gtsam/wrap/README.md

# WRAP

The wrap library wraps the GTSAM library into a Python library or MATLAB toolbox.
It was designed to be more general than just wrapping GTSAM. For notes on creating a wrap interface, see `gtsam.h` for what features can be wrapped into a toolbox, as well as the current state of the toolbox for GTSAM.

## Prerequisites

`Pybind11` and `pyparsing`

1. This library uses `pybind11`, which is included as a subdirectory in GTSAM.
2. The `interface_parser.py` in this library uses `pyparsing` to parse the interface file `gtsam.h`. Please install it first in your current Python environment before attempting the build.

```sh
python3 -m pip install pyparsing
```

## Getting Started

Clone this repository to your local machine and perform the standard CMake install:

```sh
mkdir build && cd build
cmake ..
make install # use sudo if needed
```

Using `wrap` in your project is straightforward from here. In your `CMakeLists.txt` file, you just need to add the following:

```cmake
find_package(gtwrap)

pybind_wrap(${PROJECT_NAME}_py # target
            ${PROJECT_SOURCE_DIR}/cpp/${PROJECT_NAME}.h # interface header file
            "${PROJECT_NAME}.cpp" # the generated cpp
            "${PROJECT_NAME}" # module_name
            "${PROJECT_MODULE_NAME}" # top namespace in the cpp file e.g. gtsam
            "${ignore}" # ignore classes
            ${PROJECT_BINARY_DIR}/${PROJECT_NAME}.tpl # the wrapping template file
            ${PROJECT_NAME} # libs
            "${PROJECT_NAME}" # dependencies
            ON # use boost
            )
```

For more information, please follow our [tutorial](https://github.com/borglab/gtsam-project-python).

## Documentation

Documentation for wrapping C++ code can be found [here](https://github.com/borglab/wrap/blob/master/DOCS.md).

## Python Wrapper

**WARNING: On macOS, you have to statically build GTSAM to use the wrapper.**

1. Set `GTSAM_BUILD_PYTHON=ON` while configuring the build with `cmake`.
1. What you can do in the `build` folder:

   1. Just run python then import GTSAM and play around:

      ```python
      import gtsam
      gtsam.__dir__()
      ```

   1. Run the unittests:
      ```sh
      python -m unittest discover
      ```
   1. Edit the unittests in `python/gtsam/*.py` and simply rerun the test.
      They were symlinked to `<build_folder>/gtsam/*.py` to facilitate fast development.
      `python -m unittest gtsam/tests/test_Pose3.py` - NOTE: You might need to re-run `cmake ..` if files are deleted or added.

1. Do `make install` and `cd <gtsam_install_folder>/python`. Here, you can:
   1. Run the unittests:
      ```sh
      python setup.py test
      ```
   2. Install `gtsam` to your current Python environment.
      ```sh
      python setup.py install
      ```
      - NOTE: It's a good idea to create a virtual environment otherwise it will be installed in your system Python's site-packages.

## Matlab Wrapper

In the CMake, simply include the `MatlabWrap.cmake` file.

```cmake
include(MatlabWrap)
```

This cmake file defines functions for generating MATLAB wrappers.

- `wrap_and_install_library(interfaceHeader linkLibraries extraIncludeDirs extraMexFlags)` Generates wrap code and compiles the wrapper.

Usage example:

    `wrap_and_install_library("lba.h" "" "" "")`

Arguments:

- `interfaceHeader`: The relative or absolute path to the wrapper interface definition file.
- `linkLibraries`: Any _additional_ libraries to link. Your project library
  (e.g. `lba`), libraries it depends on, and any necessary
  MATLAB libraries will be linked automatically. So normally,
  leave this empty.
- `extraIncludeDirs`: Any _additional_ include paths required by dependent
  libraries that have not already been added by
  include_directories. Again, normally, leave this empty.
- `extraMexFlags`: Any _additional_ flags to pass to the compiler when building
  the wrap code. Normally, leave this empty.