O₂graph script


Sometimes it’s helpful to be able to do some quick and dirty data analysis without having to write python directly. The O₂sclpy package includes a script called o2graph which is designed to enable quick analysis with text files or with HDF5 files (especially those generated by O₂scl). The O2graph script assumes that the O₂scl library has been installed separately (with HDF5 support enabled).

Basic usage

The o2graph script is formulated along the same lines as the acol executable in O₂scl documented at “The acol Command Line Utility”. It operates on one object at a time, and the basic workflow is the same: read or create an object, manipulate and/or plot that object, and save the object or the plot to a file.

Similar to acol, the o2graph list of commands and help screen changes depending on the type of the current object in memory. Commands common to all types are listed in o2graph --help or o2graph --commands. Commands applicable to objects of O₂scl type table are listed by o2graph --commands table. To obtain the help information on how a particular command works with a particular type, add the type and the command as arguments to help, e.g. o2graph --help table plot, which shows how to plot columns from table objects.

o2graph: A data viewing and processing program for O2scl.
  Version: 0.929
List of command-line options which do not require a current object:

  -addcbar         Add a color bar.
  -alias           Create a command alias.
  -arrow           Plot an arrow.
  -autocorr        Compute autocorrelation coefficients. 
  -backend         Select the matplotlib backend to use.
  -calc            Compute the value of a constant expression. 
  -canvas          Create a plotting canvas.
  -clear           Clear the current object. 
  -clf             Clear the current figure.
  -cmap            Create a continuous colormap or list colormaps.
  -colors          Show color information.
  -commands        List available commands for current or specified type.
  -constant        Get or modify a physical or numerical constant. 
  -convert         Manipulate or use a unit conversion factor. 
  -create          Create an object. 
  -docs            Open local HTML docs for O₂scl documentation. 
  -download        Download a file from the specified URL. 
  -ellipse         Plot an ellipse.
  -error-point     Plot a single point with errorbars.
  -eval            Run the python eval() function.
  -exec            Run the python code specified in a file.
  -exit            Exit (synonymous with 'quit').
  -filelist        List objects in a HDF5 file. 
  -generic         Read an object from a generic text file. 
  -get             Get the value of a parameter.
  -gltf            Produce a GLTF file with the current set of 3D objects.
  -h5-copy         Copy an O₂scl-generated HDF5 file. 
  -help            Show help information.
  -image           Plot a png file in a matplotlib window.
  -inset           Add a new set of axes
  -interactive     Toggle interactive mode. 
  -internal        Output current object in the internal HDF5 format. 
  -license         Show license information.
  -line            Plot a line from :math:`(x_1,y_1)` to :math:`(x_2,y_2)`
  -modax           Modify current axes properties.
  -mp4             Create an mp4 file from a series of images.
  -ninteg          Numerically integrate a user-specified function. 
  -no-intro        Do not print introductory text.
  -o2scl-addl-libs Specify a list of list of additional libraries to load.
  -o2scl-cpp-lib   Specify the location of the standard C++ library.
  -o2scl-lib-dir   Specify the directory for the libo2scl shared library.
  -output          Output the current object to screen or text file. 
  -plotv           Plot several vector-like data sets.
  -point           Plot a single point.
  -preview         Preview the current object. 
  -python          Begin an interactive python session.
  -quit            Quit (synonymous with 'exit').
  -read            Read an object from an O₂scl-style HDF5 file. 
  -rect            Plot a rectangle.
  -run             Run a file containing a list of commands.
  -save            Save the current plot in a file.
  -selax           Select an axis from the current list of axes
  -set             Set the value of a parameter.
  -shell           Run a shell command.
  -show            Show the current plot.
  -slack           Send a slack message. 
  -subadj          Adjust spacing of subplots
  -subplots        Create subplots.
  -td-arrow        Plot an arrow in a 3d visualization (experimental)
  -td-axis         Create a 3D axis (experimental).
  -td-axis-label   Create an axis label in a 3d visualization (experimental).
  -td-den-plot     Create a 3D density plot (experimental).
  -td-icos         Create a 3D icosphere (experimental).
  -td-mat          Create a 3d material (experimental)
  -td-pgram        Plot a parallelogram in a 3D visualization (experimental)
  -td-scatter      Create a 3D scatter plot (experimental).
  -text            Plot text in the data coordinates.
  -textbox         Plot a box with text.
  -ttext           Plot text in window coordinates [(0,0) to (1,1)].
  -type            Output the type of the current object. 
  -version         Print version information and O₂scl settings. 
  -warranty        Show warranty information.
  -wdocs           Open remote HTML docs for acol or an O₂scl topic. 
  -xlimits         Set the x-axis limits
  -xml-to-o2       Parse doxygen XML to generate runtime docs. 
  -xtitle          Add a title for the x-axis
  -ylimits         Set the y-axis limits
  -yt-ann          Annotate a yt rendering (experimental).
  -yt-arrow        Plot an arrow in a yt volume visualization. 
  -yt-axis         Add an axis to the yt volume.
  -yt-box          Create a box in a yt visualization. 
  -yt-line         Plot a line in a yt volume visualization.
  -yt-path         Add a path to the yt animation.
  -yt-render       Render the yt volume visualization.
  -yt-source-list  List yt sources
  -yt-text         Add text to the yt volume.
  -yt-tf           Edit the yt transfer function.
  -yt-xtitle       Add a title to the x axis in yt
  -yt-ytitle       Add a title to the y axis in yt
  -yt-ztitle       Add a title to the z axis in yt
  -ytitle          Add a title for the y-axis
  -zlimits         Set the z-axis limits

