Re: Maple question
Nicola Sottocornola wrote:
I wrote this simple prg to compute the Poisson parenthesis of a
mechanical problem in coord. (L1,L2,L3,y1,y2,y3):
------------------------------------------------------------------------
Ps:=proc(f,g)
local P, Poisson;
P:=<<0 | L3 | -L2 | 0 | y3 | -y2>,
<-L3 | 0 | L1 | -y3 | 0 | y1 >,
<L2 | -L1 | 0 | y2 | -y1 | 0>,
<0 | y3 | -y2 | 0 | 0 | 0>,
<-y3 | 0 | y1 | 0 | 0 | 0>,
<y2| -y1 | 0 | 0 | 0 | 0>>;
Poisson:=simplify(evalm([diff(f,L1),diff(f,L2),diff(f,L3),diff(f,y1),diff(f,y2),diff(f,y3)]&*P&*[diff(g,L1),diff(g,L2),diff(g,L3),diff(g,y1),diff(g,y2),diff(g,y3)]));
print(Poisson);
end;
-------------------------------------------------------------------------
If
I ask
Ps(f3,h1);
I obtain the Poisson parenthesis of the functions f3 and h1. Good!
Now, if I write
Ps(f3,h1)-Ps(f1,h2);
Maple does not compute the difference. Why?
I also tried with
eval(Ps(f3,h1)-Ps(f1,h2));
Nothing. Where is the problem?
Post your question at the comp.soft-sys.math.maple newsgroup.
Best regards,
Jose Carlos Santos
.
