"Fotis Dimitrakopoulos" <f.dimitrak@gmail.com> wrote in message <kh4ltv$8ub$1@newscl01ah.mathworks.com>...
> Hello every one, I am trying to numerically solve a system of 5 coupled diff. equations using ode15s (i have also tried using different functions), but I get the following warning:
>
> "Warning: Failure at t=2.289553e-01. Unable to meet integration tolerances without reducing the step
> size below the smallest value allowed (4.440892e-16) at time t. ?
>
> Could anyone have an idea about what could I do to get a result? My code is the following:
>
> %define functions
> classdef beta
>
> methods(Static)
> function y = g1(gp, gs, g, yt)
> y = 41*gp^3/(96*pi^2) + (1/16*pi^2)^2*((44/3)*gs^2*gp^3 + (9/2*g^2 + (199/18)*gp^2 - (17/6)*yt^2)*gp^3);
> end
> function y = g2(gp, gs, g, yt)
> y = -19*g^3/(96*pi^2) + (1/16*pi^2)^2*(12*gs^2*g^3+((35/6)*g^2 + (3/2)*gp^2 - (3/2)*yt^2)*g^3);
> end
> function y = g3(gp, gs, g, yt)
> y = -7*gs^3/(16*pi^2) + (1/16*pi^2)^2*gs^3*((9/2)*g^2 - 26*gs^2 + (11/6)*gp^2 - 2*yt^2);
> end
> function y = gamma(g, gp, gs, yt, lam)
> y = (-9*g^2 - 3*gp^2 + 12*yt^2)/(64*pi^2) + ((1/(16*pi^2))^2)*((1/6)*lam^2 ...
> - (27/4)*yt^4 + 20*gs^2*yt^2 + (45/8)*g^2*yt^2 + (85/24)*gp^2*yt^2 - (271/32)*g^4 + (9/16)*g^2*gp^2 + (431/96)*gp^4);
> end
> function y = bf(yt, g, gp)
> y = 3/16*(3*g^4 + 2*g^2*gp^2 + gp^4) - 3*yt^4;
> end
> function y = blam(yt, g, gp, gs, lam)
> y = 4*lam*beta.gamma(g, gp, gs, yt, lam) + (12*lam^2 + beta.bf(yt, g, gp))/(8*pi^2) + (1/(16*pi^2))^2*(80*gs^2*yt^2*lam - 192*gs^2*yt^4 + (915/8)*g^6 - (289/8)*gp^2*g^4 - (27/2)*yt^2*g^4 - (73/8)*lam*g^4 - (559/8)*gp^4*g^2 + 63*gp^2*yt^2*g^2 + (39/4)*gp^2*lam*g^2 - 3*yt^4*lam + (45/2)*yt^2*lam*g^2 - (379/8)*gp^6 + 180*yt^6 - 16*gp^2*yt^4 - (26/3)*lam^3 - (57/2)*gp^4*yt^2 - 24*yt^2*lam^2 + 6*(3*g^2 + gp^2)*lam^2 + (629/24)*gp^4*lam + (85/6)*gp^2*yt^2*lam);
> end
> function y = yuk(yt, g, gp, gs, lam)
> y = yt*(9/2* yt^2 - 9*g^2/4 - 17/12*gp^2 - 8*gs^2)/(16*pi^2) + ((1/16*pi^2)^2)*yt*(-108*gs^4 + 9*g^2*gs^2 + (19/9)*gp^2*gs^2 + 36*yt^2*gs^2 - (3/4)*gp^2*g^2 - (23/4)*g^4 + (1187/216)*gp^4 - ...
> 12*yt^4 + (1/6)*lam^2 + yt^2*((225/16)*g^2 + (131/16)*gp^2 - 2*lam));
> end
> end
> end
>
>
> %system to solve
> function dy = system(t,y)
>
> dy = zeros(5,1);
> dy(1)=beta.g1(y(1),y(3),y(2),y(4));
> dy(2)=beta.g2(y(1),y(3),y(2),y(4));
> dy(3)=beta.g3(y(1),y(3),y(2),y(4));
> dy(4)=beta.yuk(y(4),y(2),y(1),y(3),y(5));
> dy(5)=beta.blam(y(4),y(2),y(1),y(3),y(5));
> end
>
> and then I give the command:
>
> [T,Y] = ode15s(@system,[0. 12],[0.357452 0.65171 1.1645 0.967834 0.139429]);
>
> P.S: This is my first post/question, so I apologize for any inconvenience.
