Example 1: Plotting the built-in function 'log' ;;; Plot the function log(x) from x = 1 to x = 10 in steps of 1/10 ;;; create an empty picture rc_start(); ;;; variable to hold the output of rc_graphplot. vars region; rc_graphplot( 1, 1/10, 10, 'X', log, 'log(X)') -> region; This is what is displayed:
;;; The resulting list, region, shows the rounded bounds of the
;;; rectangle containing the resulting graph:
region =>
** [1 10 0 3]
;;; I.e., as x moved between 1 and 10, y remained between. 0 and 3
Example 2: Plotting the user-defined function 'myfunc' define myfunc(x) -> y; ;;; A function to be plotted - actually a polynomial lvars x y; 2 * x**4 + x**3 - 16 * x**2 + 50 -> y enddefine; ;;; Plot the function myfunc(x) from x = -3 to x = 3 in steps of 1/10 rc_graphplot( -3, 1/10, 3, 'X', myfunc, 'Y') -> region; region ==> ** [-3 3 0 110] ;;; Here the maximum value of y is 110
region ==>
** [-3 3 0 110]
;;; Here the maximum value of y is 110
Example 3: Plotting specific data-points Suppose you have done an experiment and recorded some data you would like to plot, and that you have stored them in a Pop-11 data structure such as a list, a vector, an array, or a string. To simulate this, load these two lines of code: vars mydata; [13 12 7 3 1 1 19 29 25 20 undef 15 10 3 -3 2 1] -> mydata; The "undef" value means that something went wrong and there is no value for this time. Let's say the data were collected at 5-second intervals, starting at 20 seconds into the experiment. This would then be an appropriate call to the routine: rc_graphplot( 20, 5, 100, 'time (s)', mydata, 'Data') -> region; Which produces:
region =>
** [20 100 -10 35]
Example 4: Plotting x and y together - separate data sets or functions If you have two sets of data, and you want to plot one set against the other, you simply pass these to graphplot with the x data first, each set followed by its label. The data can be lists, vectors, arrays, or any other subscriptable structure. In this example, the two vectors might represent the x and y coordinates of moving object, for example. vars xvals, yvals, region; { 2 3 2 3 5 7 8 7 8 6 4} -> xvals; {20 24 28 30 31 28 33 26 19 23 24} -> yvals; rc_graphplot(xvals, 'X', yvals, 'Y') -> region;
region =>
** [1 9 16 36]
This would do the same:
vars xyvals;
[{2 20} {3 24} {2 28} {3 30} {5 31} {7 28} {8 33} {7 26} {8 19}
{6 23} {4 24}] -> xyvals;
;;; Use RC_GRAPHPLOT2
uses rc_graphplot2
rc_graphplot2(xyvals, 'X', 'Y') -> region;
Example 5: Plotting x and y together - combined data set or function Sometimes, it may be more convenient to store x-y data as a single data structure containing pairs of values, or to plot the results of a single function which returns x and y values together. To do this, you will need to load a different version of graphplot - LIB * GRAPHPLOT2, thus: ;;; Define a function that produces two values each time it is ;;; called. define xy_func(t) -> (x,y); lvars t x y; t * cos(t) -> x; t * sin(t) -> y enddefine; ;;; Plot this for values of t from 0, increasing by 2, to 3200: rc_graphplot2(0, 2, 3200, xy_func, 'X', 'Y') -> region;
See the automatically computed bounds:
region =>
** [-4000 4000 -4000 4000]
Example 6 Plotting points instead of lines You might prefer to plot points on the graph instead of drawing lines between the data points or function values. This can be done by changing the value of one of the many controlling global variables, like this: ;;; Use RC_GRAPHPLOT2 uses rc_graphplot2 ;;; data to be plotted vars xyvals; [{2 20} {3 24} {2 28} {3 30} {5 31} {7 28} {8 33} {7 26} {8 19} {6 23} {4 24}] -> xyvals; ;;; specify shape to be drawn at each point "plus" -> rcg_pt_type; ;;; specify diameter of shape 20 -> rcg_pt_cs; rc_graphplot2( xyvals, 'X', 'Y') -> region;
The region
region =>
** [1 9 16 36]
You will find that the individual points are plotted with "plus" signs.
Other words that you can assign to rcg_pt_type are "square", "cross",
"plus" and "circle". More might be added in due course. You can assign a
plotting procedure of your own to rcg_pt_type - it must take two
arguments, x and y.
Example 7: Repeat but drawing circles instead of crosses "circle" -> rcg_pt_type; 30 -> rcg_pt_cs; rc_graphplot2( xyvals, 'X', 'Y') -> region; That produces
To get back to drawing lines, do this:
"line" -> rcg_pt_type;
Example 8: Drawing several graphs on the same axes So far, the program has started setting the scales from scratch for each graph, and has cleared the window between graphs. Often, however, you will want to put several curves or sets of data on the same axes. Let's plot some data, and a curve (the square root function) that happens to fit them approximately, on the same axes. We start by setting up some more synthetic data and plotting them, using crosses of diameter 20: rc_start(); vars moredata; [0.1 0.9 1.3 1.8 1.95 2.2 2.5 2.9 3.1 3.2 3.4 3.45 3.5] -> moredata; "cross" -> rcg_pt_type; 20 -> rcg_pt_cs; rc_graphplot(0, 1, 12, 'X', moredata, 'Y') -> region; We'll now change the plotting style so that the theoretical function comes out as a line: "line" -> rcg_pt_type; ;;; make it look different Now we change some more global variables and plot the curve for sqrt. false -> rcg_newgraph; ;;; don't clear the window region -> rcg_usr_reg; ;;; use same axes as before undef -> rcg_win_reg; ;;; use same bit of window as before rc_graphplot(0, 1/10, 12, false, sqrt, false) -> region;
More examples can be found in TEACH RC_GRAPHPLOT