Additional help topics: functions, index-spec, markers, markers-plot,
mult-vector-spec, strings-spec, types, value-spec, and vector-spec.

Integration with O₂scl

The o2graph script implements all of the commands from the acol executable in O₂scl documented at “The acol Command Line Utility

First plot example

# This example creates a simple plot with one independent variable.
# The 'create' command creates an o2scl table object, 'function'
# creates a new column from a function, and 'deriv' creates a new
# column using interpolation to obtain the derivative. The command
# 'output' creates a HDF5 file which stores the full table. Quotes and
# parentheses are used to avoid confusion between negative values and
# commands. Also, in LaTeX strings, and extra space is placed after
# some $'s to avoid confusion with shell variables.
o2graph -backend Agg -create table x grid:-3.14,3.14,0.1 \
        -function "(1+sin(x))/2" y \
        -set xlo "(-3.14)" -set xhi 3.14 -xtitle "$ x$" -deriv x y yp \
        -preview 20 -internal data/ex1.o2 -plot x y marker=.,color=blue \
        -plot x yp lw=2,color=red -text 0.5 0.95 "$ f(x)$" \
        -text 1 0.05 "$ f^{\prime}(x)$" -save figures/table_plot.png

Density plot and contour line example

# This example creates a density plot and overlying contour plot
# with two independent variables.
o2graph -create table3d x grid:0,1,0.05 y "grid:(-1),0,0.05" \
        z "sin(x*6)*cos(y*6)" \
        -xtitle "$ \phi$" -ytitle "$ \eta$" \
        -den-plot z cmap=jet2 -contours 0.2 z \
        -plot lw=2,color=black -save figures/table3d_den_plot.png

Agg backend example

# This example uses the Agg backend to create plots stored as .png
# files without opening a plot window. The command '-clf' instructs
# o2graph to clear the current figure before starting a new plot
o2graph -backend Agg -create table x "grid:-3.14,3.14,0.1" \
        -function "(1+sin(x))/2" y -plot x y -save figures/backend_a.png \
        -clf -deriv x y yp -plot x yp -save figures/backend_b.png 

