mskalsi

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These are questions asked by mskalsi

Can anybody please tell, where I can find seminar/workshops on Maple training ?

Regards

Dear All

I need to reduce system of differential equation system into triangular system which I came to know can be done using Maple package "DifferentialAlgebra", but I do not know how to use this package for triangularization.

The differential system is DetSys derived from  some PDE:

 

with(PDEtools):

DepVars := [f(u(x, t)), u(x, t)]; 1; declare(f(u(x, t)), u(x, t))

[f(u(x, t)), u(x, t)]

 

f(u(x, t))*`will now be displayed as`*f

 

u(x, t)*`will now be displayed as`*u

(1)

PDE1 := diff(u(x, t), t, t)-(diff(u(x, t), x, x))-f(u) = 0

diff(diff(u(x, t), t), t)-(diff(diff(u(x, t), x), x))-f(u) = 0

(2)

G := [xi(x, t, u), tau(x, t, u), phi(x, t, u)]

[xi(x, t, u), tau(x, t, u), phi(x, t, u)]

(3)

declare(G)

phi(x, t, u)*`will now be displayed as`*phi

 

tau(x, t, u)*`will now be displayed as`*tau

 

xi(x, t, u)*`will now be displayed as`*xi

(4)

DetSys := DeterminingPDE(PDE1, G, integrabilityconditions = false)

{-2*(diff(diff(tau(x, t, u), t), u))+diff(diff(phi(x, t, u), u), u), 2*(diff(diff(tau(x, t, u), u), x))-2*(diff(diff(xi(x, t, u), t), u)), 2*(diff(diff(xi(x, t, u), u), x))-(diff(diff(phi(x, t, u), u), u)), 2*(diff(tau(x, t, u), x))-2*(diff(xi(x, t, u), t)), 2*(diff(xi(x, t, u), x))-2*(diff(tau(x, t, u), t)), diff(diff(tau(x, t, u), x), x)+2*(diff(diff(phi(x, t, u), t), u))-(diff(diff(tau(x, t, u), t), t))-3*(diff(tau(x, t, u), u))*f(u), diff(diff(xi(x, t, u), x), x)-2*(diff(diff(phi(x, t, u), u), x))-(diff(diff(xi(x, t, u), t), t))-f(u)*(diff(xi(x, t, u), u)), -(diff(diff(phi(x, t, u), x), x))+diff(diff(phi(x, t, u), t), t)-phi(x, t, u)*(diff(f(u), u))+(diff(phi(x, t, u), u))*f(u)-2*(diff(tau(x, t, u), t))*f(u), diff(diff(tau(x, t, u), u), u), diff(diff(xi(x, t, u), u), u), diff(tau(x, t, u), u), diff(xi(x, t, u), u)}

(5)

for EQ in sort([op(DetSys)], length) do EQ = 0 end do:

 

 

Download [1117]_Symmetries_determination.mw

Regards

Dear All

In following I tried to find symmetries of certain partial differential equation taken from paper "Group classification and exact solutions of generalized modified Boussinesq equation". But the determining equations are not matching with equations obtained in paper.


with(PDEtools)

DepVars := [f(u(x, t)), u(x, t)]; declare(f(u(x, t)), u(x, t))

[f(u(x, t)), u(x, t)]

 

f(u(x, t))*`will now be displayed as`*f

 

u(x, t)*`will now be displayed as`*u

(1)

PDE1 := diff(u(x, t), t, t)-delta*(diff(u(x, t), x, x, t, t))-(diff(f(u(x, t)), x, x))

diff(diff(u(x, t), t), t)-delta*(diff(diff(diff(diff(u(x, t), t), t), x), x))-((D@@2)(f))(u(x, t))*(diff(u(x, t), x))^2-(D(f))(u(x, t))*(diff(diff(u(x, t), x), x))

(2)

G := [seq(xi[j](x, t, u), j = [x, t]), seq(eta[j](x, t, u), j = [u])]

[xi[x](x, t, u), xi[t](x, t, u), eta[u](x, t, u)]

(3)

declare(G)

eta(x, t, u)*`will now be displayed as`*eta

 

xi(x, t, u)*`will now be displayed as`*xi

(4)

DetSys := DeterminingPDE(PDE1, G, integrabilityconditions = false)

