PyGnuplot: Python wrapper for Gnuplot

Author: Ben Schneider

Requires:

Gnuplot ()

Installation:

Using pip

pip install PyGnuplot

Using conda

conda install -c benschneider pygnuplot

Upgrade:

pip install --upgrade  PyGnuplot

Basic Usage:

from PyGnuplot import gp
figure1 = gp()  # Create a new figure handle
figure2 = gp(r"C:\Program Files\gnuplot\bin\gnuplot.exe")  # Can also specify which gnuplot to use
figure1.a("plot sin(x)")
figure2.a("plot cos(x)")
pi = figure.a("print pi")

Functions available with each figure:

c(command)

pipe a command to gnuplot as if in gnuplot command promt

c('plot sin(x)')

save(data, filename='tmp.dat')

save arrays into file (filename = 'tmp.dat') easily read by Gnuplot

s([X,Y,Z])  # creates tmp.dat

c('plot "tmp.dat" u 1:2')

a(command='', vtype=str, timeout=0.05)

> asks gnuplot: it sends a command to gnuplot and returns its response > This is paricularly handy when using gnuplots fitting features vtype > can be used to change the return format timeout is the time to wait > for a response

a('print pi')  # returns the value of pi

a('print pi; print pi')  # returns 2 times the value of pi

r(vtype=str, timeout=0.05)

> reads the gnuplot return buffer until its empty

plot(data, filename='tmp.dat')

> Plot some data. Sends plot instructions and the data to Gnuplot

plot([x,y])

plot_b(data, v1='d', v2='%double')

> Similar to plot: Sends plot instructions and the data to Gnuplot > However it sends them in binary format, which can be beneficial when > the dealing with larger quanities of numbers

p(filename='tmp.ps', width=14, height=9, fontsize=12, term='x11')

Create postscript file (overwrites existing)

p('myfile.ps')

pdf(filename='tmp.pdf', width=14, height=9, fontsize=12, term='x11')

Create a pdf file (overwrites existing)

pdf('myfile.pdf')

quit()

> Closes windows,then gnuplot, then the pipe

Setup terminal

> This script will use the same default terminal that gnuplot used (it > reads the GPVAL_TERM value when gnuplot starts up) it can still be > modified by the 'default_term' variable:

from PyGnuplot import gp
fig1 = gp()
fig1.default_term = 'wxt'

New features:

fit2d(data, func='y(x)=a + b*x', via='a,b', limit=1e-9)

> Quickly Fit a simple 2-D data set and return the fitting results. This > uses the new ask function "a()" Here we gather the fitting info from > gnuplot

and:

fit(self, data, func='y(x)=a + b*x', via='a,b', limit=1e-9, filename='tmp.dat', wait=1)

> Allows for sligtly more complex fitting, filename: stores data first > into a temporary file default: tmp.dat wait: define a waiting time in > sec for gnuplot to finish its fitting default: 1sec

import numpy as np
f1 = gp()
x = np.linspace(0, 20, 1001)
yn = np.random.randn(1001)/10
y = np.sin(x)
data = [x, y+yn]
func = 'y(x) = a + b*cos(x + c)'  # define a fitting function here.
(a, b, c), report = f1.fit2d(data, func, via='a,b,c', limit=1e-9) # sending in the data the function used to fit and the variables that are to be found.
f1.save(data, "tmp.dat")
f1.a('plot "tmp.dat" w lp')
f1.a('replot y(x)')

Examples:

• 1 Example code

from PyGnuplot import gp
import numpy as np
X = np.arange(10)
Y = np.sin(X/(2*np.pi))
Z = Y**2.0
fig1 = gp()
fig1.save([X,Y,Z])
fig1.c('plot "tmp.dat" u 1:2 w lp)
fig1.c('replot "tmp.dat" u 1:3' w lp)
fig1.p('myfigure.ps')

• 2 Example file

python example.py