‘plotv’ example

# This example creates three tables with data and saves them to
# HDF5 files using the 'internal' command, then uses 'plotv' to
# plot the 'x' and 'y' columns from all three files together
o2graph -create table x "grid:(-3.14),3.14,0.1" \
        -function "sin(x)" y -internal data/table_plotv_a.o2 \
        -create table x "grid:(-3.14),3.14,0.1" \
        -function "cos(x)" y -internal data/table_plotv_b.o2 \
        -create table x "grid:(-3.14),3.14,0.1" \
        -function "cos(x+acos(-1))" y -internal data/table_plotv_c.o2 \
        -plotv hdf5:data/table_plotv_?.o2:acol:x \
        hdf5:data/table_plotv_?.o2:acol:y \
        -save figures/table_plotv.png

Scatter plot example

# This example demonstrates the use of 'scatter'. It creates a
# circular data set and uses the x value for the size of the points
# and the y value for the color. For no variation in either marker
# size or color, the string 'None' can be used in place of the name of
# the third or fourth column argument to the scatter command.
# For more detail, try e.g. 'o2graph -help table scatter'.
o2graph -create table N grid:0,10000,1 \
        -function "sin(1e8*N)" x -function "cos(1.001e8*N)*sqrt(1-x*x)" y \
        -function "4*abs(x)" s -function "abs(y)" c \
        -scatter x y s c -save figures/table_scatter.png

Region plot example

# This example demonstrates the use of 'rplot'. In this case
# the y-axis title is pushed a little too far to the left so
# we increase the left margin before plotting a little bit to compensate.
# For more detail, try e.g. 'o2graph -help table rplot'.
o2graph -create table x grid:0,1,1.0e-3 \
        -function "sin(4*x)" y1 \
        -function "sin(4*x)+0.3*cos(4*x)" y2 \
        -xtitle x -ytitle y -set fig_dict "left_margin=0.15" \
        -rplot x y1 x y2 -save figures/table_rplot.png

Error bars example

# An example with errorbars. A table is created to demonstrate
# plotting a dataset with error bars (the 'errorbar' command), and
# then three individual points are plotted with error bars (the
# 'error-point' command).
o2graph -create table x grid:0,1,8.0e-2 \
        -function "sin(4*x)" y \
        -function "0.06*(sqrt(x)+0.1)" xe \
        -function "0.07*(sqrt(abs(y))+0.1)" ye \
        -xtitle x -ytitle y \
        -errorbar x y xe ye \
        ecolor=red,elinewidth=2,capsize=3,capthick=3,lw=0 \
        -error-point 0.4 "(-0.25)" 0.1 0.2 ecolor=blue \
        -error-point 0.3 0.2 0.1 None 0.2 0.1 ecolor=green \
        -error-point 0.1 "(-0.5)" 0.1 0.2 0.3 0.4 \
        lolims=True,ecolor=black,capsize=4 \
        -save figures/table_errorbar.png

plot-color example

# An example of the 'plot-color' command. The third argument specifies
# the color value and the fourth argument specifies the color map.
# Note that 'plot-color' builds the curve up from line segments, so a
# relatively fine grid is needed to generate this image.
o2graph -backend Agg -create table x grid:0,1,0.002 -function "sin(100*x)" y \
-function "sqrt(x^2+y^2)" z -set fig_dict left_margin=0.15 \
-plot-color x y z jet -xtitle x -ytitle y \
-save figures/table_plot_color.png

Modifying axis example

# An example showing how to modify axes using the 'modax' command. 
o2graph -backend Agg -create table x grid:-3.14,3.14,0.1 \
        -function "(1+sin(x))/2" y \
        -set xlo "(-3.14)" -set xhi 3.14 -xtitle "$ x$" -deriv x y yp \
        -preview 20 -internal data/ex1.o2 -plot x y marker=.,color=blue \
        -plot x yp lw=2,color=red -text 0.5 0.95 "$ f(x)$" \
        -text 1 0.05 "$ f^{\prime}(x)$" \
        -modax x_loc=tb,y_minor_loc=0.1,y_tick_dir=inout,labelsize=20 \
        -modax y_tick_len=10,y_minor_tick_len=10 \
        -save figures/modax.png

