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Re: compile a numerical integral

• To: mathgroup at smc.vnet.net
• Subject: [mg124560] Re: compile a numerical integral
• From: psycho_dad <s.nesseris at gmail.com>
• Date: Wed, 25 Jan 2012 07:00:04 -0500 (EST)
• Delivered-to: l-mathgroup@mail-archive0.wolfram.com
• References: <jflvvs$jr4$1@smc.vnet.net>
• Reply-to: comp.soft-sys.math.mathematica at googlegroups.com

Hi Ruth,
According to the documentation, NIntegrate already uses compile, see
tutorial/CompilingMathematicaExpressions

Quoting:
"You should realize that built-in Mathematica functions quite often themselves use Compile. Thus, for example, NIntegrate by default automatically uses Compile on the expression you tell it to integrate."

Actually, you can turn it on by just using Compiled->True, eg (I modified one of the NIntegrate examples in help):

g[x_?NumericQ] := Nest[Sin[# + Sin[2 #]] &, x, 20]
NIntegrate[g[x], {x, 0, 1}, Compiled -> True] // AbsoluteTiming
NIntegrate[g[x], {x, 0, 1}, Compiled -> False] // AbsoluteTiming

I hope it helps.

Cheers,
Savvas