{diff(diff(xi[t](x, t, u), u), u)-(diff(diff(diff(diff(xi[t](x, t, u), u), u), x), x))*delta, (diff(diff(eta[u](x, t, u), x), x))*(diff(f(u), u))+(diff(diff(diff(diff(eta[u](x, t, u), t), t), x), x))*delta-(diff(diff(eta[u](x, t, u), t), t)), -(diff(diff(xi[x](x, t, u), u), u))*(diff(f(u), u))-(diff(diff(diff(diff(xi[x](x, t, u), t), t), u), u))*delta+(diff(diff(f(u), u), u))*(diff(xi[x](x, t, u), u)), 2*(diff(diff(diff(diff(xi[x](x, t, u), u), u), u), x))+2*(diff(diff(diff(diff(xi[t](x, t, u), t), u), u), u))-(diff(diff(diff(diff(eta[u](x, t, u), u), u), u), u)), 2*(diff(diff(diff(xi[x](x, t, u), u), u), x))+2*(diff(diff(diff(xi[t](x, t, u), t), u), u))-(diff(diff(diff(eta[u](x, t, u), u), u), u)), 4*(diff(diff(xi[x](x, t, u), t), x))-2*(diff(diff(eta[u](x, t, u), t), u))+diff(diff(xi[t](x, t, u), t), t), 2*(diff(diff(xi[x](x, t, u), u), x))+2*(diff(diff(xi[t](x, t, u), t), u))-(diff(diff(eta[u](x, t, u), u), u)), diff(diff(xi[x](x, t, u), x), x)-2*(diff(diff(eta[u](x, t, u), u), x))+4*(diff(diff(xi[t](x, t, u), t), x)), -2*(diff(xi[x](x, t, u), x))+(diff(diff(diff(eta[u](x, t, u), u), x), x))*delta-2*(diff(diff(diff(xi[t](x, t, u), t), x), x))*delta, -(diff(diff(diff(xi[x](x, t, u), u), x), x))*delta-4*(diff(diff(diff(xi[t](x, t, u), t), u), x))*delta+2*(diff(diff(diff(eta[u](x, t, u), u), u), x))*delta-2*(diff(xi[x](x, t, u), u)), (diff(diff(f(u), u), u))*eta[u](x, t, u)+(diff(diff(diff(eta[u](x, t, u), t), t), u))*delta-2*(diff(diff(diff(xi[x](x, t, u), t), t), x))*delta+2*(diff(xi[t](x, t, u), t))*(diff(f(u), u)), -2*(diff(xi[t](x, t, u), u))*(diff(f(u), u))+4*delta*(diff(diff(diff(eta[u](x, t, u), t), u), u))-2*(diff(diff(diff(xi[t](x, t, u), t), t), u))*delta-8*(diff(diff(diff(xi[x](x, t, u), t), u), x))*delta, 2*(diff(xi[t](x, t, u), u))*(diff(f(u), u))+2*delta*(diff(diff(diff(eta[u](x, t, u), t), u), u))-(diff(diff(diff(xi[t](x, t, u), t), t), u))*delta-4*(diff(diff(diff(xi[x](x, t, u), t), u), x))*delta, 2*(diff(diff(xi[t](x, t, u), t), u))-(diff(diff(eta[u](x, t, u), u), u))+(diff(diff(diff(diff(eta[u](x, t, u), u), u), x), x))*delta-2*(diff(diff(diff(diff(xi[t](x, t, u), t), u), x), x))*delta, diff(diff(xi[x](x, t, u), u), u)-4*(diff(diff(diff(diff(xi[t](x, t, u), t), u), u), x))*delta+2*(diff(diff(diff(diff(eta[u](x, t, u), u), u), u), x))*delta-(diff(diff(diff(diff(xi[x](x, t, u), u), u), x), x))*delta, 