Re: Re: bad Mathieu functions
- To: mathgroup at smc.vnet.net
- Subject: [mg108312] Re: [mg108291] Re: bad Mathieu functions
- From: DrMajorBob <btreat1 at austin.rr.com>
- Date: Sat, 13 Mar 2010 07:57:39 -0500 (EST)
- References: <hnakhc$5p5$1@smc.vnet.net> <201003121214.HAA13890@smc.vnet.net>
- Reply-to: drmajorbob at yahoo.com
Or, a trifle simpler:
ce1[r_, q_, z_] := MathieuCPrime[MathieuCharacteristicA[r, q], q, z]
Plot[I ce1[3, SetPrecision[qq, 123], I], {qq, 750, 1000},
Frame -> True, Axes -> None]
or simpler yet:
Plot[I ce1[3, qq, I], {qq, 750, 1000}, Frame -> True, Axes -> None,
WorkingPrecision -> 123]
Note that this doesn't work at all, and it's much slower:
ce1[r_, q_, z_] :=
MathieuCPrime[MathieuCharacteristicA[r, SetPrecision[q, 123]], q, z]
Plot[I ce1[3, qq, I], {qq, 750, 1000}, Frame -> True, Axes -> None]
Does anyone have a clue why that is?
Bobby
On Fri, 12 Mar 2010 06:14:16 -0600, Peter Pein <petsie at dordos.net> wrote:
> Am 11.03.2010 12:35, schrieb becko BECKO:
>> I am no expert in Mathieu functions, but I don't think this gives the
>> right result:
>>
>> ce1[r_, q_, z_] := MathieuCPrime[MathieuCharacteristicA[r, q], q, z]
>>
>> Plot[I ce1[3, q, I], {q, 0, 1000}]
>>
>>
>> In another system you get a smooth graph, making very small
>> oscillations about zer o as q increases.
> ...
>
> Oh yes, these oscillations are really tiny as you can see with
> Mathematica using:
>
> Plot[I ce1[3,q,I] /. q->SetPrecision[qq,123], {qq, 750, 1000},
> Frame->True, Axes->None]
>
>
--
DrMajorBob at yahoo.com
- References:
- Re: bad Mathieu functions
- From: Peter Pein <petsie@dordos.net>
- Re: bad Mathieu functions