>
> Thanks a lot
I sent the code to the email adress you provided in the forum.
Best wishes
Torsten.![]()
> Hello every one, I am trying to numerically solve a system of 5 coupled diff. equations using ode15s (i have also tried using different functions), but I get the following warning:
>
> "Warning: Failure at t=2.289553e-01. Unable to meet integration tolerances without reducing the step
> size below the smallest value allowed (4.440892e-16) at time t. ?
>
> Could anyone have an idea about what could I do to get a result? My code is the following:
>
> %define functions
> classdef beta
>
> methods(Static)
> function y = g1(gp, gs, g, yt)
> y = 41*gp^3/(96*pi^2) + (1/16*pi^2)^2*((44/3)*gs^2*gp^3 + (9/2*g^2 + (199/18)*gp^2 - (17/6)*yt^2)*gp^3);
> end
> function y = g2(gp, gs, g, yt)
> y = -19*g^3/(96*pi^2) + (1/16*pi^2)^2*(12*gs^2*g^3+((35/6)*g^2 + (3/2)*gp^2 - (3/2)*yt^2)*g^3);
> end
> function y = g3(gp, gs, g, yt)
> y = -7*gs^3/(16*pi^2) + (1/16*pi^2)^2*gs^3*((9/2)*g^2 - 26*gs^2 + (11/6)*gp^2 - 2*yt^2);
> end
> function y = gamma(g, gp, gs, yt, lam)
> y = (-9*g^2 - 3*gp^2 + 12*yt^2)/(64*pi^2) + ((1/(16*pi^2))^2)*((1/6)*lam^2 ...
> - (27/4)*yt^4 + 20*gs^2*yt^2 + (45/8)*g^2*yt^2 + (85/24)*gp^2*yt^2 - (271/32)*g^4 + (9/16)*g^2*gp^2 + (431/96)*gp^4);
> end
> function y = bf(yt, g, gp)
> y = 3/16*(3*g^4 + 2*g^2*gp^2 + gp^4) - 3*yt^4;
> end
> function y = blam(yt, g, gp, gs, lam)
> y = 4*lam*beta.gamma(g, gp, gs, yt, lam) + (12*lam^2 + beta.bf(yt, g, gp))/(8*pi^2) + (1/(16*pi^2))^2*(80*gs^2*yt^2*lam - 192*gs^2*yt^4 + (915/8)*g^6 - (289/8)*gp^2*g^4 - (27/2)*yt^2*g^4 - (73/8)*lam*g^4 - (559/8)*gp^4*g^2 + 63*gp^2*yt^2*g^2 + (39/4)*gp^2*lam*g^2 - 3*yt^4*lam + (45/2)*yt^2*lam*g^2 - (379/8)*gp^6 + 180*yt^6 - 16*gp^2*yt^4 - (26/3)*lam^3 - (57/2)*gp^4*yt^2 - 24*yt^2*lam^2 + 6*(3*g^2 + gp^2)*lam^2 + (629/24)*gp^4*lam + (85/6)*gp^2*yt^2*lam);
> end
> function y = yuk(yt, g, gp, gs, lam)
> y = yt*(9/2* yt^2 - 9*g^2/4 - 17/12*gp^2 - 8*gs^2)/(16*pi^2) + ((1/16*pi^2)^2)*yt*(-108*gs^4 + 9*g^2*gs^2 + (19/9)*gp^2*gs^2 + 36*yt^2*gs^2 - (3/4)*gp^2*g^2 - (23/4)*g^4 + (1187/216)*gp^4 - ...
> 12*yt^4 + (1/6)*lam^2 + yt^2*((225/16)*g^2 + (131/16)*gp^2 - 2*lam));
> end
> end
> end
>
>
> %system to solve
> function dy = system(t,y)
>
> dy = zeros(5,1);
> dy(1)=beta.g1(y(1),y(3),y(2),y(4));
> dy(2)=beta.g2(y(1),y(3),y(2),y(4));
> dy(3)=beta.g3(y(1),y(3),y(2),y(4));
> dy(4)=beta.yuk(y(4),y(2),y(1),y(3),y(5));
> dy(5)=beta.blam(y(4),y(2),y(1),y(3),y(5));
> end
>
> and then I give the command:
>
> [T,Y] = ode15s(@system,[0. 12],[0.357452 0.65171 1.1645 0.967834 0.139429]);
>
> P.S: This is my first post/question, so I apologize for any inconvenience.
>
> Thanks a lot
I sent the code to the email adress you provided in the forum.
Best wishes
Torsten.