2*(diff(xi[x](x, t, u), u))-8*(diff(diff(diff(xi[t](x, t, u), t), u), x))*delta+4*(diff(diff(diff(eta[u](x, t, u), u), u), x))*delta-2*(diff(diff(diff(xi[x](x, t, u), u), x), x))*delta, -(diff(diff(xi[t](x, t, u), u), u))*(diff(f(u), u))-4*(diff(diff(diff(diff(xi[x](x, t, u), t), u), u), x))*delta-(diff(diff(diff(diff(xi[t](x, t, u), t), t), u), u))*delta+(diff(diff(f(u), u), u))*(diff(xi[t](x, t, u), u))+2*(diff(diff(diff(diff(eta[u](x, t, u), t), u), u), u))*delta, -(diff(diff(xi[t](x, t, u), x), x))*(diff(f(u), u))+diff(diff(xi[t](x, t, u), t), t)-2*(diff(diff(eta[u](x, t, u), t), u))+2*(diff(diff(diff(diff(eta[u](x, t, u), t), u), x), x))*delta-(diff(diff(diff(diff(xi[t](x, t, u), t), t), x), x))*delta, -2*(diff(xi[t](x, t, u), x))*(diff(f(u), u))+2*(diff(xi[x](x, t, u), t))-2*(diff(diff(diff(xi[x](x, t, u), t), x), x))*delta+4*(diff(diff(diff(eta[u](x, t, u), t), u), x))*delta-2*(diff(diff(diff(xi[t](x, t, u), t), t), x))*delta, (diff(diff(diff(diff(eta[u](x, t, u), t), t), u), u))*delta-2*(diff(diff(diff(diff(xi[x](x, t, u), t), t), u), x))*delta+(diff(diff(diff(f(u), u), u), u))*eta[u](x, t, u)+(diff(diff(eta[u](x, t, u), u), u))*(diff(f(u), u))-2*(diff(diff(xi[x](x, t, u), u), x))*(diff(f(u), u))+2*(diff(diff(f(u), u), u))*(diff(xi[t](x, t, u), t)+(1/2)*(diff(eta[u](x, t, u), u))), -(diff(diff(xi[x](x, t, u), x), x))*(diff(f(u), u))+2*(diff(diff(eta[u](x, t, u), u), x))*(diff(f(u), u))+2*(diff(diff(f(u), u), u))*(diff(eta[u](x, t, u), x))+diff(diff(xi[x](x, t, u), t), t)-delta*(diff(diff(diff(diff(xi[x](x, t, u), t), t), x), x))+2*delta*(diff(diff(diff(diff(eta[u](x, t, u), t), t), u), x)), 2*(diff(diff(xi[x](x, t, u), t), u))-2*(diff(diff(xi[t](x, t, u), u), x))*(diff(f(u), u))-2*(diff(xi[t](x, t, u), x))*(diff(diff(f(u), u), u))+4*(diff(diff(diff(diff(eta[u](x, t, u), t), u), u), x))*delta-2*(diff(diff(diff(diff(xi[t](x, t, u), t), t), u), x))*delta-2*(diff(diff(diff(diff(xi[x](x, t, u), t), u), x), x))*delta, diff(diff(diff(diff(xi[t](x, t, u), u), u), u), u), diff(diff(diff(diff(xi[t](x, t, u), u), u), u), x), diff(diff(diff(diff(xi[x](x, t, u), t), u), u), u), diff(diff(diff(diff(xi[x](x, t, u), u), u), u), u), diff(diff(diff(xi[t](x, t, u), u), u), u), diff(diff(diff(xi[t](x, t, u), u), u), x), diff(diff(diff(xi[t](x, t, u), u), x), x), diff(diff(diff(xi[x](x, t, u), t), t), u), diff(diff(diff(xi[x](x, t, u), t), u), u), diff(diff(diff(xi[x](x, t, u), u), u), u), diff(diff(xi[t](x, t, u), u), u), diff(diff(xi[t](x, t, u), u), x), diff(diff(xi[t](x, t, u), x), x), diff(diff(xi[x](x, t, u), t), t), diff(diff(xi[x](x, t, u), t), u), diff(diff(xi[x](x, t, u), u), u), diff(xi[t](x, t, u), u), diff(xi[t](x, t, u), x), diff(xi[x](x, t, u), t), diff(xi[x](x, t, u), u)}

