[Date Index]
[Thread Index]
[Author Index]
Re: compile a numerical integral
*To*: mathgroup at smc.vnet.net
*Subject*: [mg124581] Re: compile a numerical integral
*From*: Bill Rowe <readnews at sbcglobal.net>
*Date*: Wed, 25 Jan 2012 07:07:21 -0500 (EST)
*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com
On 1/24/12 at 5:07 AM, ruth.lazkoz at ehu.es (Ruth Lazkoz S=C3=A1ez) wrote:
>I am working to make a code faster using compile and failed at the
>very beginning. Is there a way to make a version that works?
>f=Compile[{u},NIntegrate[x*u,{x,0.,#}]&/@{1,2,3}]
Try,
f = Compile[{{u, _Real}, {a, _Real}}, NIntegrate[u x, {x, 0, a}]]
But, while this compiles, it would be very surprising if there
were any measurable improvement in execution speed. Compile
cannot optimize built-in functions. Calls to built-in functions
already call compiled code. What Compile can do is Compile an
Mathematica expression. That is:
u*x
could be compiled by Compile. But, it is very unlikely you will
see any significant improvement for such a simple expression.
You would almost certainly get better performance by doing
In[2]:= int = Integrate[u x, {x, 0, a}]
Out[2]= (a^2*u)/2
and then supplying numeric values for u,a.
or by doing:
g = Compile[{{u, _Real}, {a, _Real}},
Evaluate[Integrate[u x, {x, 0, a}]]]
That is telling Mathematica to evaluate the integral
symbolically then compile the result.
Prev by Date:
**Using same pure function for curve and surface mappings**
Next by Date:
**Mapping Bezier curve to surface. Locator problem, still.**
Previous by thread:
**Re: compile a numerical integral**
Next by thread:
**Re: compile a numerical integral**
| |