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[MUG] dsolve[numeric] output order
| [MUG] dsolve[numeric] output order |
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Author: Andris Lasis/Sim S S Service Centre
Posted: 01/03/2000 09:14:25 GMT
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>> From: "Andris Lasis/Sim.S.S. Service Centre"
Hello MUG,
when solving large systems of DEs numerically, I encouraged a problem
that makes me mad. There are multiple functions dependent on one
variable t as:
x1(t)...xn(t). When I solve that kind of system and evaluate it as
> f:=dsolve(......,{x1(t)...xn(t)},type=numeric,output=listprocedure):
> f(10);
I get the array of [t=2, x1(t)=smthng,...xn(t)=smthng,....]
Every time I start a new session of Maple and solve this system, I get
different ordered array. Sometimes it starts with [t=2,x3(t)=..],
sometimes from the other value, and all the x(t)'s are mixed.
It is extremely important to me to get the array of equal order whenever
I evaluate this f again.
I reviewed help and MUG answers - no success...
One of course could make filtering of array etc., but I believe there is
simpler method to get normally, not randomly ordered array.
Thank you in advance.
--
Best regards,
Andris Lasis
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| [MUG] Re: dsolve[numeric] output order |
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Author: Maple Group
Posted: 09/03/2000 13:42:09 GMT
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Subject: dsolve[numeric] output order
t is an independent variable and x1(t),..., xn(t) are dependent
variables in your differential equations. If you specify
x1(t),..., xn(t) by type of list instead of set, you get the order
you want. For example,
using
dsolve({syseqns}, [x1(t), x2(t), x3(t)], ..., output=listprocedure);
NOT
dsolve({syseqns}, {x1(t), x2(t), x3(t)}, ..., output=listprocedure);
-Xianping
------------------------------------------------------------------
Xianping Liu |
Dept. of Computer Science |
Univ. of Waterloo | 306-87 Westwood Dr.
Waterloo, Ontario, Canada | Kitchener, Ontario, Canada
N2L 3G1 | N2M 2K7
Phone (519)888-4567 x5435(O) | Phone/Fax (519)584-7067(H)
email:
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From: Andre Poenitz
Subject: dsolve[numeric] output order
To:
Date: Tue, 7 Mar 2000 08:25:17 +0100 (MET)
> I get the array of [t=2, x1(t)=smthng,...xn(t)=smthng,....]
What happens if you apply 'sort' to this list? It should at least
reduce the amount of randomness.
Andre'
--
It'll take a long time to eat 63.000 peanuts.
Andre Poenitz .........................
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Date: Tue, 07 Mar 2000 10:04:45 +0100 (CET)
From:
To:
Subject: dsolve[numeric] output order
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