Visualize

The script visualize.py is used to visualize a search in 1D, 2D or 3D.

Outputs generated by the script are:

• *video.mp4

  a video of the search (.mp4), only for Unix-based systems with ffmpeg installed

• *video_xxxxxxxx.png

  video frames, only if requested or if unable to make a video

Each frame consists of two panels: one shows an observation map with the hits received since the start of the search, the other shows the current probability distribution of source locations.

Parameters of the script are:

• Source-tracking POMDP

  • N_DIMS (int > 0)

    number of space dimensions (1D, 2D, …)

  • LAMBDA_OVER_DX (float >= 1)

    dimensionless problem size

  • R_DT (float > 0.0)

    dimensionless source intensity

  • NORM_POISSON (‘Euclidean’, ‘Manhattan’ or ‘Chebyshev’)

    norm used for hit detections, usually ‘Euclidean’

  • N_HITS (int >= 2 or None)

    number of possible hit values, set automatically if None

  • N_GRID (odd int >= 3 or None)

    linear size of the domain, set automatically if None

• Policy

  • POLICY (int)

    • -1: neural network

    • 0: infotaxis (Vergassola, Villermaux and Shraiman, Nature 2007)

    • 1: space-aware infotaxis

    • 2: custom policy (to be implemented by the user)

    • 5: random walk

    • 6: greedy policy

    • 7: mean distance policy

    • 8: voting policy (Cassandra, Kaelbling & Kurien, IEEE 1996)

    • 9: most likely state policy (Cassandra, Kaelbling & Kurien, IEEE 1996)

  • STEPS_AHEAD (int >= 1)

    number of anticipated moves, can be > 1 only for POLICY=0

  • MODEL_PATH (str or None)

    path of the model (neural network) for POLICY=-1, None otherwise

• Setup

  • DRAW_SOURCE (bool)

    if False, episodes will continue until the source is almost surely found (Bayesian setting)

  • ZERO_HIT (bool)

    whether to enforce a series of zero hits

• Visualization

  • VISU_MODE (int={0,1,2})

    • 0: run without video

    • 1: make video in the background

    • 2: make video with live preview (slower)

    Note: with VISU_MODE = 2, the aspect ratio may be wrong depending on your screen size or resolution.

  • FRAME_RATE (int > 0)

    number of frames per second in the video

  • KEEP_FRAMES (bool)

    whether individual frames should be saved (otherwise frames are deleted, only the video is kept)

• Stopping criteria

  • STOP_p (float ~ 0):

    stops when the probability that the source is found is greater than 1 - STOP_p (only if DRAW_SOURCE is False)

  • STOP_t (int > 0)

    maximum number of steps per episode

• Saving

  • RUN_NAME (str or None)

    prefix used for all output files, if None will use a timestamp