(5)

for EQ in sort([op(DetSys)], length) do EQ = 0 end do

diff(xi[t](x, t, u), u) = 0

 

diff(xi[t](x, t, u), x) = 0

 

diff(xi[x](x, t, u), t) = 0

 

diff(xi[x](x, t, u), u) = 0

 

diff(diff(xi[t](x, t, u), u), u) = 0

 

diff(diff(xi[t](x, t, u), u), x) = 0

 

diff(diff(xi[t](x, t, u), x), x) = 0

 

diff(diff(xi[x](x, t, u), t), t) = 0

 

diff(diff(xi[x](x, t, u), t), u) = 0

 

diff(diff(xi[x](x, t, u), u), u) = 0

 

diff(diff(diff(xi[t](x, t, u), u), u), u) = 0

 

diff(diff(diff(xi[t](x, t, u), u), u), x) = 0

 

diff(diff(diff(xi[t](x, t, u), u), x), x) = 0

 

diff(diff(diff(xi[x](x, t, u), t), t), u) = 0

 

diff(diff(diff(xi[x](x, t, u), t), u), u) = 0

 

diff(diff(diff(xi[x](x, t, u), u), u), u) = 0

 

diff(diff(diff(diff(xi[t](x, t, u), u), u), u), u) = 0

 

diff(diff(diff(diff(xi[t](x, t, u), u), u), u), x) = 0

 

diff(diff(diff(diff(xi[x](x, t, u), t), u), u), u) = 0

 

diff(diff(diff(diff(xi[x](x, t, u), u), u), u), u) = 0

 

diff(diff(xi[t](x, t, u), u), u)-(diff(diff(diff(diff(xi[t](x, t, u), u), u), x), x))*delta = 0

 

4*(diff(diff(xi[x](x, t, u), t), x))-2*(diff(diff(eta[u](x, t, u), t), u))+diff(diff(xi[t](x, t, u), t), t) = 0

 

2*(diff(diff(xi[x](x, t, u), u), x))+2*(diff(diff(xi[t](x, t, u), t), u))-(diff(diff(eta[u](x, t, u), u), u)) = 0

 

diff(diff(xi[x](x, t, u), x), x)-2*(diff(diff(eta[u](x, t, u), u), x))+4*(diff(diff(xi[t](x, t, u), t), x)) = 0

 

2*(diff(diff(diff(xi[x](x, t, u), u), u), x))+2*(diff(diff(diff(xi[t](x, t, u), t), u), u))-(diff(diff(diff(eta[u](x, t, u), u), u), u)) = 0

 

-2*(diff(xi[x](x, t, u), x))+(diff(diff(diff(eta[u](x, t, u), u), x), x))*delta-2*(diff(diff(diff(xi[t](x, t, u), t), x), x))*delta = 0

 

(diff(diff(eta[u](x, t, u), x), x))*(diff(f(u), u))+(diff(diff(diff(diff(eta[u](x, t, u), t), t), x), x))*delta-(diff(diff(eta[u](x, t, u), t), t)) = 0

 

2*(diff(diff(diff(diff(xi[x](x, t, u), u), u), u), x))+2*(diff(diff(diff(diff(xi[t](x, t, u), t), u), u), u))-(diff(diff(diff(diff(eta[u](x, t, u), u), u), u), u)) = 0

 

-(diff(diff(xi[x](x, t, u), u), u))*(diff(f(u), u))-(diff(diff(diff(diff(xi[x](x, t, u), t), t), u), u))*delta+(diff(diff(f(u), u), u))*(diff(xi[x](x, t, u), u)) = 0

 

-(diff(diff(diff(xi[x](x, t, u), u), x), x))*delta-4*(diff(diff(diff(xi[t](x, t, u), t), u), x))*delta+2*(diff(diff(diff(eta[u](x, t, u), u), u), x))*delta-2*(diff(xi[x](x, t, u), u)) = 0

 

2*(diff(xi[x](x, t, u), u))-8*(diff(diff(diff(xi[t](x, t, u), t), u), x))*delta+4*(diff(diff(diff(eta[u](x, t, u), u), u), x))*delta-2*(diff(diff(diff(xi[x](x, t, u), u), x), x))*delta = 0

 

2*(diff(diff(xi[t](x, t, u), t), u))-(diff(diff(eta[u](x, t, u), u), u))+(diff(diff(diff(diff(eta[u](x, t, u), u), u), x), x))*delta-2*(diff(diff(diff(diff(xi[t](x, t, u), t), u), x), x))*delta = 0

