gemma.cpp/examples/hello_world
Jan Wassenberg 3ed403e287 Major cleanup of profiler zones, add Caller annotation for all pool.Run
Pass ThreadingContext instead of Pools/Profiler individually, for access to Zones
Add GCPP_ZONE helper
Add Caller argument to pool.Run to enable new stats
Remove most direct dependencies on ThreadPool, prefer ParallelFor

PiperOrigin-RevId: 822934530
2025-10-23 01:54:24 -07:00
..
build [WIP] decouple GemmaImpl from CLI args 2024-03-06 15:06:41 -05:00
BUILD.bazel Automated Code Change 2025-08-01 13:29:50 -07:00
CMakeLists.txt Major cleanup of profiler zones, add Caller annotation for all pool.Run 2025-10-23 01:54:24 -07:00
README.md Update run.cc, CMakeLists and README for incompatible code, dependency changes and argument updates 2025-07-31 00:59:16 +08:00
run.cc Replace mt19937 with new generator to enable parallel sampling 2025-09-04 23:49:10 -07:00

README.md

Hello World Example

This is a minimal/template project for using gemma.cpp as a library. Instead of an interactive interface, it sets up the model state and generates text for a single hard coded prompt.

Build steps are similar to the main gemma executable. For now only cmake/make is available for builds (PRs welcome for other build options).

First use cmake to configure the project, starting from the hello_world example directory (gemma.cpp/examples/hello_world):

cmake -B build

This sets up a build configuration in gemma.cpp/examples/hello_world/build. Note that this fetches libgemma from a git commit hash on github. Alternatively if you want to build using the local version of gemma.cpp use:

cmake -B build -DBUILD_MODE=local

Make sure you delete the contents of the build directory before changing configurations.

Then use make to build the project:

cd build
make hello_world

As with the top-level gemma.cpp project you can use the make commands -j flag to use parallel threads for faster builds.

From inside the gemma.cpp/examples/hello_world/build directory, there should be a hello_world executable. You can run it with the same 3 model arguments as gemma.cpp specifying the tokenizer, compressed weights file, and model type, for example:

./hello_world --tokenizer tokenizer.spm --weights 2b-it-sfp.sbs --model 2b-it

Should print a greeting to the terminal:

"Hello, world! It's a pleasure to greet you all. May your day be filled with joy, peace, and all the things that make your heart soar.

For a demonstration of constrained decoding, add the --reject flag followed by a list of token IDs (note that it must be the last flag, since it consumes every subsequent argument). For example, to reject variations of the word "greeting", run:

./hello_world [...] --reject 32338 42360 78107 106837 132832 143859 154230 190205