webplot: an embedded plot server for torch

webplot is light-weight embedded plot server based on waffle and threads. Just require 'webplot' and you are good to go. No server launches required. See examples.

The embedded webplot server is fully controllable as it equipped a task queue for you to give it job asynchronously. See Technical overview to add any web page to the server any where in your script.

Features of webplot:

Launch itself in your script seamlessly. No manual server launches.
Is fully controllable with Lua script
Read tensor in your script without memory copy
Support Websocket for live update

Installation

Install waffle

luarocks install https://raw.githubusercontent.com/benglard/htmlua/master/htmlua-scm-1.rockspec
luarocks install https://raw.githubusercontent.com/benglard/waffle/master/waffle-scm-1.rockspec

Install webplot

luarocks install https://raw.githubusercontent.com/Po-Hsun-Su/webplot/master/webplot-scm-1.rockspec

Examples

Plot sin and cosine using dygraph

local webplot = require 'webplot'
local dygraph = require 'webplot.dygraph'
local sys = require 'sys'

local x = torch.linspace(0,math.pi,100):view(100,1)
local y1 = torch.sin(x)
local y2 = torch.cos(x)
local data = torch.cat({x,y1,y2},2):totable()

local options = {
  labels = {"x", "sin", "cos"}
}
local fig_path = 'figure1/'

dygraph.add(fig_path, data, options) -- add to server
webplot.open(fig_path) -- open the plot in browser

Live update

for i = 100, 400 do
  sys.sleep(0.03)
  x = i*math.pi/100
  data[i] = {x, math.sin(x),math.cos(x)}
  dygraph.append(fig_path, data[i]) -- append data and redraw
end

webplot.takeover() -- block main thread to keep webplot server alive

Technical overview

The webplot embedded server is a waffle server running on a thread created by threads. The server starts with a task queue that you can use to give jobs to the server asynchronously. For example, you tell the server to setup a web page that prints a tensor.

local webplot = require 'webplot'

local data = torch.Tensor(3,3):fill(1)

webplot.dojob(
  function()
    app.get('/', function(req, res) -- app is an instance of waffle server
        res.send(tostring(data)) -- send the upvalue "data" when client "get \"
      end)
  end
)
-- do other stuff ...

webplot.takeover() -- block main thread

With dojob(), you can add any web page to the waffle server at any time without blocking your script!

Let's see how dygraph plot is implemented using dojob() and html rendering of waffle.

local webplot = require 'webplot'

local webplot_path = webplot.path
local webplot_host = webplot.host

local dygraph = {}

function dygraph.add(fig_path, data, options)
  webplot.dojob(
    function()
      _data[fig_path] = data
      _options[fig_path] = cjson.encode(options)
      app.get(fig_path, function(req, res)
          res.render(webplot_path .. 'dygraph.html', {
              data = cjson.encode(_data[fig_path]),
              options = _options[fig_path]
            })
        end)
    end)
end

Live update via Websocket

Live update is implemented using Websocket. See dygraph.lua and dygraph.html for example of establishing Websockt connection.