Re: Problem with compiled function (is this a bug?)

*To*: mathgroup at smc.vnet.net*Subject*: [mg65584] Re: Problem with compiled function (is this a bug?)*From*: tt at tt.com*Date*: Sun, 9 Apr 2006 04:32:09 -0400 (EDT)*Organization*: National Research Council, Ottawa, Canada*References*: <e17ffs$olg$1@smc.vnet.net>*Reply-to*: tt at tt.com*Sender*: owner-wri-mathgroup at wolfram.com

On version 5.2 Windows, your code works fine if the iterator initial values are explicitely set as Real (1->1.): cpl = Compile[{x, y}, Table[Ceiling[Norm[{i, j} - Ceiling[{x, y}/2]]], {i, 1., x}, {j, 1., y}]] Above the two iterator initial values are changed to "1.", but it does work if only one of them is changed like in: cpl = Compile[{x, y}, Table[Ceiling[Norm[{i, j} - Ceiling[{x, y}/2]]], {i, 1., x}, {j, 1, y}]] Why? I will leave that answer to others... Cordially. GL On Sat, 8 Apr 2006 04:51:08 +0000 (UTC), szhorvat at gmail.com wrote: >I have a problem with the following compiled function: > >cpl = Compile[{x,y}, Table[Ceiling[Norm[{i, j} - Ceiling[{ > x, y}/2]]], {i, 1, x}, {j, 1, y}]] > >When trying to use this function (for example, as idx = cpl[100,100]), >I get the following error: > >CompiledFunction::"cfte" : >Compiled expression 49 Sqrt[2] should be a rank 1 tensor of >machine-size integers. > >CompiledFunction::cfex: External evaluation error at instruction 23; >proceeding with uncompiled evaluation. > >I get the same error even if I try to specify that all variables are >Reals: > >cpl = Compile[{{x, _Real}, {y, _Real}}, Table[Ceiling[Norm[{i, j} - >Ceiling[{ > x, y}/2]]], {i, 1, x}, {j, 1, y}], {{i, _Real}, {j, _Real}}] > >Is this a bug in Mathematica? If not, what is the right way to compile >this function? Does this error occur with earlier versions than 5.2? > >I'd like to use this function to generate indices for a matrix whose >values I want to average radially (ie. I'd like to compute the mean >values in the ring around the center of the matrix). Unofrtunately this >function takes more than 16 seconds on an 500x500 matrix on my machine >which seems unrealistically long for such a simple function. I need to >use the function interactively on many datasets, often much larger than >500x500. > >Szabolcs Horvat