Examples catalog

Executables are built when OpenPFC_BUILD_EXAMPLES=ON (default). Output directory is typically <build>/examples/ (exact path depends on the CMake generator and multi-config toolchains).

Prerequisites: Most examples need MPI and a working HeFFTe-linked OpenPFC build. Run with at least mpirun -n 1 unless the source states otherwise.

This page is for lookup and for choosing the next small executable to read. If you want a guided first run, use ../start_here_15_minutes.md. If you want the examples in a teaching sequence with more context, use ../tutorials/spectral_examples_sequence.md. The catalog below stays compact so it can answer “what is this target for?” without becoming another tutorial.

Curriculum (suggested order)

Use the first tier on your first day, then branch by topic. The names are numbered because the source files are intended to be read in roughly that order, not because every user must run every target.

        flowchart LR
  subgraph t1 [Tier 1 — core stack]
    A[02_domain_decomposition]
    B[03_parallel_fft]
    C[05_simulator]
    D[12_cahn_hilliard]
  end
  subgraph t2 [Tier 2 — App / I/O / IC]
    E[10_ui_register_ic]
    F[11_write_results]
    G[14_custom_field_initializer]
  end
  subgraph t3 [Tier 3 — fields and space]
    H[15_finite_difference_heat]
    I[17_custom_coordinate_system]
    J[18_sobel_edge_detection]
  end
  subgraph t4 [Tier 4 — stepping and tools]
    K[19_explicit_stepper_fd]
    L[20_explicit_stepper_spectral]
    M[fft_backend_benchmark]
  end
  A --> B --> C --> D
  D --> E
  D --> F
  E --> G
  D --> H --> J
  D --> I
  H --> K
  D --> L
  C --> M

Tier

Executables

Focus

1 — Core stack

02_domain_decomposition, 03_parallel_fft, 05_simulator, 12_cahn_hilliard

Domain, HeFFTe FFT, Simulator, spectral model

2 — Wiring

10_ui_register_ic, 11_write_results, 14_custom_field_initializer, diffusion_model_with_custom_initial_condition

Registration, writers, custom initial conditions

3 — Fields and space

15_finite_difference_heat, 17_custom_coordinate_system, 18_sobel_edge_detection

Halos, coordinate interpretation, stencil-like field operations

4 — Stepping and tools

19_explicit_stepper_fd, 20_explicit_stepper_spectral, fft_backend_benchmark, profiling_timer_report

Explicit steppers, backend comparison, profiling

Narrative companion: getting_started/01-basics/README.md. Ordered source examples: api_examples_walkthrough.md.

Full catalog

Executable

Source

What it demonstrates

fft_backend_benchmark

fft_backend_benchmark.cpp

FFT backend benchmarking

02_domain_decomposition

02_domain_decomposition.cpp

Domain, Decomposition, MPI

03_parallel_fft

03_parallel_fft.cpp

Distributed FFT (HeFFTe)

04_diffusion_model

04_diffusion_model.cpp

Simple spectral diffusion Model

05_simulator

05_simulator.cpp

Simulator, Time, FieldModifier

06_multi_index

06_multi_index.cpp

Multi-index utilities

07_array

07_array.cpp

Array helpers

08_discrete_fields

08_discrete_fields.cpp

Discrete field types

09_parallel_fft_high_level

09_parallel_fft_high_level.cpp

Higher-level FFT usage

10_ui_register_ic

10_ui_register_ic.cpp

UI and field-modifier registration patterns

11_write_results

11_write_results.cpp

Writing simulation results

12_cahn_hilliard

12_cahn_hilliard.cpp

Cahn–Hilliard-style spectral workflow

fft_kspace_helpers_example

fft_kspace_helpers_example.cpp

k-space helper functions

mpi_worker

mpi_worker.cpp

MPI worker pattern

mpi_worker_inside_class

mpi_worker_inside_class.cpp

MPI worker encapsulated in a class

mpi_timers

mpi_timers.cpp

MPI timing

profiling_timer_report

profiling_timer_report.cpp

Profiling and timer reporting

time

time.cpp

Time-stepping utilities

write_results

write_results.cpp

Results I/O variant

diffusion_model_with_custom_initial_condition

diffusion_model_with_custom_initial_condition.cpp

Diffusion with a custom initial condition

json_read

json_read.cpp

Standalone nlohmann JSON read; does not link OpenPFC

world_helpers_example

world_helpers_example.cpp

Domain compatibility helpers

14_custom_field_initializer

14_custom_field_initializer.cpp

Custom field initializer

15_finite_difference_heat

15_finite_difference_heat.cpp

Finite-difference heat with separated halos; see halo_exchange.md

16_strong_types_demo

16_strong_types_demo.cpp

Strongly typed domain inputs

17_custom_coordinate_system

17_custom_coordinate_system.cpp

Custom coordinate setup

18_sobel_edge_detection

18_sobel_edge_detection.cpp

Sobel-style field operations and edge detection

world_strong_types_example

world_strong_types_example.cpp

Strong types with Domain compatibility helpers

19_explicit_stepper_fd

19_explicit_stepper_fd.cpp

Explicit stepping with finite-difference operators

20_explicit_stepper_spectral

20_explicit_stepper_spectral.cpp

Explicit stepping with spectral operators

Sources not built by default

examples/01_hello_world/world.cpp is used as a tutorial source; the matching add_executable in examples/CMakeLists.txt is commented out. Other .cpp files may exist under examples/ without a CMake target—check examples/CMakeLists.txt for the authoritative list.

See also