 

(diff(diff(f(u), u), u))*eta[u](x, t, u)+(diff(diff(diff(eta[u](x, t, u), t), t), u))*delta-2*(diff(diff(diff(xi[x](x, t, u), t), t), x))*delta+2*(diff(xi[t](x, t, u), t))*(diff(f(u), u)) = 0

 

-2*(diff(xi[t](x, t, u), u))*(diff(f(u), u))+4*delta*(diff(diff(diff(eta[u](x, t, u), t), u), u))-2*(diff(diff(diff(xi[t](x, t, u), t), t), u))*delta-8*(diff(diff(diff(xi[x](x, t, u), t), u), x))*delta = 0

 

2*(diff(xi[t](x, t, u), u))*(diff(f(u), u))+2*delta*(diff(diff(diff(eta[u](x, t, u), t), u), u))-(diff(diff(diff(xi[t](x, t, u), t), t), u))*delta-4*(diff(diff(diff(xi[x](x, t, u), t), u), x))*delta = 0

 

diff(diff(xi[x](x, t, u), u), u)-4*(diff(diff(diff(diff(xi[t](x, t, u), t), u), u), x))*delta+2*(diff(diff(diff(diff(eta[u](x, t, u), u), u), u), x))*delta-(diff(diff(diff(diff(xi[x](x, t, u), u), u), x), x))*delta = 0

 

-2*(diff(xi[t](x, t, u), x))*(diff(f(u), u))+2*(diff(xi[x](x, t, u), t))-2*(diff(diff(diff(xi[x](x, t, u), t), x), x))*delta+4*(diff(diff(diff(eta[u](x, t, u), t), u), x))*delta-2*(diff(diff(diff(xi[t](x, t, u), t), t), x))*delta = 0

 

-(diff(diff(xi[t](x, t, u), x), x))*(diff(f(u), u))+diff(diff(xi[t](x, t, u), t), t)-2*(diff(diff(eta[u](x, t, u), t), u))+2*(diff(diff(diff(diff(eta[u](x, t, u), t), u), x), x))*delta-(diff(diff(diff(diff(xi[t](x, t, u), t), t), x), x))*delta = 0

 

-(diff(diff(xi[t](x, t, u), u), u))*(diff(f(u), u))-4*(diff(diff(diff(diff(xi[x](x, t, u), t), u), u), x))*delta-(diff(diff(diff(diff(xi[t](x, t, u), t), t), u), u))*delta+(diff(diff(f(u), u), u))*(diff(xi[t](x, t, u), u))+2*(diff(diff(diff(diff(eta[u](x, t, u), t), u), u), u))*delta = 0

 

-(diff(diff(xi[x](x, t, u), x), x))*(diff(f(u), u))+2*(diff(diff(eta[u](x, t, u), u), x))*(diff(f(u), u))+2*(diff(diff(f(u), u), u))*(diff(eta[u](x, t, u), x))+diff(diff(xi[x](x, t, u), t), t)-delta*(diff(diff(diff(diff(xi[x](x, t, u), t), t), x), x))+2*delta*(diff(diff(diff(diff(eta[u](x, t, u), t), t), u), x)) = 0

 

2*(diff(diff(xi[x](x, t, u), t), u))-2*(diff(diff(xi[t](x, t, u), u), x))*(diff(f(u), u))-2*(diff(xi[t](x, t, u), x))*(diff(diff(f(u), u), u))+4*(diff(diff(diff(diff(eta[u](x, t, u), t), u), u), x))*delta-2*(diff(diff(diff(diff(xi[t](x, t, u), t), t), u), x))*delta-2*(diff(diff(diff(diff(xi[x](x, t, u), t), u), x), x))*delta = 0

 

(diff(diff(diff(diff(eta[u](x, t, u), t), t), u), u))*delta-2*(diff(diff(diff(diff(xi[x](x, t, u), t), t), u), x))*delta+(diff(diff(diff(f(u), u), u), u))*eta[u](x, t, u)+(diff(diff(eta[u](x, t, u), u), u))*(diff(f(u), u))-2*(diff(diff(xi[x](x, t, u), u), x))*(diff(f(u), u))+2*(diff(diff(f(u), u), u))*(diff(xi[t](x, t, u), t)+(1/2)*(diff(eta[u](x, t, u), u))) = 0

