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Jelly Bean World

A framework for experimenting with never-ending learning. If you use this framework in your research, please cite as:

  title         = {{Jelly Bean World: A Testbed for Never-Ending Learning}},
  author        = {Emmanouil Antonios Platanios and Abulhair Saparov and Tom Mitchell},
  booktitle     = {International Conference on Learning Representations (ICLR)},
  url           = {},
  year          = {2020},

This file is split in multiple sections:

  • Requirements: Describes the prerequisite software that needs to be installed before you can use the Jelly Bean World.
  • Using Swift: Describes how to setup and use our Swift API, and how to reproduce the experiments as detailed in our paper.
  • Using Python: Describes how to setup and use our Python API.
  • Using C++: Describes how to setup and use our C++ API, and how to run the greedy agent as detailed in our paper.
  • Using the Visualizer: Describes how to use build and use the Vulkan-based visualizer.
  • Design: Provides a brief description of the Jelly Bean World design. More information can found in our paper.
  • Troubleshooting: Discusses common issues.


  • GCC 4.9+, Clang 5+, or Visual C++ 14+
  • Python API:
    • Python 2.7 or 3.5+
    • Numpy
  • Swift API:
    • Swift for TensorFlow 0.8 toolchain
  • Visualizer:
    • Vulkan
    • GLFW
    • Make (for Mac or Linux), or Visual Studio 2017+ (for Windows)

Using Swift

Running Experiments

Assuming you have the Swift for TensorFlow 0.8 toolchain installed in your system, you can run Jelly Bean World experiments using commands like the following:

swift run -c release JellyBeanWorldExperiments run \
  --reward collectJellyBeans \
  --agent ppo \
  --observation vision \
  --network plain

Specifically, to reproduce the results presented in our paper you can use the scripts located in the scripts/experiments directory. A good way to start using the Swift API is to play around by modifying these scripts and observing how the results change.

Files that aggregate the experiments results will be generated in the temp/results directory.

After running Swift experiments using the aforementioned command, you can plot the experiment results using commands like the following:

swift run -c release JellyBeanWorldExperiments plot \
  --reward collectJellyBeans \
  --agent ppo

The plots will (by default) be generated in the temp/results directory.

Using the Swift API directly

Using the Jelly Bean World Swift API typically consists of the following steps:

  1. Create a simulator configuration. This configuration contains information about the types of items that exist and their distribution, as well as about the mechanics of the environment (e.g., vision and scent dimensionality, allowed agent actions, etc.). You can also create multiple configurations, which will allow you to concurrently run multiple instances of the Jelly Bean World simulator.
  2. Create a reward schedule. This schedule defines the reward function that will be used at each point in time. Our library already provides some pre-existing reward schedules that you can use, but you should feel free to create new ones. The reward schedules that we used for our paper can be found in the experiments module.
  3. Create a Jelly Bean World environment.
  4. Create an agent. We do not impose any constraints on how you design your agents. They will be the ones interacting with the environment in a similar manner how agents interact with OpenAI Gym environments. Specifically, the agents mainly interact with the environment through the environment step function.

A good reference point for starting is the the experiments module. that we built and used to run all experiments that were presented in our paper.

Using Python

Installation Instructions

Assuming that you have Python installed in your system and that you are located in the root directory of this repository, run the following commands:

git submodule update --init --recursive
cd api/python
python install

Note that if you plan to use this framework with OpenAI gym you should also install gym using pip install gym.


We first present a typical workflow in Python, without using OpenAI gym and we then show how to use this framework within OpenAI gym.

The typical workflow is as follows:

  1. Extend the Agent class to implement custom agents.
  2. Create a Simulator object.
  3. Construct agent instances in this simulator.
  4. Issue action commands for each agent.

The following is a simple example where a simulator is constructed locally (within the same process) and a single agent continuously moves forward. Note that the agent's decision-making logic goes in the do_next_action method.

import jbw
from math import pi

class SimpleAgent(jbw.Agent):
  def __init__(self, simulator, load_filepath=None):
    super(SimpleAgent, self).__init__(simulator, load_filepath)

  def do_next_action(self):

  def save(self, filepath):

  def _load(self, filepath):

# specify the item types
items = []
items.append(jbw.Item("banana", [1.0, 1.0, 0.0], [1.0, 1.0, 0.0], [0], [0], False, 0.0,
        intensity_fn=jbw.IntensityFunction.CONSTANT, intensity_fn_args=[-2.0],
        interaction_fns=[[jbw.InteractionFunction.PIECEWISE_BOX, 40.0, 200.0, 0.0, -40.0]]))

