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Re: FindRoot + Compile = incompatible (?)

• To: mathgroup at smc.vnet.net
• Subject: [mg111309] Re: FindRoot + Compile = incompatible (?)
• From: Mark Adler <madler at alumni.caltech.edu>
• Date: Tue, 27 Jul 2010 04:16:53 -0400 (EDT)
• References: <i2joiv$fsk$1@smc.vnet.net>

On 2010-07-26 03:38:23 -0700, Scot T. Martin said:
> Anyone have thoughts on how to work around this aspect so that
> Compile'd functions can work within FindRoot and thus accelerate
> evaluation thereof?

FindRoot already compiles, which may be why you're not seeing a
difference.  Try FindRoot[uncompiled expression, ..., Compiled->False]
and see if it's slower than FindRoot[uncompiled expression, ...].

If you want to pre-compile, you can just turn the message off with
Off[CompiledFunction::cfsa].  The message is just a performance
warning, since when it is issued, it uses the symbolic expression to
get the correct answer anyway.  It must only be calling the function
once with symbolic arguments, since otherwise you'd see that message
three times.

Mark