Skip to main content

export - Why does this simple program leak memory?


I have a simple Mathematica program which writes some plots to image files for later conversion into a movie. Unfortunately, the program leaks so much memory that it quickly exhausts all 12G of RAM on my machine. The only way out is to quit the kernel(s).


I can't see why this program shouldn't use a bounded amount of memory. I've read through Debugging memory leaks which unfortunately hasn't helped - the only "heavy" symbol is 'data', whose size is fixed. I don't see what's growing!


Note that the same problem occurs regardless of whether the loop is Map or Do, Parallel- or not. The problem also occurs in both Mathematica 8 and 9, both under Linux.


Help?


(* number of frames *)
n = 1000;

(* just some bogus data *)
makeData[_] := Table[{{x, y} = RandomReal[{-3, 3}, {2}], {y, -x}}, {200}];
data = Array[makeData, n];
(* Export the frames *)
ParallelMap[
  Export[
    "movie-" <> IntegerString[#, 10, 4] <> ".png",
    ListVectorPlot[data[[#]]]] &,
  Range[1, n]];


Edit:
Some more information: after running this code (the non-parallel version), I checked the memory usage of the processes involved. The percentages are out of 12GB, so both the frontend and the kernel are consuming quite a bit of memory, while PNG.exe is almost nonexistent.


  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND            
24575 gredner   20   0  4400  740  588 S    0  0.0   0:00.00 Mathematica        
24646 gredner   20   0 3029m 2.3g  22m S    0 20.5   1:43.02 Mathematica        
24655 gredner   20   0 3384m 1.6g  14m S    0 13.7   3:31.47 MathKernel         
24984 gredner   20   0  387m 7364 2464 S    0  0.1   0:20.92 PNG.exe


Comments

Post a Comment

Popular posts from this blog

functions - Get leading series expansion term?

Given a function f[x] , I would like to have a function leadingSeries that returns just the leading term in the series around x=0 . For example: leadingSeries[(1/x + 2)/(4 + 1/x^2 + x)] x and leadingSeries[(1/x + 2 + (1 - 1/x^3)/4)/(4 + x)] -(1/(16 x^3)) Is there such a function in Mathematica? Or maybe one can implement it efficiently? EDIT I finally went with the following implementation, based on Carl Woll 's answer: lds[ex_,x_]:=( (ex/.x->(x+O[x]^2))/.SeriesData[U_,Z_,L_List,Mi_,Ma_,De_]:>SeriesData[U,Z,{L[[1]]},Mi,Mi+1,De]//Quiet//Normal) The advantage is, that this one also properly works with functions whose leading term is a constant: lds[Exp[x],x] 1 Answer Update 1 Updated to eliminate SeriesData and to not return additional terms Perhaps you could use: leadingSeries[expr_, x_] := Normal[expr /. x->(x+O[x]^2) /. a_List :> Take[a, 1]] Then for your examples: leadingSeries[(1/x + 2)/(4 + 1/x^2 + x), x] leadingSeries[Exp[x], x] leadingSeries[(1/x + 2 + (1 - 1/x...
Post a Comment
Read more

How to thread a list

I have data in format data = {{a1, a2}, {b1, b2}, {c1, c2}, {d1, d2}} Tableform: I want to thread it to : tdata = {{{a1, b1}, {a2, b2}}, {{a1, c1}, {a2, c2}}, {{a1, d1}, {a2, d2}}} Tableform: And I would like to do better then pseudofunction[n_] := Transpose[{data2[[1]], data2[[n]]}]; SetAttributes[pseudofunction, Listable]; Range[2, 4] // pseudofunction Here is my benchmark data, where data3 is normal sample of real data. data3 = Drop[ExcelWorkBook[[Column1 ;; Column4]], None, 1]; data2 = {a #, b #, c #, d #} & /@ Range[1, 10^5]; data = RandomReal[{0, 1}, {10^6, 4}]; Here is my benchmark code kptnw[list_] := Transpose[{Table[First@#, {Length@# - 1}], Rest@#}, {3, 1, 2}] &@list kptnw2[list_] := Transpose[{ConstantArray[First@#, Length@# - 1], Rest@#}, {3, 1, 2}] &@list OleksandrR[list_] := Flatten[Outer[List, List@First[list], Rest[list], 1], {{2}, {1, 4}}] paradox2[list_] := Partition[Riffle[list[[1]], #], 2] & /@ Drop[list, 1] RM[list_] := FoldList[Transpose[{First@li...
Post a Comment
Read more

front end - keyboard shortcut to invoke Insert new matrix

I frequently need to type in some matrices, and the menu command Insert > Table/Matrix > New... allows matrices with lines drawn between columns and rows, which is very helpful. I would like to make a keyboard shortcut for it, but cannot find the relevant frontend token command (4209405) for it. Since the FullForm[] and InputForm[] of matrices with lines drawn between rows and columns is the same as those without lines, it's hard to do this via 3rd party system-wide text expanders (e.g. autohotkey or atext on mac). How does one assign a keyboard shortcut for the menu item Insert > Table/Matrix > New... , preferably using only mathematica? Thanks! Answer In the MenuSetup.tr (for linux located in the $InstallationDirectory/SystemFiles/FrontEnd/TextResources/X/ directory), I changed the line MenuItem["&New...", "CreateGridBoxDialog"] to read MenuItem["&New...", "CreateGridBoxDialog", MenuKey["m", Modifiers-...
Post a Comment
Read more