Groups > sci.physics.relativity > #384755

Re: Interesting problem

From	Odd Bodkin <bodkinodd@gmail.com>
Newsgroups	sci.physics.relativity
Subject	Re: Interesting problem
Date	2016-06-01 11:11 -0500
Organization	Aioe.org NNTP Server
Message-ID	<nin1fq$1j46$1@gioia.aioe.org> (permalink)
References	(16 earlier) <niflaf$cf4$1@gioia.aioe.org> <61d916ae-3ee6-4360-94c4-dd4b9c6ca6cf@googlegroups.com> <d0b149ff-b994-4498-a1f3-ea4549b88f3f@googlegroups.com> <nikrsa$1q22$1@gioia.aioe.org> <302cf2aa-9074-4b3f-95f0-2b76983d4528@googlegroups.com>

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On 6/1/2016 8:23 AM, Prokaryotic Caspase Homolog wrote:
> On Tuesday, May 31, 2016 at 3:23:45 PM UTC-5, HGWilson, DSc. wrote:
>> On 31/05/16 21:25, Prokaryotic Caspase Homolog wrote:
>
>>> Henry, please try using a PROVEN solution instead of attempting to make up your
>>> own ad hoc fix. Many, many people have devoted thousands of man-years in the
>>> development of accurate, reliable and stable techniques for numerically solving
>>> differential equations.
>>
>> They didn't have double precision numbers and fast computers.
>> I have given up differential equations altogether.
>
> No you haven't. In a previous post, you wrote:
>    "In the x direction, the simplest iteration for each time unit uses
>     v=v+a: x=x+v: a= fn(x), (same for y), repeat"
>
> This is the classic Euler method for solving ordinary differential equations.
>
> The Euler method is a first order method, the simplest and most primitive.
> An easy step up would be a second order method. I'll post one for you later,
> but I have to be getting to work right now.
>
>> Real situations are
>> never exact anyway. It is much easier to simulate and produce a series
>> of graphs directly.
>>
>> I can easily correct my ellipses by doing what I just
>> suggested....monitoring the error and applying a factor throughout the
>> iteration until the error is minimized.
>
> That is pretty much what most advanced methods do: take a step, figure out
> an estimate for the error, and then take a revised step based on what you've
> found out.
>
> Later...
>

I think you're going to find that Henry's capacity or interest in doing 
anything better than what he's already done is limited at best. Henry 
complains constantly that relativity should be disparaged because it is 
more complicated than the 19th century physics he knows. Likewise, when 
it comes to computational methods, he's going to be happy with 
first-order solution plus ad hoc tweak, because anything more 
complicated than that is just above his level of commitment.