Textbox example

# This example demonstrates the use of 'textbox'. 
o2graph -backend Agg \
        -set font 30 -textbox 0.5 0.9 test1 fc=#ffdddd color=red \
        -set usetex 0 \
        -textbox 0.5 0.7 test2 fc=#ddffdd,boxstyle=Circle,ec=blue,ls=: \
        fontfamily=serif,ha=left \
        -textbox 0.5 0.5 test3 \
        "fill=False,boxstyle=Sawtooth,ec=orange,ls=--,hatch=///" \
        "fontstyle=italic,rotation=10" \
        -ttext 0.5 0.3 "test4" \
        fontfamily=sans-serif,fontsize=28,backgroundcolor=#eeeeee \
        -rect 0.2 0.05 0.4 0.15 10 \
        fc=#bbeeee,ls=-.,lw=2,ec=black \
        -ellipse 0.7 0.1 0.2 0.1 "(-10)" \
        fc=#bbeeee,ls=-.,lw=2,ec=black \
        -save figures/textbox.png

Subplot example 1

# Subplot example with simple 'plot' functions. A two-by-two grid of
# subplots is created, sharing the x-axis between the first and
# second rows, and 'selax' is used to select the subplots.
o2graph -backend Agg -create table x func:1001:i/100.0 \
        -function "sin(x)" y1 \
        -function "cos(x)" y2 \
        -function "tan(x)" y3 \
        -function "atan(x)" y4 \
        -subplots 2 2 sharex=True \
        -selax 0 -set ylo "(-1)" -set yhi 1.0 -plot x y1 \
        -ytitle "y=sin(x)" \
        -selax 1 -set ylo "(-1)" -set yhi 1.0 -plot x y2 \
        -ytitle "y=cos(x)" \
        -selax 2 -set ylo "(-20)" -set yhi 19.9 -plot x y3 \
        -xtitle x -ytitle "y=tan(x)" \
        -selax 3 -set ylo "(0)" -set yhi 1.49 -plot x y4 \
        -xtitle x -ytitle "y=atan(x)" \
        -subadj hspace=0,left=0.14,right=0.98,top=0.98,bottom=0.11,wspace=0.41 \
        -save figures/subplots1.png

Subplot example 2

# Subplot example mixing 'plot' and 'den-plot' commands, with
# colorbars for the density plots. Setting colorbar to 1 implies that
# all future density plots will contain their own colorbar. The 'eval'
# command can be used to execute python code which isn't easily done
# with o2graph commands. One of the axes is not needed, so the 'eval'
# command is used to make it invisible.
o2graph -backend Agg -create table x func:1001:i/100.0 \
        -function "sin(x)" y1 \
        -function "cos(x)" y2 \
        -subplots 2 2 sharex=True \
        -selax 0 -set ylo "(-0.99)" -set yhi 1.0 -plot x y1 \
        -ytitle "y=sin(x)" \
        -selax 2 -set ylo "(-0.99)" -set yhi 1.0 -plot x y2 \
        -ytitle "y=cos(x)" -xtitle x \
        -create table3d x func:1001:i/100.0 y func:1000:i/100.0 \
        z "sin(x)*sin(y)" -function "sin(x)*cos(y)" z2 \
        -set colbar 1 \
        -selax 1 -den-plot z -modax x_visible=False \
        -xtitle x -ytitle "y=sin(x) sin(y)" \
        -selax 3 -set ylo 0 -set yhi 9 -den-plot z2 cmap=inferno \
        -xtitle x -ytitle "y=sin(x) cos(y)" \
        -subadj hspace=0,left=0.15,right=0.93,top=0.98,bottom=0.11,wspace=0.37 \
        -save figures/subplots2.png

