[Maxima-bugs] [ maxima-Bugs-3100138 ] Inconsistent evaluation in plot2d

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Bugs item #3100138, was opened at 2010-10-31 19:52
Message generated for change (Settings changed) made by crategus
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Category: Lisp Core - Plotting
Group: None
>Status: Closed
>Resolution: Works For Me
Priority: 5
Private: No
Submitted By: MSP1 (msp1)
Assigned to: Nobody/Anonymous (nobody)
Summary: Inconsistent evaluation in plot2d

Initial Comment:
I was trying to produce "staircase" plots of computed and experimental data held in a list when I found the problem illustrated in simplified form by the following lines.

(%i1) askinteger(round(x));                 /* No problem here */
(%o1)                                 yes
(%i2) define_variable(data, [1.2, 4.6, 7.2, 5.6, 2.3], float);
(%o2)                      [1.2, 4.6, 7.2, 5.6, 2.3]
(%i3) data[round(2.6)];                     /* Nor here */
(%o3)                                 7.2
(%i4) plot2d(data[round(i)], [i, 1, 5]);   /* but oops! */
apply: subscript must be an integer; found: round(i)  

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>Comment By: Dieter Kaiser (crategus)
Date: 2010-10-31 20:47

Message:
The documentation of plot3d has an example which shows the way to get a
plot for an integer function. The trick is to use the quote operator when
passing the function as an argument to the plot command:

plot2d('data[round(i)], [i, 1, 5]);

Closing this bug report as "works for me".
Dieter Kaiser

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You can respond by visiting: 
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