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Last modified: 11 October 2018

URL: https://cxc.cfa.harvard.edu/chips/convert/compare.html

Conversion to Python

Here we convert several CIAO 3 plots to the Python interface of CIAO 4. The examples use a text file, sample.txt, whose contents are 

# x y dy
1   10    3
2.5 20    5
5   17    5
9   21  5.5
12  -5    3
20  25    7
40  80   11

A complete list of all the CIAO 3.4 ChIPS commands and their Python equivalents in CIAO 4 is also available.

A simple plot

This example illustrates how you convert several common CIAO 3.4 commands, including CURVE, LABEL, LINE, XLABEL, YLABEL, TITLE, and PRINT.

CIAO 3.4 output CIAO 4 output
[Plot 1, CIAO 3.4] [Plot 1, CIAO 4]

CIAO 3 command language

unix% chips

Welcome to ChIPS, version CIAO 3.4
Copyright (C) 1999-2003, Smithsonian Astrophysical Observatory

chips> curve "sample.txt" x 1 y 2
chips> sym square
chips> label 5 70 "Main sample (\beta<0.5)"
chips> line -100 -100 100 100
chips> line red
chips> line dash
chips> xlabel "r (kpc)"
chips> ylabel "\alpha / \alpha_0"
chips> title "Comparison plot 1"
chips> label size 1.2
chips> xlabel size 1.2
chips> ylabel size 1.2
chips> title size 1.2
chips> print postfile plot1.ps
chips> info

Drawing Area  #1  << CURRENT DRAWING AREA
(Location: 0.15 0.9 0.1 0.9) 
(Limits  : -0.95 41.95 -9.25 84.25) 
(Axes    :  fouraxes   color: defaultcolor  width: 1) 
        Curve #1  /data/chips/sample.txt
                 SYMBOL: defaultcolor  square 
                 CONNECTOR: noline  << CURRENT CURVE
        Label #1  "Main sample (\beta<0.5)" Location: (5, 70) Size: 1.2  << CURRENT LABEL
        Line  #1  Starting at (-100, -100) ending at (100, 100) Color: red   << CURRENT LINE

where bold text in the output from INFO is used to indicate text in reverse video.

CIAO 4 version

unix% chips 
-----------------------------------------
Welcome to ChIPS: CXC's Plotting Package
-----------------------------------------
CIAO 4.7 ChIPS version 1 Thursday, December 4, 2014

chips-1> add_curve("sample.txt[cols x,y]", ["line.style", "none"])
chips-2> set_curve(["symbol.style", "square", "symbol.fill", False])
chips-3> add_label(5, 70, r"Main sample (\beta<0.5)")
chips-4> add_line (0, 0, 40, 40, ["extend", "both", "color", "red", "style", "longdash"])
chips-5> set_plot_xlabel("r (kpc)")
chips-6> set_plot_ylabel(r"\alpha / \alpha_0")
chips-7> set_plot_title("Comparison plot 1")
chips-8> set_label(["size", 18])
chips-9> set_axis(["label.size", 18])
chips-10> set_plot(["title.size", 18])
chips-11> print_window("plot1") 
chips-12> info()

Window [win1]
  Frame [frm1]
    Plot [plot1]   (0.15,0.15)  .. (0.90,0.90)
      Border bottom [bx1]  top [bx2]  left [by1]  right [by2]
      Curve [crv1]
      X Axis [ax1]
      Y Axis [ay1]
      Label [lbl1]
      Line [line1]

chips-13> get_plot_xrange()
          [-0.9500000000000002, 41.95]
chips-14> get_plot_yrange()
          [-9.25, 84.25]
chips-15> get_line()

color = red
depth = 100
extend = 3
id = None
stem = None
style = 5
thickness = 1.0

Two plots: plotting data from a file and from arrays

This example show how you convert the SPLIT and RELSIZE commands, as well as the curve() S-Lang function.

CIAO 3.4 output CIAO 4 output
[Plot 2, CIAO 3.4] [Plot 2, CIAO 4]

Note that the blue dotted line connecting the curve is not drawn to the point that has y < 0 in CIAO 4, due to the logarithmic scale used for the Y axis, whereas it was in CIAO 3.4 (or at least a line was drawn vertically down).