Subplot example 3

# Subplots sharing a colorbar. In this example, the 'addcbar' command
# is used to create a independent color bar based on the last image
# plotted.
o2graph -backend Agg -create table x func:1001:i/100.0 \
        -function "sin(x)" y1 \
        -function "cos(x)" y2 \
        -subplots 2 2 sharex=True \
        -subadj hspace=0,left=0.15,right=0.84,top=0.98,bottom=0.12,wspace=0.55 \
        -selax 0 -set ylo "(-0.99)" -set yhi 1.0 -plot x y1 \
        -ytitle "y=sin(x)" \
        -selax 1 -set ylo "(-0.99)" -set yhi 1.0 -plot x y2 \
        -ytitle "y=cos(x)" \
        -create table3d x func:1001:i/100.0 y func:1001:i/100.0 \
        z "sin(x)*sin(y)" -function "sin(x)*cos(y)" z2 \
        -selax 2 -den-plot z \
        -xtitle x -ytitle "y=sin(x) sin(y)" \
        -selax 3 -den-plot z2 \
        -xtitle x -ytitle "y=sin(x) cos(y)" \
        -addcbar 0.85 0.12 0.04 0.86 \
        -selax \
        -save figures/subplots3.png

Colormap and transparency example

o2graph -create table3d x grid:0,1,0.01 y grid:0,1,0.01 z x \
-set xlo "(-0.01)" -set xhi 1.01 -set ylo "(-0.04)" -set yhi 4.04 \
-set font 30 \
-ttext 0.5 0.125 "transparency demo blue00" zorder=2 \
-line 0.1 0.5 0.9 0.5 "color=black,zorder=1" \
-cmap blue00 "[1,1,1,0]" "[0,0,1,0]" \
-den-plot z "cmap=blue00,zorder=3" \
-ttext 0.5 0.375 "transparency demo blue01" zorder=2 \
-line 0.1 1.5 0.9 1.5 "color=black,zorder=1" \
-set-grid 1 y+1 \
-cmap blue01 "[1,1,1,0]" "[0,0,1,1]" \
-den-plot z "cmap=blue01,zorder=3" \
-ttext 0.5 0.625 "transparency demo blue10" zorder=2 \
-line 0.1 2.5 0.9 2.5 "color=black,zorder=1" \
-set-grid 1 y+1 \
-cmap blue10 "[1,1,1,1]" "[0,0,1,0]" \
-den-plot z "cmap=blue10,zorder=3" \
-ttext 0.5 0.875 "transparency demo blue11" zorder=2 \
-line 0.1 3.5 0.9 3.5 "color=black,zorder=1" \
-set-grid 1 y+1 \
-cmap blue11 "[1,1,1,1]" "[0,0,1,1]" \
-den-plot z "cmap=blue11,zorder=3" -save figures/cmap_den_plot.png

KDE plot example

o2graph -backend Agg -set fig_dict fig_size_x=8,fig_size_y=4 \
        -create table x grid:-3.14,3.14,0.1 \
        -function "(1+sin(x))/2" y \
        -function "(1+cos(x))^(0.8)/2" z \
        -subplots 1 2 -selax 0 -kde-plot \
        y x_min=-0.5,x_max=1.5,y_mult=15,lw=2 \
        -hist-plot y bins=20 -selax 1 \
        -kde-2d-plot y z cmap=Purples -subadj \
        left=0.07,right=0.89,top=0.97,bottom=0.11,wspace=0.18 \
        -addcbar 0.90 0.11 0.035 0.86 \
        -save figures/kde_plot.png

Internal structure

The O2graph script works by creating an instance of the o2sclpy.o2graph_plotter class and calling the function o2sclpy.o2graph_plotter.parse_argv() . Internally, the o2graph_plotter class works by calling the global functions mentioned in the Python Integration page in the in the O2scl documentation.