# construct the simulator configuration
config = jbw.SimulatorConfig(max_steps_per_movement=1, vision_range=1,
  allowed_movement_directions=[jbw.ActionPolicy.ALLOWED, jbw.ActionPolicy.DISALLOWED, jbw.ActionPolicy.DISALLOWED, jbw.ActionPolicy.DISALLOWED],
  allowed_turn_directions=[jbw.ActionPolicy.DISALLOWED, jbw.ActionPolicy.DISALLOWED, jbw.ActionPolicy.ALLOWED, jbw.ActionPolicy.ALLOWED],
  no_op_allowed=False, patch_size=32, mcmc_num_iter=4000, items=items, agent_color=[0.0, 0.0, 1.0],
  collision_policy=jbw.MovementConflictPolicy.FIRST_COME_FIRST_SERVED, agent_field_of_view=2*pi,
  decay_param=0.4, diffusion_param=0.14, deleted_item_lifetime=2000)

# create a local simulator
sim = jbw.Simulator(sim_config=config)

# add one agent to the simulation
agent = SimpleAgent(sim)

# start the main loop
for t in range(10000):

See api/python/test/ for an example with more types of items as well as a visualization using the MapVisualizer class.

It is straightforward to create the simulator in server mode, where other clients can connect to it:

sim = jbw.Simulator(sim_config=config, is_server=True, default_client_permissions=jbw.GRANT_ALL_PERMISSIONS)

To connect to existing server (i.e. create the simulator in client mode), for example running on localhost:

sim = jbw.Simulator(server_address="localhost")

See api/python/test/ and api/python/test/ for an example of simulators running in server and client modes (using MPI to communicate).

Using with OpenAI Gym

We also provide a JBW environment for OpenAI gym, which is implemented in api/python/src/jbw/

The action space consists of three actions:

  • 0: Move forward.
  • 1: Turn left.
  • 2: Turn right.

The observation space consists of a dictionary:

  • scent: Vector with shape [S], where S is the scent dimensionality.
  • vision: Matrix with shape [2R+1, 2R+1, V], where R is the vision range and V is the vision/color dimensionality.
  • moved: Binary value indicating whether the last action resulted in the agent moving.

After installing the jbw framework and gym, the provided environment can be used as follows:

import gym
import jbw

# Use 'JBW-render-v0' to include rendering support.
# Otherwise, use 'JBW-v0', which should be much faster.
env = gym.make('JBW-render-v0')

# The created environment can then be used as any other 
# OpenAI gym environment. For example:
for t in range(10000):
  # Render the current environment.
  # Sample a random action.
  action = env.action_space.sample()
  # Run a simulation step using the sampled action.
  observation, reward, _, _ = env.step(action)

Environments with different configurations can be registered as shown in api/python/src/jbw/ and used as shown above.

Agent class

Agents have a very simple interface. They have an abstract do_next_action method which should contain the decision-making logic of the agent and call methods such as self.move or self.turn to perform the next action. The Agent class has an abstract save method that users can implement to save the state of an agent to a file. save is called by Simulator whenever the simulator is saved. The Agent class also has an abstract _load method which is called by the Agent constructor to load the agent's state from a given filepath.

Agents also have a private fields that store state information, such as the agent's position, direction, current scent perception, current visual perception, etc.

Using C++

The typical workflow is as follows:

  1. Create a Simulator object.
  2. Add agents to this simulator.
  3. Issue action commands for each agent.

The following is a simple example where a simulator is constructed locally (within the same process) and a single agent continuously moves forward.

#include <jbw/network.h>
#include <jbw/simulator.h>

using namespace jbw;

/** A helper function to set interaction function parameters. */
inline void set_interaction_args(
    item_properties* item_types, unsigned int first_item_type,
    unsigned int second_item_type, interaction_function interaction,
    std::initializer_list<float> args)
  item_types[first_item_type].interaction_fns[second_item_type].fn = interaction;
  item_types[first_item_type].interaction_fns[second_item_type].arg_count = (unsigned int) args.size();
  item_types[first_item_type].interaction_fns[second_item_type].args = (float*) malloc(max((size_t) 1, sizeof(float) * args.size()));

  unsigned int counter = 0;
  for (auto i = args.begin(); i != args.end(); i++)
    item_types[first_item_type].interaction_fns[second_item_type].args[counter++] = *i;

void on_step(simulator<empty_data>* sim, const hash_map<uint64_t, agent_state*>& agents, uint64_t time) { }

int main(int argc, const char** argv) {
  /* construct the simulator configuration */
  simulator_config config;
  config.max_steps_per_movement = 1;
  config.scent_dimension = 3;
  config.color_dimension = 3;
  config.vision_range = 10;
  for (unsigned int i = 0; i < (size_t) direction::COUNT; i++)
    config.allowed_movement_directions[i] = action_policy::ALLOWED;
  for (unsigned int i = 0; i < (size_t) direction::COUNT; i++)
    config.allowed_rotations[i] = action_policy::ALLOWED;
  config.no_op_allowed = false;
  config.patch_size = 32;
  config.mcmc_iterations = 4000;
  config.agent_field_of_view = 2.09f;
  config.agent_color = (float*) calloc(config.color_dimension, sizeof(float));
  config.agent_color[2] = 1.0f;
  config.collision_policy = movement_conflict_policy::FIRST_COME_FIRST_SERVED;
  config.decay_param = 0.5f;
  config.diffusion_param = 0.12f;
  config.deleted_item_lifetime = 2000;

