Re: $Assumptions
- To: mathgroup at smc.vnet.net
- Subject: [mg92639] Re: $Assumptions
- From: Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com>
- Date: Thu, 9 Oct 2008 06:35:57 -0400 (EDT)
- Organization: The Open University, Milton Keynes, UK
- References: <gci2ia$ta$1@smc.vnet.net>
Ruth Lazkoz Sáez wrote:
> I seem to be unable to change some default options globally.
>
> At the top of my notebook I have
>
> $Assumptions = {MaxRecursion -> 30, AccuracyGoal -> 10};
>
> Then we I evaluate NIntegrate[Exp[-x^2], {x, 20., 40.}]
> I get 4.78196*10^-176
>
> But if I evaluate NIntegrate[Exp[-x^2], {x, 20., 40.}, MaxRecursion -> 30,
> AccuracyGoal -> 10]
> I get quite a different value, 1.36703*10^-177
>
> I had the same problem trying to change the options for fonts in plots,
> and then I had to add the options I wanted
> in every plot, I mean evaluation something like $TextStyle ={whatever}
> before doing the plots did not work.
What you want is *SetOptions* (Note that $Assumptions has nothing to do
with options but with assumptions such as x > 0 or Element[n, Integers])
In[166]:=
SetOptions[NIntegrate, {MaxRecursion -> 30, AccuracyGoal -> 10}];
NIntegrate[Exp[-x^2], {x, 20., 40.}]
Out[167]= 1.36703*10^-177
Regards,
-- Jean-Marc