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Re: Compiling a Module


Klamser <Klamser at t-online.de> wrote:
>Can anyone tell me, why compiling a module saves no time during
>execution?

It all depends on whether the module compiles wholly,
largely, or not at all to "Op Codes".

To test this, you can check your compiled modules with the
following simple utility:

   myFunctionIsOpCode[x_] := Apply[List,x][[3]]//
                             Flatten//
                             VectorQ[#,NumberQ]&

When speed is important, it is well worth tweaking your modules
so that the above function returns "True".

This tweaking is more of an art than a science, for me anyway.
When a compiled function returns "False", I examine the compiled
code (using "FullForm") for clues as to which elements the
compiler is unable to parse into op-codes.  Often, these are
harmless.  For example, Print[...] is not compiled as an
opcodes, but who cares?  So long as Print[] is used only to 
generate occasional status messages.




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