doubleu.asv

这是我和同事门一起努力编的的孤立子程序。基本上所以孤立子的情况都考虑到了

clear all;
clc;

deltat=10.0;
ST=-100.0; 	%开始时间
ET=100.0;	%终止时间

SX=-100.0;	%x开始
EX=100.0;	%x终止
x=SX:2:EX;	%x序列

y=x;	%y序列,和x相同
[X,Y]=meshgrid(x,y);

lambda1=3;
r1=1;
alpha1=-sqrt(0.25*lambda1*lambda1-1);
beta1=-4*(2+lambda1*lambda1);

lambda2=4;
r2=2;
alpha2=-sqrt(0.25*lambda2*lambda2-1);
beta2=-4*(2+lambda2*lambda2);

lambda3=5;
r3=2;
alpha3=-sqrt(0.25*lambda3*lambda3-1);
beta3=-4*(2+lambda3*lambda3);

xi1=-alpha1*(X+beta1*ST);
deltapt1=-alpha1*beta1*deltat;

xi2=-alpha2*(X+beta2*ST);
deltapt2=-alpha2*beta2*deltat;

xi3=-alpha3*(X+beta3*ST);
deltapt3=-alpha3*beta3*deltat;


for t=ST:deltat:ET
    sigma1=alpha1*(tanh(xi1)-r1)./(1-r1*tanh(xi1))+0.5*lambda1;
    sigma2=alpha2*(tanh(xi2)-r2)./(1-r2*tanh(xi2))+0.5*lambda2;    
    sigma3=alpha3*(tanh(xi3)-r3)./(1-r3*tanh(xi3))+0.5*lambda3;
    
    Delta=zeros(size(X));
    for j=1:size(X,1)
        temp=[1 sigma1(j,1) lambda1*sigma1(j,1);1 sigma2(j,1) lambda2*sigma2(j,1);1 sigma3(j,1) lambda3*sigma3(j,1)];
        Delta(j,:)=det(temp);
    end

    DeltaC=zeros(size(X));
    for j=1:size(X,1)
        temp=[-lambda1 sigma1(j,1) lambda1*sigma1(j,1);-lambda2 sigma2(j,1) lambda2*sigma2(j,1);-lambda3 sigma3(j,1) lambda3*sigma3(j,1)];
        DeltaC(j,:)=det(temp);
    end
    
    DeltaD=zeros(size(X));
    for j=1:size(X,1)
        temp=[1 sigma1(j,1) -lambda1;1 sigma2(j,1) -lambda2;1 sigma3(j,1) -lambda3];
        DeltaD(j,:)=det(temp);
    end

    
    DeltaA=zeros(size(X));
    for j=1:size(X,1)
        temp=[1 sigma1(j,1) -lambda1*lambda1;1 sigma2(j,1) -lambda2*lambda2;1 sigma3(j,1) -lambda3*lambda3];
        DeltaA(j,:)=det(temp);
    end
    
    DeltaC=DeltaC./Delta;
    DeltaA=DeltaA./DeltaD;
    DeltaD=DeltaD./Delta;
    
    u=DeltaC+DeltaD+DeltaA;
    
    surf(X,Y,u);
    
    pause(0.5);
    
    xi1=xi1+deltapt1;
    xi2=xi2+deltapt2;
    xi3=xi3+deltapt3;
end