Class: BPlot

Inherits:
Object
  • Object
show all
Defined in:
lib/bplot.rb

Overview

BPlot is a 2D and 3D plotting module for SciRuby. It provides a simple API that will be familiar to Gnuplot users and to a lesser extent Matlab users. BPlot is in ALPHA status. Two dimmensional plots seem to work well but they really need more testing. Also, the API is not yet settled and may change without warning. Many features are not yet implemented, including surface plots.

Instance Method Summary collapse

Constructor Details

#initialize ⇒ BPlot

Create new engine

Every call to BPlot#new creates a new instance of Gnuplot. You can have multiple instances of Gnuplot in the same Ruby script.

Example

b.BPlot.new
b.cmd('plot sin(x)')



52
53
54
55
56
57
58
59
60
61
62
63
64
 
# File 'lib/bplot.rb', line 52

def initialize()
  #
  # Every instance of BPlot has its own gnuplot process.
  #
  @pipe = IO.popen("gnuplot -p","w")
  
  #
  # Configure Gnuplot.
  #
  @pipe.puts "set terminal wxt"      # Nice GUI for plots.
  @pipe.puts "set termoption dashed"   # Needed for 'r--', 'r.-', 'r:'
  @pipe.puts "set termoption enhanced" # Support superscripts + subscripts.
end

Instance Method Details

#cmd(str) ⇒ Object

Issue raw command

Send a raw command to the Gnuplot backend. This gives the user more control over plotting engine.

Example

b.BPlot.new
b.cmd('plot sin(x)')



77
78
79
 
# File 'lib/bplot.rb', line 77

def cmd(str)
  @pipe.puts str
end

#multiplot(opts = '') ⇒ Object

Multiplot

In multiplot mode, multiple plot commands are placed togeher in the same window. This can be a convenient alternative to having a very long multiple-line plot command. It allso allows you to add plots using loops and other constructions.

Examples

b.multiplot do
  plot(x, y1)
  plot(x, y2)
  plot(x, y3)
end

b.multiplot do
  (0..10).each { |t| plot( x, sin(x + v*t) ) }
end



163
164
165
166
167
 
# File 'lib/bplot.rb', line 163

def multiplot(opts='')
  @pipe.puts "set multiplot #{opts}"
  yield if block_given?
  @pipe.puts "unset multiplot"
end

#plot(*args) ⇒ Object

2D Plotting

This is the key method in BPlot, as it is responsible for all 2D plots. This method is currently in a state of flux and is for the moment undocumented.



173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
 
# File 'lib/bplot.rb', line 173

def plot(*args)
  
  all_data = []
  all_plots = ''
  while args.length > 0
    #
    # NEXT PLOT
    #
    # Anything that is of class Array or NMatrix is data.
    this_data = []
    while args[0].class == 'Array' or args[0].class == 'NMatrix'
      this_data << args.shift
    end
    
    all_data << this_data
    
    # - Get the settings for this plot.
    # - If 'args' is not empty, there is another plot.
    this_plot, args = styles(args)
    all_plots << this_plot
    all_plots << ', ' if args.length > 0
  end
  
  # TODO:
  #   -   Check for both Array and NMatrix.
  #   -   But make sure the program works without NMatrix loaded.
  #
  
  #
  # Each plot needs a separate stream of data separated by 'e' ("end").
  #
  nblocks = all_data.length
  
  stream = (1..nblocks).map { |s|
    
    ncols = all_data[s].length
    nrows = all_data[s][0].class == 'Array' ? all_data[s][0].length
                                            : all_data[s][0].shape[0] - 1
    
    (0..nrows).map { |r|
    (0..ncols).map { |c|  "     " + all_data[s][c][r]
    }.join + "\n"
    }.join + "e\n"
  }.join
  
#   stream = (1..nstreams).map { |s|
#     x = data.shift
#     y = data.shift
#     n = x.is_a?(Array) ? x.length - 1 : x.shape[0] - 1
#     
#     (0..n).map { |i| "#{x[i]} #{y[i]}\n" }.join + "e\n"
#   }.join
  
  @pipe.puts "plot #{all_plots} \n#{stream}"
end

#refresh ⇒ Object

Refresh

This command reformats and redraws the current plot with the latest settings. This is useful for viewing a plot with different “set” options, or for generating the same plot for several output formats.

Example

b.set('terminal postscript')
b.set('output "myplot.ps"')
b.refresh

b.set('terminal png')
b.set('output "myplot.png"')
b.refresh



141
142
143
 
# File 'lib/bplot.rb', line 141

def refresh()
  @pipe.puts "refresh"
end

#set(str) ⇒ Object

Settings

This method is a thin wrapper around the Gnuplot “set” command. It can be used to set *a lot* of options. However, nothing is drawn until the user issues a plotting command. See the examples below for a quick overview. See the Gnuplot documentation for more details.

Examples

b.set('terminal enhanced postscript color')
b.set('output "myplot.ps"')
b.set('xrange [0:10]')
b.set('yrange [0:50]')
b.set('xlabel "This is the X Axis"')
b.set('ylabel "This is the Y Axis"')
b.set('title "A title for the whole plot"')



100
101
102
 
# File 'lib/bplot.rb', line 100

def set(str)
  @pipe.puts "set #{str}"
end

#show(str) ⇒ Object

Show

The set command can be used to set lots of options. No screen is drawn, however, until a plotting command is given. The show command shows their settings; show(‘all’) shows all the settings.



120
121
122
 
# File 'lib/bplot.rb', line 120

def show(str)
  @pipe.puts "show #{str}"
end

#unset(str) ⇒ Object

Settings

This method is a thin wrapper around the Gnuplot “unset” command. It is used to reset settings back to their default values. See the documentation on “set” for more information. See also the Gnuplot documentaion for “set” and “unset”.



110
111
112
 
# File 'lib/bplot.rb', line 110

def unset(str)
  @pipe.puts "unset #{str}"
end