CIAO 3 command language

unix% chips

Welcome to ChIPS, version CIAO 3.4
Copyright (C) 1999-2003, Smithsonian Astrophysical Observatory

chips> curve "sample.txt" x 1 y 2 e 3
chips> log y
chips> limits y 6 auto
chips> sym magenta
chips> err red
chips> simpleline
chips> blue
chips> longdash
chips> split 2
chips> split gap 0.1
chips> relsize 2
chips> d 2
chips> x = [1:10:0.1];
chips> y = sin(x);
chips> () = curve(x,y);
chips> simpleline
chips> sym none
chips> magenta
chips> xlabel x_2
chips> ylabel y_2
chips> xlabel size 1.6
chips> ylabel size 1.6
chips> xlabel magenta
chips> ylabel magenta
chips> d 1
chips> xlabel \eta
chips> ylabel "rate (count s^{-1})"
chips> xlabel size 1.6
chips> ylabel size 1.6
chips> print postfile plot2.ps

CIAO 4 version

unix% chips
-----------------------------------------
Welcome to ChIPS: CXC's Plotting Package
-----------------------------------------
CIAO 4.7 ChIPS version 1 Thursday, December 4, 2014

chips-1> add_curve("sample.txt[cols x,y,dy]", ["line.style", "none"])
chips-2> log_scale(Y_AXIS)
chips-3> ci = ChipsCurve()
chips-4> ci.err.style = "cap"
chips-5> ci.err.color = "red"
chips-6> ci.line.style = "longdash"
chips-7> ci.line.color = "blue"
chips-8> ci.symbol.color = "magenta"
chips-9> set_curve(ci)
chips-10> split(2, 1, 0.1)
chips-11> adjust_grid_yrelsize (1,  2)
chips-12> x = np.arange(1, 10, 0.1)
chips-13> y = np.sin(x)
chips-14> add_curve(x, y, ["line.color", "magenta", "symbol.style", "none"])
chips-15> set_plot_xlabel("x_2")
chips-16> set_plot_ylabel("y_2")
chips-17> set_axis(["label.size", 18, "label.color", "magenta"])
chips-18> current_plot("plot1")
chips-19> set_plot_xlabel(r"\eta");      
chips-20> set_plot_ylabel("rate (count s^{-1})")
chips-21> set_axis(["label.size", 18])
chips-22> set_xaxis(["offset.perpendicular", 35])
chips-23> print_window("plot2")

Preferences and Histograms

This example show how you set preferences and draw histograms (i.e. how to convert the STEP command).

CIAO 3.4 output CIAO 4 output
[Plot 3, CIAO 3.4] [Plot 3, CIAO 4]

The four major differences in these plots are:

  1. The histogram can be filled (in this case a solid green, but changing the opacity and fill patterns are also possible).
  2. The histogram edges are now drawn down to y=0.
  3. The auto scaling now considers the edges of the bins rather than the bin centers (which is why the X axis now goes up to 50).
  4. The symbol is now drawn on top of the line, not the other way around.

CIAO 3 command language

unix% chips

Welcome to ChIPS, version CIAO 3.4
Copyright (C) 1999-2003, Smithsonian Astrophysical Observatory

chips> chips.symbolstyle = _chips->soliddiamond
chips> chips.symbolcolor = _chips->blue
chips> chips.curvecolor = _chips->red
chips> chips.curvestyle = _chips->step
chips> curve sample.txt x 1 y 2
chips> longdash

CIAO 4 version

unix% chips
-----------------------------------------
Welcome to ChIPS: CXC's Plotting Package
-----------------------------------------
CIAO 4.7 ChIPS version 1 Thursday, December 4, 2014

chips-1> pr = ChipsHistogram()
chips-2> pr.symbol.style = "diamond"
chips-3> pr.symbol.fill = True
chips-4> pr.symbol.color = "blue"
chips-5> pr.line.color = "red"   
chips-6> set_preferences(pr)  
chips-7> add_histogram("sample.txt[cols x,y]")
chips-8> set_histogram(["line.style", "longdash", "fill.visible", "solid", "fill.color", "green"])

If you only wanted to override the preferences for the add_histogram call - so that future calls use the original preference settings - then you would say 

add_histogram("sample.txt[cols x,y]", pr)

instead of lines 6 and 7 above.