  /* configure item types */
  config.item_types[0].name = "banana";
  config.item_types[0].scent = (float*) calloc(config.scent_dimension, sizeof(float));
  config.item_types[0].color = (float*) calloc(config.color_dimension, sizeof(float));
  config.item_types[0].required_item_counts = (unsigned int*) calloc(1, sizeof(unsigned int));
  config.item_types[0].required_item_costs = (unsigned int*) calloc(1, sizeof(unsigned int));
  config.item_types[0].scent[0] = 1.0f;
  config.item_types[0].color[0] = 1.0f;
  config.item_types[0].blocks_movement = false;
	config.item_types[0].visual_occlusion = 0.0;
  config.item_types.length = 1;

  /* specify the intensity and interaction function parameters */
  config.item_types[0].intensity_fn.fn = constant_intensity_fn;
  config.item_types[0].intensity_fn.arg_count = 1;
  config.item_types[0].intensity_fn.args = (float*) malloc(sizeof(float) * 1);
  config.item_types[0].intensity_fn.args[0] = -2.0f;
  config.item_types[0].interaction_fns = (energy_function<interaction_function>*)
    malloc(sizeof(energy_function<interaction_function>) * config.item_types.length);
  set_interaction_args(, 0, 0, piecewise_box_interaction_fn, {40.0f, 200.0f, 0.0f, -40.0f});

  /* create a local simulator */
  simulator<empty_data>& sim = *((simulator<empty_data>*) alloca(sizeof(simulator<empty_data>)));
  if (init(sim, config, empty_data()) != status::OK) {
    fprintf(stderr, "ERROR: Unable to initialize simulator.\n");
    return EXIT_FAILURE;

  /* add one agent to the simulation */
  uint64_t new_agent_id; agent_state* new_agent;
  status result = sim.add_agent(new_agent_id, new_agent);
  if (result != status::OK) {
    fprintf(stderr, "ERROR: Unable to add new agent.\n");
    return EXIT_FAILURE;

  /* the main simulation loop */
  for (unsigned int t = 0; t < 10000; t++) {
    if (sim.move(new_agent_id, direction::UP, 1) != status::OK) {
      fprintf(stderr, "ERROR: Unable to move agent.\n");
      return EXIT_FAILURE;

See jbw/tests/simulator_test.cpp for an example with more types of items, as well as a multithreaded example and an MPI example.

To setup an MPI server for a simulator sim, the init_server function in jbw/mpi.h may be used:

  /* NOTE: this blocks during the lifetime of the server */
  sync_server new_server;
  if (!init_server(new_server, sim, 54353, 256, 8, permissions::grant_all())) { /* process error */ }

To set up an asynchronous MPI server (where init_server will not block), the async_server class in jbw/mpi.h is used:

  async_server new_server;
  if (!init_server(new_server, sim, 54353, 256, 8, permissions::grant_all())) { /* process error */ }

To connect to an existing server, for example at localhost:54353, we use the client class defined in jbw/mpi.h:

  client<empty_data> new_client;
  uint64_t client_id;
  uint64_t simulation_time = connect_client(new_client, "localhost", 54353, client_id);
  if (simulation_time == UINT64_MAX) { /* process error */ }

The commands may be sent to the server using the functions send_add_agent, send_move, send_turn, etc. When the client receives responses from the server, the functions on_add_agent, on_move, on_turn, etc will be invoked, which must be defined by the user.

Greedy Agent

The greedy visual agent is implemented in jbw/agents/greedy_visual_agent.cpp.

Compiling on Mac or Linux:

git submodule update --init --recursive
make greedy_visual_agent

The compiled executable will be located in bin/greedy_visual_agent.

Compiling on Windows:

First make sure the submodules are initialized by running git submodule update --init --recursive. Next, build the Visual Studio project in vs/greedy_visual_agent.vcxproj. The compiled executable will be located in bin/greedy_visual_agent.exe.

Feel free to experiment with the environment configuration in jbw/agents/greedy_visual_agent.cpp.

Using the Visualizer

We provide a real-time interactive visualizer, located in jbw/visualizer/jbw_visualizer.cpp, built using Vulkan and GLFW.