-- 
Odd Bodkin --- maker of fine toys, tools, tables

Thread

Interesting problem "HGWilson, DSc." <hgw@....> - 2016-05-26 07:05 +1000
  Re: Interesting problem Poutnik <poutnik4nntp@gmail.com> - 2016-05-25 23:17 +0200
    Re: Interesting problem "David (Time Lord) Fuller" <fuller.david@hotmail.com> - 2016-05-25 14:20 -0700
  Re: Interesting problem "David (Time Lord) Fuller" <fuller.david@hotmail.com> - 2016-05-25 14:18 -0700
  Re: Interesting problem Odd Bodkin <bodkinodd@gmail.com> - 2016-05-25 16:20 -0500
    Re: Interesting problem Tom Roberts <tjroberts137@sbcglobal.net> - 2016-05-25 18:31 -0500
    Re: Interesting problem "HGWilson, DSc." <hgw@....> - 2016-05-27 03:25 +1000
      Re: Interesting problem Odd Bodkin <bodkinodd@gmail.com> - 2016-05-26 13:32 -0500
        Re: Interesting problem HGW <hw@...> - 2016-05-27 12:15 +1000
          Re: Interesting problem Odd Bodkin <bodkinodd@gmail.com> - 2016-05-27 04:26 -0500
            Re: Interesting problem "HGWilson, DSc." <hgw@....> - 2016-05-27 19:52 +1000
              Re: Interesting problem Odd Bodkin <bodkinodd@gmail.com> - 2016-05-27 05:46 -0500
                Re: Interesting problem "HGWilson, DSc." <hgw@....> - 2016-05-27 21:55 +1000
                Re: Interesting problem Odd Bodkin <bodkinodd@gmail.com> - 2016-05-27 07:23 -0500
                Re: Interesting problem Odd Bodkin <bodkinodd@gmail.com> - 2016-05-27 07:26 -0500
                Re: Interesting problem "David (Time Lord) Fuller" <fuller.david@hotmail.com> - 2016-05-27 05:29 -0700
                Re: Interesting problem "HGWilson, DSc." <hgw@....> - 2016-05-28 19:47 +1000
                Re: Interesting problem Prokaryotic Caspase Homolog <prokaryotic.caspase.homolog@gmail.com> - 2016-05-28 04:12 -0700
                Re: Interesting problem Prokaryotic Caspase Homolog <prokaryotic.caspase.homolog@gmail.com> - 2016-05-28 04:51 -0700
                Re: Interesting problem alsor@interia.pl - 2016-05-28 11:27 -0700
                Re: Interesting problem Prokaryotic Caspase Homolog <prokaryotic.caspase.homolog@gmail.com> - 2016-05-28 14:01 -0700
                Re: Interesting problem alsor@interia.pl - 2016-05-28 15:10 -0700
                Re: Interesting problem "HGWilson, DSc." <hgw@....> - 2016-05-29 09:35 +1000
                Re: Interesting problem alsor@interia.pl - 2016-05-29 10:35 -0700
                Re: Interesting problem "HGWilson, DSc." <hgw@....> - 2016-05-30 07:01 +1000
                Re: Interesting problem Prokaryotic Caspase Homolog <prokaryotic.caspase.homolog@gmail.com> - 2016-05-29 15:22 -0700
                Re: Interesting problem alsor@interia.pl - 2016-05-30 13:05 -0700
                Re: Interesting problem alsor@interia.pl - 2016-05-30 16:27 -0700
                Re: Interesting problem "HGWilson, DSc." <hgw@....> - 2016-05-31 20:56 +1000
                Re: Interesting problem alsor@interia.pl - 2016-05-31 08:40 -0700
                Re: Interesting problem HGW <hw@...> - 2016-06-02 09:40 +1000
                Re: Interesting problem alsor@interia.pl - 2016-06-02 11:53 -0700
                Re: Interesting problem Prokaryotic Caspase Homolog <prokaryotic.caspase.homolog@gmail.com> - 2016-05-31 04:25 -0700
                Re: Interesting problem mlwozniak@wp.pl - 2016-05-31 04:58 -0700
                Re: Interesting problem "HGWilson, DSc." <hgw@....> - 2016-06-01 06:31 +1000
                Re: Interesting problem Odd Bodkin <bodkinodd@gmail.com> - 2016-05-31 16:30 -0500
                Re: Interesting problem HGW <hw@...> - 2016-06-02 09:44 +1000
                Re: Interesting problem JanPB <filmart@gmail.com> - 2016-05-31 14:58 -0700
                Re: Interesting problem "HGWilson, DSc." <hgw@....> - 2016-06-01 06:24 +1000
                Re: Interesting problem Prokaryotic Caspase Homolog <prokaryotic.caspase.homolog@gmail.com> - 2016-06-01 06:23 -0700
                Re: Interesting problem Odd Bodkin <bodkinodd@gmail.com> - 2016-06-01 11:11 -0500
                Re: Interesting problem HGW <hw@...> - 2016-06-02 09:47 +1000
                Re: Interesting problem Prokaryotic Caspase Homolog <prokaryotic.caspase.homolog@gmail.com> - 2016-06-01 18:50 -0700
                Re: Interesting problem alsor@interia.pl - 2016-06-02 12:07 -0700
                Re: Interesting problem alsor@interia.pl - 2016-06-01 08:59 -0700
                Re: Interesting problem HGW <hw@...> - 2016-06-02 10:09 +1000
                Re: Interesting problem Odd Bodkin <bodkinodd@gmail.com> - 2016-05-29 13:52 -0500
                Re: Interesting problem "HGWilson, DSc." <hgw@....> - 2016-05-30 07:09 +1000
                Re: Interesting problem Sam Wormley <swormley1@gmail.com> - 2016-05-29 16:26 -0500
                Re: Interesting problem Fabian Russell <fb@zen.info> - 2016-05-30 04:25 +0000
                Re: Interesting problem "HGWilson, DSc." <hgw@....> - 2016-05-31 21:00 +1000
                Re: Interesting problem Fabian Russell <fb@zen.info> - 2016-05-31 22:46 +0000
                Re: Interesting problem HGW <hw@...> - 2016-06-02 09:32 +1000
                Re: Interesting problem Prokaryotic Caspase Homolog <prokaryotic.caspase.homolog@gmail.com> - 2016-05-27 05:34 -0700
                Re: Interesting problem "David (Time Lord) Fuller" <fuller.david@hotmail.com> - 2016-05-27 05:40 -0700
                Re: Interesting problem "David (Time Lord) Fuller" <fuller.david@hotmail.com> - 2016-05-27 05:43 -0700
                Re: Interesting problem rotchm <rotchm@gmail.com> - 2016-05-27 06:40 -0700
                Re: Interesting problem Prokaryotic Caspase Homolog <prokaryotic.caspase.homolog@gmail.com> - 2016-05-27 07:42 -0700
                Re: Interesting problem rotchm <rotchm@gmail.com> - 2016-05-27 06:36 -0700
                Re: Interesting problem Odd Bodkin <bodkinodd@gmail.com> - 2016-05-27 09:01 -0500
                Re: Interesting problem "HGWilson, DSc." <hgw@....> - 2016-05-28 20:04 +1000
                Re: Interesting problem Prokaryotic Caspase Homolog <prokaryotic.caspase.homolog@gmail.com> - 2016-05-28 04:34 -0700
    Re: Interesting problem Fabian Russell <fb@zen.info> - 2016-05-27 22:03 +0000
      Re: Interesting problem "HGWilson, DSc." <hgw@....> - 2016-05-28 20:10 +1000

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