How to order with respect to functions AND derivatives

Posted on 2008-04-24 10:46 By sasomao (

23)

Categories:

How do I ...? with Maple

Good mornig,

I've this expression

diff(Q(theta, `ϕ`), `ϕ`, `ϕ`)+diff(S(theta, `ϕ`), `ϕ`, `ϕ`)+(diff(S(theta, `ϕ`), theta)+diff(Q(theta, `ϕ`), theta))*cos(theta)*sin(theta)+(4*M*G*k*(diff(Q(theta, `ϕ`), theta, theta))-4*M*G*k*S(theta, `ϕ`)+4*M*G*k*Q(theta, `ϕ`)-4*M*G*k*(diff(S(theta, `ϕ`), theta, theta))-(diff(S(theta, `ϕ`), theta, theta))-(diff(Q(theta, `ϕ`), theta, theta)))*sin(theta)^2

And I would order the factors in order to have all the factors with S(theta,phi) after (or before) ALL the factors with Q(theta,phi).

I've tried with sort(..., Q(theta,phi)) but this seems not work on the derivative like diff(Q(...),theta)

So, there is a metod to obtein this ordering? Or (better) to print this expression like two differential operator acting on S and Q?

Thank you

Sorry for the code, I

Comment on 2008-04-24 10:51 from sasomao (

23)

Sorry for the code, I don't know what happened. Here there is the more readable version:

Good mornig, I've this expression:

and I would order the factors in order to have all the factors with S(theta,phi) after (or before) ALL the factors with Q(theta,phi). I've tried with sort(..., Q(theta,phi)) but this seems not work on the derivative like diff(Q(...),theta) So, there is a metod to obtein this ordering? Or (better) to print this expression like two differential operator acting on S and Q? Thank you S.

a trick

Comment on 2008-04-24 15:57 from jakubi ( Maple Rating 4

943)

that you may use just for display purposes:

diff(Q(theta, `&varphi;`), `&varphi;`, `&varphi;`)
+diff(S(theta, `&varphi;`), `&varphi;`, `&varphi;`)
+(diff(S(theta, `&varphi;`), theta)+diff(Q(theta, `&varphi;`), theta))
*cos(theta)*sin(theta)+(4*M*G*k*(diff(Q(theta, `&varphi;`), theta, theta))
-4*M*G*k*S(theta, `&varphi;`)+4*M*G*k*Q(theta, `&varphi;`)
-4*M*G*k*(diff(S(theta, `&varphi;`), theta, theta))
-(diff(S(theta, `&varphi;`), theta, theta))
-(diff(Q(theta, `&varphi;`), theta, theta)))*sin(theta)^2;
B:=expand(%);
BQ:=select(has,B,Q):
BS:=select(has,B,S):
subs(Q=`Q `,BQ)+subs(S=`S `,BS);

and operator form

Comment on 2008-04-24 18:30 from jakubi ( Maple Rating 4

943)

DepVars := [Q(theta, `&varphi;`),S(theta, `&varphi;`)];
BJ:= PDEtools:-ToJet(B, DepVars);
select(has,BJ,Q):
DQ:=subs(Q=D,D[]=1,%);
select(has,BJ,S):
DS:=subs(S=D,D[]=1,%);
DS*S+DQ*Q;

(D[2, 2]+cos(theta)*sin(theta)*D[1]-4*sin(theta)^2*M*G*k
-4*sin(theta)^2*M*G*k*D[1, 1]-sin(theta)^2*D[1, 1])*S
+(D[2, 2]+cos(theta)*sin(theta)*D[1]+4*sin(theta)^2*M*G*k*D[1, 1]
+4*sin(theta)^2*M*G*k-sin(theta)^2*D[1, 1])*Q;

I see the html tags in my

Comment on 2008-04-24 10:52 from sasomao (

23)

I see the html tags in my posts after I post it, and I don't know why...

Plain text input format

Comment on 2008-04-24 14:19 from Will ( Maple Rating 4

824)

The problem was that you set your input format to "Plain Text" this causes everything that you type to appear in your post including the HTML tags.

The WYSYWIG editor automatically inserts tags for you, so you shouldn't need to use the plain text input format. I've set your post to the right format.

____
William Spaetzel
MaplePrimes Administrator
Software Developer, Maplesoft

Hi perphs ...

Comment on 2008-04-24 17:30 from federiclet (not verified) (0)

Ciao, I try using factor simply selecting your expression, and things came in order first Q then S.

I do know if the command alterate the original formula, since I'm not a Maple expert.

I'm not sure either this will answer your question since you are talking about operators (that I assumed be Qand S, but as said I might be wrong)

Nevetheless it's worted to at list propose it...

take care

Thankyou

Comment on 2008-04-25 14:14 from sasomao (

23)

Thanks everybody, expecially to Jakubi, for the tricks, it works perfectly!