MathGroup Archive 2010

[Date Index] [Thread Index] [Author Index]

Search the Archive

RootSearch issue


Hi. This is an strange issue I'm having with v1.4 of Ersek's RootSearch 
package. I'm looking for the roots of a function and it so happens that 
if I specify a small interval, it finds the roots, but when I increase 
the interval, it doesn't find any root!. Specifically, here's a code 
sample:

In[39]:= \[Gamma]even[r_, k_, e_] :=
  I MathieuCPrime[MathieuCharacteristicA[r, k^2/4], k^2/4,
    I ArcTanh[Sqrt[1 - e^2]]];
rootsEven[r_, e_, {kmin_, kmax_}, opts : OptionsPattern[]] :=
 RootSearch[\[Gamma]even[r, k, e] == 0, {k, kmin, kmax}, opts] // Quiet

In[38]:= rootsEven[4, 5/20, {0, 10}][[All, 1, 2]]

Out[38]= {1.35064, 2.3571, 3.21912}

In[36]:= rootsEven[4, 5/20, {0, 100}][[All, 1, 2]]

Out[36]= {1.35064, 2.3571, 3.21912}

In[35]:= rootsEven[4, 5/20, {0, 1000}][[All, 1, 2]]

Out[35]= {}



Is there an explanation for this? Thanks.


  • Prev by Date: Re: Row or column?
  • Next by Date: Re: How do I test for existence of a list element?
  • Previous by thread: Re: Mathematica calculates RSquared wrongly?
  • Next by thread: Re: RootSearch issue