MATLAB Central Newsreader - Solve Array of symbolic functions

Solve Array of symbolic functions

Quint Segers — Tue, 30 Oct 2007 15:03:24 -0400

if A1 is an array of symbolic funtions:
A1=
              -a1+a2-a3+a4
-1/27*a1+1/9*a2-1/3*a3+a4
  1/27*a1+1/9*a2+1/3*a3+a4
               a1+a2+a3+a4

Why can't I use solve like:

[a1, a2, a3, a4] = solve('A1(1)=1', 'A1(2)=0', 'A1(3)
=0', 'A1(4)=0', a1, a2, a3, a4);

But must I manually insert all the values of A1 like this?:

[a1, a2, a3, a4] = solve('-a1+a2-a3+a4=1', '-1/27*a1+1/9*a2-
1/3*a3+a4=0', '1/27*a1+1/9*a2+1/3*a3+a4=0', 'a1+a2+a3+a4=0',
a1, a2, a3, a4)[a1, a2, a3, a4] = solve('-a1+a2-
a3+a4=1', '-1/27*a1+1/9*a2-
1/3*a3+a4=0', '1/27*a1+1/9*a2+1/3*a3+a4=0', 'a1+a2+a3+a4=0',
a1, a2, a3, a4)

Re: Solve Array of symbolic functions

roberson@ibd.nrc-cnrc.gc.ca (Walter Roberson) — Tue, 30 Oct 2007 16:06:18 -0400

In article <fg7h3s$mk1$1@fred.mathworks.com>,
Quint Segers <q.segers@gmail.com> wrote:
>if A1 is an array of symbolic funtions:
>A1=
> -a1+a2-a3+a4
> -1/27*a1+1/9*a2-1/3*a3+a4
> 1/27*a1+1/9*a2+1/3*a3+a4
> a1+a2+a3+a4
>
>Why can't I use solve like:
>
>[a1, a2, a3, a4] = solve('A1(1)=1', 'A1(2)=0', 'A1(3)
>=0', 'A1(4)=0', a1, a2, a3, a4);

Try,

[a1, a2, a3, a4] = solve([A1(1) '=1'], A1(2), A1(3), A1(4), a1, a2, a3, a4)
--
"There are some ideas so wrong that only a very intelligent person
could believe in them." -- George Orwell

Re: Solve Array of symbolic functions

Ben Hinkle — Tue, 30 Oct 2007 18:58:32 -0400

"Walter Roberson" <roberson@ibd.nrc-cnrc.gc.ca> wrote in message
news:fg7kpq$2vn$1@canopus.cc.umanitoba.ca...
> In article <fg7h3s$mk1$1@fred.mathworks.com>,
> Quint Segers <q.segers@gmail.com> wrote:
>>if A1 is an array of symbolic funtions:
>>A1=
>> -a1+a2-a3+a4
>> -1/27*a1+1/9*a2-1/3*a3+a4
>> 1/27*a1+1/9*a2+1/3*a3+a4
>> a1+a2+a3+a4
>>
>>Why can't I use solve like:
>>
>>[a1, a2, a3, a4] = solve('A1(1)=1', 'A1(2)=0', 'A1(3)
>>=0', 'A1(4)=0', a1, a2, a3, a4);
>
> Try,
>
> [a1, a2, a3, a4] = solve([A1(1) '=1'], A1(2), A1(3), A1(4), a1, a2, a3,
> a4)

Will that concatenation work? An alternative:

[a1, a2, a3, a4] = solve(A1(1)-1, A1(2), A1(3), A1(4), a1, a2, a3, a4)

Re: Solve Array of symbolic functions

Quint Segers — Wed, 26 Dec 2007 13:16:50 -0500

> [a1, a2, a3, a4] = solve(A1(1)-1, A1(2), A1(3), A1(4),
a1, a2, a3, a4)

Thanks. This one gives me the right result.
Quint