Arbitrary Crash with Compile

*To*: mathgroup at smc.vnet.net*Subject*: [mg36478] Arbitrary Crash with Compile*From*: Wizard Lab <cschmitt at wizard.ucr.edu>*Date*: Sun, 8 Sep 2002 03:31:06 -0400 (EDT)*Organization*: University of California, Riverside*Sender*: owner-wri-mathgroup at wolfram.com

Dear Group, I have a program to take the local polynomial non parametric regression of two variables. It uses Compile, unfortunately, and regularly, but inconsistently, causes Mathematica to crash (in Win2K, with I forget what error, and in Win98/Mathematica4.0 with an invalid memory access from MathDLL.dll). I am running Mathematica 4.1, and have this problem consistently on 4 different machines. Here is the code, if it doesn't crash the first time, it will the second or third: (* w = Compile[{{xj, _Real, 0}, {XX, _Real, 1}, {YY, _Real, 1}, {h, _Real, 0}, {nn, _Integer, 0}, {ord, _Integer, 0}}, First[Inverse[Sum[Outer[Times, Table[If[Positive[q], (XX[[i]] - xj)^q, 1], {q, 0, ord}], Table[If[Positive[q], (XX[[i]] - xj)^q, 1.], {q, 0, ord}]*E^(-0.5*((XX[[i]] - xj)/h)^2)], {i, nn}]] . Sum[(Table[If[Positive[q], (XX[[i]] - xj)^q, 1.], {q, 0, ord}]*YY[[i]])* E^(-0.5*((XX[[i]] - xj)/h)^2), {i, nn}]]]; *) (* \!\(tt = MemoryInUse[]; ListPlot[Table[{\((i + 1)\)\^2, \(Timing[ nn = \((i + 1)\)\^2; \[Epsilon] = Table[Random[]*3, {i, nn}]; testX = Table[i* .3 - Random[]*2, {i, nn}]; testY = Table[Sin[i/3] - 2, {i, nn}] + \[Epsilon]; Map[w[#, testX, testY, .1 + Random[], nn, 0] &, testX];]\)[\([1]\)]/Second}, {i, 15}], PlotJoined -> True, PlotLabel -> "\<Calculation Times as a function of n\>"]; MemoryInUse[] - tt\) *) I have followed Ted Ersek's tips and tricks (http://www.verbeia.com/mathematica/tips/tip_index.html) about Compile, and have tried changing all variable names (works sometimes), removing any hidden spaces, restructuring the formulas, changing all 0's to 0. 's and all 1's to 1. 's, etcetera etcetera, but I still can't comprehend what the problem might be. Doing "w[[-2]]" shows a list of op-code numbers, and one function name, Inverse[#1]&, so it seems to me that there are no problems with the use of Compile here. Would anyone have any thoughts??? Regards, Bernard Gress burnthebiscuit at netscape.net