(6)

DetSys1 := dsubs(diff(xi[t](x, t, u), u) = 0, diff(xi[t](x, t, u), x) = 0, diff(xi[x](x, t, u), t) = 0, diff(xi[x](x, t, u), u) = 0, diff(eta[u](x, t, u), u, u) = 0, diff(eta[u](x, t, u), x, u, t) = 0, DetSys)

{0, diff(diff(xi[t](x, t, u), t), t)-2*(diff(diff(eta[u](x, t, u), t), u)), diff(diff(xi[x](x, t, u), x), x)-2*(diff(diff(eta[u](x, t, u), u), x)), -2*(diff(xi[x](x, t, u), x))+(diff(diff(diff(eta[u](x, t, u), u), x), x))*delta, (diff(diff(diff(f(u), u), u), u))*eta[u](x, t, u)+2*(diff(diff(f(u), u), u))*(diff(xi[t](x, t, u), t))+(diff(diff(f(u), u), u))*(diff(eta[u](x, t, u), u)), (diff(diff(f(u), u), u))*eta[u](x, t, u)+(diff(diff(diff(eta[u](x, t, u), t), t), u))*delta+2*(diff(xi[t](x, t, u), t))*(diff(f(u), u)), (diff(diff(eta[u](x, t, u), x), x))*(diff(f(u), u))+(diff(diff(diff(diff(eta[u](x, t, u), t), t), x), x))*delta-(diff(diff(eta[u](x, t, u), t), t)), -(diff(diff(xi[x](x, t, u), x), x))*(diff(f(u), u))+2*(diff(diff(eta[u](x, t, u), u), x))*(diff(f(u), u))+2*(diff(diff(f(u), u), u))*(diff(eta[u](x, t, u), x))}

(7)

for EQ in sort([op(DetSys1)], length) do EQ = 0 end do

0 = 0

 

diff(diff(xi[t](x, t, u), t), t)-2*(diff(diff(eta[u](x, t, u), t), u)) = 0

 

diff(diff(xi[x](x, t, u), x), x)-2*(diff(diff(eta[u](x, t, u), u), x)) = 0

 

-2*(diff(xi[x](x, t, u), x))+(diff(diff(diff(eta[u](x, t, u), u), x), x))*delta = 0

 

(diff(diff(f(u), u), u))*eta[u](x, t, u)+(diff(diff(diff(eta[u](x, t, u), t), t), u))*delta+2*(diff(xi[t](x, t, u), t))*(diff(f(u), u)) = 0

 

(diff(diff(eta[u](x, t, u), x), x))*(diff(f(u), u))+(diff(diff(diff(diff(eta[u](x, t, u), t), t), x), x))*delta-(diff(diff(eta[u](x, t, u), t), t)) = 0

 

(diff(diff(diff(f(u), u), u), u))*eta[u](x, t, u)+2*(diff(diff(f(u), u), u))*(diff(xi[t](x, t, u), t))+(diff(diff(f(u), u), u))*(diff(eta[u](x, t, u), u)) = 0

 

-(diff(diff(xi[x](x, t, u), x), x))*(diff(f(u), u))+2*(diff(diff(eta[u](x, t, u), u), x))*(diff(f(u), u))+2*(diff(diff(f(u), u), u))*(diff(eta[u](x, t, u), x)) = 0

(8)

The third equation in (8) can simplify last equation. This will give us eta[u][x] = 0as f[u, u] is non zero.

NULL


Download [1116]_Symmetries_Determination.mw[1116]_Group_classification_and_exact_solutions_of_generalized_modified_Boussinesq_equation.pdf

Regards


Suppose I have a PDE

i*psi[t]+psi[xx] = epsilon*(abs(psi)^2)[yy]*psi:

Here I can set psi = u(x, y, t)+i*v(x, y, t), i = sqrt(-1)

Then my query is, how can I obtain simplified resultant system after equating real and imaginary parts. Of course there would be two partial differential equations in u(x, y, t)and v(x, y, t) and those can also be written down manually very easily but this process becomes difficult when we have large system.

Please help !!!


Download Maple_Query_1.mw

Regards

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