## Forum archive 2000-2006

### Lars Jensen - Format number of sample points on graph?

by Arnold Pizer -
Number of replies: 0
 Format number of sample points on graph? topic started 8/1/2004; 5:25:14 PMlast post 8/6/2004; 5:37:13 PM
 Lars Jensen - Format number of sample points on graph?  8/1/2004; 5:25:14 PM (reads: 1138, responses: 4) When producing a graph for a problem, how do I increase the number of sample points on the graph, so the plot looks less jagged? Thanks, Lars. <| Post or View Comments |>

 Michael Gage - Re: Format number of sample points on graph?  8/2/2004; 1:05:18 PM (reads: 1335, responses: 0) Hi Lars, which describes the commands in Fun.pm Once you have created a Function object $fn, you can change the number of steps used in graphing the function using$fn->steps(50); you can determine the current or default value with $current_steps =$fn->steps(); You can also reset the domain of the function. -- Mike <| Post or View Comments |>

 Lars Jensen - Re: Format number of sample points on graph?  8/3/2004; 6:42:37 PM (reads: 1361, responses: 0) Hi Mike, Thanks for your response. Your method is not immediately clear to me - I was using the method described in Shemanske's "Newbie Guide" to include the graph... Are there any good sample problem in one of the libraries that uses above method? Thanks, Lars. <| Post or View Comments |>

 Michael Gage - Re: Format number of sample points on graph?  8/4/2004; 3:05:57 PM (reads: 1322, responses: 0) Perhaps this will help. (It's from PGgraphmacros.pl description. Slightly cleaned up from that description)  $f1 = FEQ( qq! x^2 - 3*x + 45 for x in [0, 45) using color:red and weight:2!); Usage: ($fn1, $fn2,$fn3) = plot_functions($graph,$f1, $f2,$f3); Synonym: add_functions($graph,$f1,$f2,$f3); (This isn't has clear as it should be in the original description since the outputs there were also labeled $f1,$f2 and $f3. The$f1 output (now called $fn1) is a function object, while the$f1 input is just a string. plot_functions was designed as a front end macro which simplies constructing function objects. The output of plot_functions is a Fun with the methods described in Fun.pm. To change the number of points in plotting the function you need the following statement, after the plot_functions statement, but before the "insertGraph" statement. \$fn1->steps(100); This will set the number of steps used in plotting the function to 100. You might also try setting it first to 4 steps so that you can clearly see the effect of changing the number of steps. Note that despite its name, plot_functions doesn't actually draw the graph when it is executed, it translates the string into a function object capable of drawing the graph, and returns a reference to the function object. (It also inserts this function object into the graph.) The graph is not actually crteated/drawn until the insertGraph command is executed, so changes made in the function objects before that command will affect the graph. Hope this helps. -- Mike <| Post or View Comments |>

 Lars Jensen - Re: Format number of sample points on graph?  8/6/2004; 5:37:13 PM (reads: 1340, responses: 0) Hi Mike, Thanks a lot. This really helped. Lars. <| Post or View Comments |>