT, historical importance, algorithm contributions