Mac or Linux:

git submodule update --init --recursive
make visualizer

The executable will be located in bin/jbw_visualizer. To run the visualizer:

cd bin


First make sure the submodules are initialized by running git submodule update --init --recursive. Next, open the Visual Studio project vs/jbw_visualizer.vcxproj and make sure the include and library paths have the correct Vulkan and GLFW directories on your machine. To do so, in the Solution Explorer, right click on the jbw_visualizer project and select "Properties". Select "C\C++ > General", and modify "Additional Include Directories" as needed. For the library paths, select "Linker > General" and modify "Additional Library Directories" as needed. Then build the project. The executable will be located in bin/jbw_visualizer.exe. To run the visualizer:

cd bin


Running the visualizer without arguments will print the help output, detailing how to use the visualizer. The visualizer connects to a simulation server, as specified by an address command-line argument, and begins to render the connected simulation. The user is able to move the camera in the environment, zoom in and out, increase or decrease the simulation update rate, track agents, and take screenshots. A local simulation can be started without needing to connect to a server by running ./jbw_visualizer --local, which uses a hard-coded configuration in jbw/visualizer/jbw_visualizer.cpp.


The center of our design is the simulator. The simulator handles everything that happens to our artificial environment. It does by controlling the map generation process, as well as the agent-environment interaction. Agents are part of the design too, but in a very limited way. This is intentional, and it is done in order to allow for flexibility in the design of custom agents.


The simulator controls the following things:

  • Incremental map generation, based on the movement of the agents.
  • Passage of time.
  • Allowed agent-environment interactions.

Under the current design:

  • Each simulator owns a set of agents.
  • Users can easily add/register new agents to an existing simulator.
  • Each agent interacts with the simulator by deciding when and where to move.
  • Once all agents have requested to perform an action, the simulator progresses by one time step and notifies invokes a callback function.
  • Some items in the world are automatically collected by the agents. The collected items are available in each agent's state information.

NOTE: Note that the agent is not moved until the simulator advances the time step and issues a notification about that event. The simulator only advances the time step once all agents have requested to act.

We provide a message-passing interface (using TCP) to allow the simulator to run remotely, and agents can issue move commands to the server. In Python, the Simulator can be constructed as a server with the appropriate constructor arguments. If a server address is provided to the Simulator constructor, it will try to connect to the Simulator running at the specified remote address, and all calls to the Simulator class will be issued as commands to the server. In C++, jbw/mpi.h provides the functionality to run the server and clients. See jbw/tests/simulator_test.cpp for an example.


We simulate an infinite map by dividing it into a collection of n x n patches. When agents move around, they may move into new patches. The simulator ensures that when an agent approaches a new patch, that patch is appropriately initialized (if it wasn't previously). When new patches are initialized, we fill them with items.

The items are distributed according to a pairwise interaction point process on the 2-dimensional grid of integers. The probability of a collection of points X = {X_1, X_2, ...} is given by:

    p(X) = c * exp{sum over i of f(X_i) + sum over j of g(X_i, X_j)}.

Here, c is a normalizing constant. f(x) is the intensity function, that controls the likelihood of generating a point at x independent of other points. g(x,y) is the interaction function, which controls the likelihood of generating the point at x given the existence of a point at y. Metropolis-Hastings sampling is used to sample from this distribution.

It is through the interaction function that we can control whether items of one type are "attracted to" or "repelled by" items of another type. We allow the user to specify which intensity/interaction functions they wish to use, for each item.

Vision is implemented straightforwardly: within the visual field of each agent, empty cells are rendered with a single color. Then for each item within the visual field of the agent, we render the corresponding pixel with the color of the item.

Scent is modeled as a simple diffusion system on the grid, where each cell is given a vector of scents (where each dimension can be used to model orthogonal/unrelated scents). More precisely, if S(x,y,t) is the scent at location (x,y) at time t, then

    S(x,y,t+1) = lambda*S(x,y,t) + C(x,y,t+1) + alpha*(S(x-1,y,t) + S(x+1,y,t) + S(x,y-1,t) + S(x,y+1,t)),

where lambda is the rate of decay of the scent at the current location, alpha is the rate of diffusion from neighboring cells, and C(x,y,t) is the scent of any items located at (x,y) at time t (this is zero if there are no items at that position).

Our simulator keeps track of the creation and destruction times of each item in the world, and so the scent can be computed correctly, even as items are created and destroyed (collected) in the world. The simulation ensures the scent (or lack thereof) diffuses correctly.


The core library is implemented in C++ and has no dependencies. It should be able to run on Mac, Linux, and Windows. We already provide Python and Swift APIs that are quite simple to use and extend. APIs for other languages are also easy to implement.


Repository initialization, publickey

If you get the message Permission denied (publickey). when initializing the repository by calling git submodule update --init --recursive make sure you have your public key set correctly in You can see this example to generate a new one.


A framework for experimenting with never-ending learning




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