GSoC 2025 · GNU Radio 4.0 Block-Set Expansion

Week-3 check-in (mentor — Josh Morman)

   
Date 29 May 2025, 17:00 IST
Duration 30 min
Participants Josh Morman · Krish Gupta

1 · Progress update

  • Math block
    • 75% of MATH headers were ported and are now compiling/building under GR-4 (AddConst, SubtractConst, MultiplyConst, DivideConst, Add, Subtract, Multiply, Divide, Max, Min, And, Or, Xor, Negate, Not, Abs, Integrate, Argmax. ).
    • Conjugate & Log raised type/std::simd edge cases ⇒ plan is to split out a dedicated Conjugate.hpp that wraps both the scalar and SIMD/complex specialisations.
    • Unit tests (qa_math.cpp) extended to cover zero-input, NaN/Inf, and extreme-range values.
  • Structure goal
    • Keep one umbrella header (math.hpp) where practical; spin off a separate file only when template specialisation gets messy (e.g., Conjugate).

2 · OOT module bootstrap

We clarified how the gr-incubator out-of-tree module will be wired into the GNURadio workspace:

# CMakeLists.txt (top of gr-incubator)
cmake_minimum_required(VERSION 3.20)
project(gr4_incubator LANGUAGES CXX)

# 1. Prevent GR4 from building its own tests/benchmarks
set(BUILD_TESTING OFF CACHE BOOL "" FORCE)
set(GR4_ENABLE_BENCHMARKS OFF CACHE BOOL "" FORCE)

# 2. Bring GR4 headers in, but don't compile its sources
add_subdirectory(gnuradio4 EXCLUDE_FROM_ALL)

# 3. Header-only interface target for includes
add_library(gr4_headers INTERFACE)
target_include_directories(gr4_headers INTERFACE
    ${CMAKE_CURRENT_SOURCE_DIR}/gnuradio4/include
    ${CMAKE_CURRENT_SOURCE_DIR}/gnuradio4           # for <gnuradio4/...>
)

# 4. Your actual blocks live in /lib
add_subdirectory(lib)
Use `target_link_libraries(my_block PRIVATE gr4_headers)` inside `lib/CMakeLists.txt`.

Josh will adjust the skeleton so this drops in cleanly.

3 · Naming & build notes

  • Block names stay PascalCase (Conjugate, Log10).
  • File names stay underscore-free – Conjugate.hpp, not conjugate.hpp.
  • Ralph’s multi-header-in-one-file style is fine unless readability suffers;
    Conjugate.hpp will be the first stand-alone exception.
  • Add SIMD guards to keep older toolchains happy:
    #if defined(__cpp_lib_simd) … #endif.

4 · Action items

Owner Task
Krish • Finish SIMD kernel for Conjugate block.
• Extend edge-case tests for Log.
• Draft “Porting 101” doc for newcomers.
Josh • Commit initial gr-incubator CMake scaffold.
• Ping Ralph for doc-progress confirmation.

Next sync: early next week, once the CMake skeleton lands and SIMD builds succeed on GCC 14 & Clang 17.