RE: Part 2 of a recent post on Plot and v 5

*To*: mathgroup at smc.vnet.net*Subject*: [mg44406] RE: [mg44358] Part 2 of a recent post on Plot and v 5*From*: "David Park" <djmp at earthlink.net>*Date*: Sat, 8 Nov 2003 04:50:49 -0500 (EST)*Sender*: owner-wri-mathgroup at wolfram.com

Mariusz, Selecting the "interesting" portion of a plot is not a new feature in Mathematica. I don't think the algorithm is public and it has apparently changed between Version 4 and 5. Even if you had the algorithm it probably wouldn't help much in predicting the plot outcome in advance. Would you prefer that PlotRange -> All be the default, instead of PlotRange -> Automatic? Then what would you think of the following plot? Plot[Tan[x], {x, -10, 10}, PlotRange -> All] It might seem that it would be more reasonable to have Mathematica adjust the y range and leave the x range untouched. But what about other plot types such as ParametricPlot or ImplicitPlot? Mathematica cannot always tell which axes you consider to be more fundamental. The Mathematica plot types make great plots for many common cases with very minimum coding. But this is deceptive. In many other cases one is just going to have to add options and perhaps more complicated coding to get a desirable plot. There is no way that a simple Plot command is going to be able to make the correct choices for every case thrown its way. In any case, the "correct" choice may very much depend upon the user's personal preferences. Good graphics is an art and in most cases you are going to have to work with it a little. Whatever graphics program you use will have some conventions that you will have to live with. There is a perfectly simple method to make your plot come out the way you want. If your position is that you don't ever want to add an option, then I think that is both unrealistic and unwise. David Park djmp at earthlink.net http://home.earthlink.net/~djmp/ From: Mariusz Jankowski [mailto:mjankowski at usm.maine.edu] To: mathgroup at smc.vnet.net Dear colleagues, I recently posted a question about the apparent change to Plot in version 5. I gather from the responses (thank you) that this new feature seemed natural or even desirable. That surprised me, so let me explain. I used Plot[UnitStep[x], {x, -1, 5}]; and found that Mathematica chose to display the function in the "more interesting" range of -1<=x<=1. My opinion is that an EXPLICITLY given range in any of the graphics commands should not be overridden, under any circumstances. Is there anyone who agrees with me? I would love to hear some of the opinions for and against, especially the former, because I can't think of any. Finally, if this indeed is a new feature, can anyone explain the algorithm that is used to choose the "interesting" interval and is it used in any other 2D graphic functions, and density or contour plots? Thanks, Mariusz