Skip to main content

version 10 - In Compile "InlineExternalDefinitions" doesn't work anymore in Mma v10 like in v9


In Mma 9 using CompilationOptions -> {"InlineExternalDefinitions" -> True} inside of Compile inlined the values of the previously defined parameters used in the function to be compiled.


For example:


nPara = 3;
cf = Compile[{{x, _Real, 1}},
  Sum[x[[i]], {i, nPara}], 
  CompilationOptions -> {"InlineExternalDefinitions" -> True}

  ]

resultes in:


Output Mma9


and works flawless as expected.


But in Mma 10 the output is:


Output Mma10


And, as now the value of nPara is not known to the compiled function, the comiled function doesn't work anymore.


For such a simple function one can apply Whith as a workaround:


With[{nPara = nPara},

 Compile[{{x, _Real, 1}},
  Sum[x[[i]], {i, nPara}], 
  CompilationOptions -> {"InlineExternalDefinitions" -> True}
  ]
 ]

However, in bigger notebooks and with more complex functions this undocumented code break (or is a bug or a fix) causes bigger issues.


Does anyone know a more convenient or automated workaround to fix this problem?



Answer



It is unfortunate that this no longer works. I like metaprogramming, and I felt that inlining variables is a nice exercise, so I can share some functions with you that make things easier.



Your approach using With seems reasonable. I also saw you test an example using Evaluate, but relying on the fact that x[[i]] evaluates to x[[i]] if i not an integer and x has no value is quite bad.


You say that your approach using With will not work for more complicated cases. If the issue is that you want to use evaluation to determine the values of your parameters, you can use the following.


ClearAll@inlineEval
SetAttributes[inlineEval, HoldAll];
inlineEval[expr_, symbols__] :=
 Unevaluated[expr] /. 
  Thread[Rule[HoldPattern /@ Unevaluated[{symbols}], {symbols}]]

You can use it as follows. Let's set up a situation that is relatively hard to deal with to test it.


b := c[1, 2]

c[x_, y_] := x + y

Now we can do


cfu =
  inlineEval[
   Compile[{{x, _Integer}}, Sum[1, {i, x + b}]]
   ,
   b
   ];
cfu[3]



6

If you don't want to use evaluation, you can use the following.


SetAttributes[inlineAll, HoldAll]
inlineAll[expr_, symbols__Symbol] :=
  ReleaseHold[
   HoldComplete[expr] //.
    Flatten[Function[Null, {OwnValues@#, DownValues@#}, HoldAll] /@ 

      Unevaluated[{symbols}]]
   ];

Now you can also this, but note that you have to specify that c has to be inlined as well.


cfu2 =
  inlineAll[
   Compile[{{x, _Integer}}, Sum[1, {i, x + b}]]
   ,
   b, c
   ];

cfu2[3]


6

Note that both functions also with symbols that have DownValues, which is something I believe "InlineExternalDefinitions" could not deal with to begin with. The previous examples dealt only with constants, but here is an example where we inline a function.


f[x_] := Norm[x];
cfu3 =
  inlineAll[
   Compile[{{x, _Real, 1}}, f[x] + 3]

   ,
   f
   ];
cfu3[{1., 1.}] == Sqrt[2] + 3


True

This technique allows you to make large compiled functions, while maintaining readability. You could imagine that when compiled functions get too large, you simply let one compiled function call another compiled function, and optionally using "InlineCompiledFunctions". But I like this alternative :).


Related (but probably less nice than this)



Comments

Post a Comment

Popular posts from this blog

mathematical optimization - Minimizing using indices, error: Part::pkspec1: The expression cannot be used as a part specification

I want to use Minimize where the variables to minimize are indices pointing into an array. Here a MWE that hopefully shows what my problem is. vars = u@# & /@ Range[3]; cons = Flatten@ { Table[(u[j] != #) & /@ vars[[j + 1 ;; -1]], {j, 1, 3 - 1}], 1 vec1 = {1, 2, 3}; vec2 = {1, 2, 3}; Minimize[{Total@((vec1[[#]] - vec2[[u[#]]])^2 & /@ Range[1, 3]), cons}, vars, Integers] The error I get: Part::pkspec1: The expression u[1] cannot be used as a part specification. >> Answer Ok, it seems that one can get around Mathematica trying to evaluate vec2[[u[1]]] too early by using the function Indexed[vec2,u[1]] . The working MWE would then look like the following: vars = u@# & /@ Range[3]; cons = Flatten@{ Table[(u[j] != #) & /@ vars[[j + 1 ;; -1]], {j, 1, 3 - 1}], 1 vec1 = {1, 2, 3}; vec2 = {1, 2, 3}; NMinimize[ {Total@((vec1[[#]] - Indexed[vec2, u[#]])^2 & /@ R...
Post a Comment
Read more

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 remap graph properties?

Graph objects support both custom properties, which do not have special meanings, and standard properties, which may be used by some functions. When importing from formats such as GraphML, we usually get a result with custom properties. What is the simplest way to remap one property to another, e.g. to remap a custom property to a standard one so it can be used with various functions? Example: Let's get Zachary's karate club network with edge weights and vertex names from here: http://nexus.igraph.org/api/dataset_info?id=1&format=html g = Import[ "http://nexus.igraph.org/api/dataset?id=1&format=GraphML", {"ZIP", "karate.GraphML"}] I can remap "name" to VertexLabels and "weights" to EdgeWeight like this: sp[prop_][g_] := SetProperty[g, prop] g2 = g // sp[EdgeWeight -> (PropertyValue[{g, #}, "weight"] & /@ EdgeList[g])] // sp[VertexLabels -> (# -> PropertyValue[{g, #}, "name"]...
Post a Comment
Read more