Re: Strange bug
- To: mathgroup at smc.vnet.net
- Subject: [mg53291] Re: Strange bug
- From: David Bailey <dave at Remove_Thisdbailey.co.uk>
- Date: Tue, 4 Jan 2005 03:14:04 -0500 (EST)
- References: <crb40r$akl$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Steve Gray wrote: > I have procedural function "ordermat." It works ok if the next-to-last (useless) line is there but > if I remove that one line, I get error messages due to the last line, at execution time: > > Set::write: Tag Times in Null\{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, \[LeftSkeleton]1\ > \[RightSkeleton]} is Protected. > > ("intersect" returns a small integer and computes "tafr.") > > I've seen bugs like this before. I'm using 5.0.1.0 with Windows. Any clues? Thanks in advance. > > Steve Gray > > > > ordermat[gon_] := Module[{row, rx, cx}, > gonl = Length[gon]; > matx = Table[0, {i, 1, gonl}, {j, 1, gonl}]; > gona = Join[gon, gon]; > For [ rx = 1, rx <= gonl, rx++, > row = Table[0, {2*gonl}]; > row[[rx]] = 1; > row[[rx + 1]] = 2; > ab = gona[[rx]]; > ae = gona[[rx + 1]]; > For [ cx = 1, cx <= gonl - 3, cx++, > bb = gona[[cx + rx + 1]]; > be = gona[[cx + rx + 2]]; > int = intersect[ab, ae, bb, be]; > If [ int == 3, row[[cx + rx + 1]] = tafr + 1]; > ] > rx; (* Error unless some expression is here.?? *) > matx[[rx]] = Table[Max[row[[i]], row[[i + gonl]]], {i, gonl}]; > ] > ] > Hi, The 'bug' lies in the previous line of your code - you need a semicolon on the end of the line! David Bailey dbaileyconsultancy.co.uk