# Multi-Language

## Multilanguage Interops: Caesar SDKs and APIs

The Caesar framework is not limited to direct Julia use.

Note

2021Q4, Coming Soon! A new multilanguage SDK is under development and will replace and consolidate the previous methods listed below.

### Static, Shared Object .so Compilation

See the Compiling Binaries.

### ROS Integration

Yes, see ROS Integration.

### Previous Generation APIs

The following Github projects provide access to features of Caesar in their language:

• Julia Web interface:

• ZMQ Interface

• C/C++:
• Python:

## ZMQ Messaging Interface

Caesar.jl has a ZMQ messaging interface (interested can see code here) that allows users to interact with the solver code base in a variety of ways. The messaging interface is not meant to replace static .so library file compilation–see below–-but rather provide a more versatile and flexible development strategy.

The current known interface implementations to Caesar.jl are:

### Starting the Caesar ZMQ Navigation Server

Start the Caesar.ZmqCaesar server in a Julia session with a few process cores and full optimization:

julia -p4 -O3

Then run the following commands, and note these steps have also been scripted here:

#import the required modules
using Caesar, Caesar.ZmqCaesar

# create empty factor graph and config objects
fg = initfg()
config = Dict{String, String}()
zmqConfig = ZmqServer(fg, config, true, "tcp://*:5555");

# Start the server over ZMQ
start(zmqConfig)

# give the server a minute to start up ...

The current tests are a good place to see some examples of the current interfacing functions. Feel free to change the ZMQ interface for to any of the ZMQ supported modes of data transport, such as Interprocess Communication (IPC) vs. TCP.

TODO: expand the ZMQ documentation

## Alternative Methods

Interfacing from languages like Python may also be achieved using PyCall.jl although little work has been done in the Caesar.jl framework to explore this path. Julia is itself interactive/dynamic and has plenty of line-by-line and Integrated Development Environment support – consider trying Julia for your application.