Re: NInegrate Bug
- To: mathgroup at smc.vnet.net
- Subject: [mg116573] Re: NInegrate Bug
- From: Alexey <lehin.p at gmail.com>
- Date: Sun, 20 Feb 2011 05:26:10 -0500 (EST)
- References: <ijispp$2dp$1@smc.vnet.net>
On 17 =D1=84=D0=B5=D0=B2, 15:20, "Kurt TeKolste" <tekol... at fastmail.net> wrote:
> Are the conditions under which the incorrect answer is returned known so
> that a practitioner can implement a workaround of the form
>
> fixedNintegrate[function_,bounds_]:=
> =C2 If[ conditions[function],
> =C2 NIntegrate[function[t]*Sign[t],bounds],NIntegrate[function[t],bounds]]
>
> and be confident that one's analysis is not scrogged?
At least in the case of NIntegrate[Sin[x^2], {x, -5, -2}] and similar
switching symbolic preprocessing off does the trick:
In[15]:= f[x_?NumericQ] := Sin[x^2]
NIntegrate[f[x], {x, -5, -2}]
Out[16]= -0.276859
In[6]:= NIntegrate[Sin[x^2], {x, -5, -2},
Method -> {"SymbolicPreprocessing", "SymbolicProcessing" -> 0}]
Out[6]= -0.276859