Behaviour of Plot/ListPlot & Export

*To*: mathgroup at smc.vnet.net*Subject*: [mg31722] Behaviour of Plot/ListPlot & Export*From*: SteveC <steve at fractalus.com>*Date*: Thu, 29 Nov 2001 00:13:41 -0500 (EST)*Sender*: owner-wri-mathgroup at wolfram.com

Mathematica 4.1.1.0 on Linux If I try Plot[Sqrt[Prime[n]/Prime[n + 1]], {n, 1, 100}] I get: Prime::"intpp": "Positive integer argument expected in \ \!\(Prime[1.000004125`]\)." Prime::"intpp": "Positive integer argument expected in \ \!\(Prime[1.000004125`]\)." Prime::"intpp": "Positive integer argument expected in \ Prime[2.0000041250000002`]." And a bunch more errors, however if I try ListPlot[Table[Sqrt[Prime[n]/Prime[n + 1]], {n, 1, 100}]] Then it works fine. Presumably Table[x,{x,1,100}] steps through integers while Plot does not. This is surprising, I expected the same behaviour of them. Is this a bug? Is this documented (I did look around)? I have been doing a lot of work with Export[]ing single cells and animated Gifs. I find Mathematica on something like Export["somefile.gif",Table[<big list of graphics>]] will produce the graphics and then export individual frames to /tmp/m<some number> as PNM files *incredibly* slowly. It will take 3 minutes per image and they are not complex images. The CPU is not utilised during that time, only in small bursts, wait a few minutes then do the next. For 100 cell animations this is frustrating. The process tree has PNM.exe and GIF.exe running but doing nothing. Perhaps they are timing out on some operation? I could run traces for the truely interested... Once it has exported all the images it appears to then keep them all in memory before creating the GIF. I recently had a 600 frame animation [I appreciate this should be in an mpeg, and I did so] where mathematica used 1 Gigabyte of memory plus 128 meg of swap before the kernel VM killed it for eating all available resources. I respectfully suggest this architecture is flawed. I am now using ImageMagick for all of these operations. :-/ Also, Mathematica has a bug that I submitted where it crashes on changing some prefs which was confirmed. As an aside is there a version release > than mine and if so am I able to obtain it? tia SteveC steve at fractalus.com fractalus.com/steve