A simple module for generating plots from Fortran using Python's matplotlib.pyplot.

Status

Overview

Currently, this module can be used to generate simple plots from Fortran. Eventually, it may be expanded to provide additional features and other types of plots.

The way it works is simply to generate a Python script with the plotting code, which is then executed from the command line using the Fortran execute_command_line function.

Compiling

The module requires a modern Fortran compiler (it uses various Fortran 2003/2008 features such as deferred-length strings). It should work fine with the latest gfortran or ifort compilers.

A fpm.toml file is provided for compiling pyplot-fortran with the Fortran Package Manager. For example, to build:

fpm build --profile release

By default, the library is built with double precision (real64) real values. Explicitly specifying the real kind can be done using the following processor flags:

Preprocessor flag	Kind	Number of bytes
REAL32	real(kind=real32)	4
REAL64	real(kind=real64)	8
REAL128	real(kind=real128)	16

For example, to build a single precision version of the library, use:

fpm build --profile release --flag "-DREAL32"

To run the unit tests:

fpm test

To use pyplot-fortran within your fpm project, add the following to your fpm.toml file:

[dependencies]
pyplot-fortran = { git="https://github.com/jacobwilliams/pyplot-fortran.git" }

or, to use a specific version:

[dependencies]
pyplot-fortran = { git="https://github.com/jacobwilliams/pyplot-fortran.git", tag = "3.3.0" }

To generate the documentation using ford, run: ford ford.md

Supported plot types

• matplotlib.pyplot.plot -- 2D/3D plot of lines and/or markers
• matplotlib.pyplot.bar -- bar plot
• matplotlib.pyplot.contour -- contour plot
• matplotlib.pyplot.contourf -- filled contour plot
• matplotlib.pyplot.imshow -- image plot
• matplotlib.pyplot.hist -- histogram plot
• matplotlib.pyplot.errorbar -- errorbar plot
• mpl_toolkits.mplot3d.axes3d.Axes3D.plot_surface -- surface plot
• mpl_toolkits.mplot3d.axes3d.Axes3D.plot_wireframe -- 3D wireframe

Example

The following example generates a plot of the sine function:

 program test

 use,intrinsic :: iso_fortran_env, only: wp => real64
 use pyplot_module

 implicit none

 real(wp),dimension(100) :: x,sx
 type(pyplot) :: plt
 integer :: i

 !generate some data:
 x = [(real(i,wp), i=0,size(x)-1)]/5.0_wp
 sx = sin(x)

 !plot it:
 call plt%initialize(grid=.true.,xlabel='angle (rad)',&
                     title='Plot of $\sin(x)$',legend=.true.)
 call plt%add_plot(x,sx,label='$\sin(x)$',linestyle='b-o',markersize=5,linewidth=2)
 call plt%savefig('sinx.png', pyfile='sinx.py')

 end program test

Documentation

• The API documentation for the current master branch can be found here. This is generated by processing the source files with FORD.

See also

• Matplotlib