solvefour.m

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;
syms x y t z10 z20 k1 k2 k3  k4;

A12='-(k1-k2)^2/(k1*k2)';
A13='-(k1-k3)^2/(k1*k3)';
A14='-(k1-k4)^2/(k1*k4)';
A23='-(k2-k3)^2/(k2*k3)';
A24='-(k2-k4)^2/(k2*k4)';
A34='-(k3-k4)^2/(k3*k4)';

w1='k1^2/2';
w2='k2^2/2';
w3='k3^2/2';
w4='k4^2/2';

p1='k1^3/4';
p2='k2^3/4';
p3='k3^3/4';
p4='k4^3/4';

z1='k1*x+w1*y+p1*t+z10';
z2='k2*x+w2*y+p2*t+z20';
z3='k3*x+w3*y+p3*t+z30';
z4='k4*x+w4*y+p4*t+z40';

f='1+exp(z1)+exp(z2)+exp(z3)+exp(z4)';
g='exp(z1)+exp(z2)+exp(z3)+exp(z4)+exp(z1+z2+A12)+exp(z1+z3+A13)+exp(z1+z4+A14)+exp(z2+z3+A23)+exp(z2+z4+A24)+exp(z3+z4+A34)';

f=subs(f,'z1','k1*x+w1*y+p1*t+z10');
f=subs(f,'z2','k2*x+w2*y+p2*t+z20');
f=subs(f,'z3','k3*x+w3*y+p3*t+z30');
f=subs(f,'z4','k4*x+w4*y+p4*t+z40');

g=subs(g,'z1','k1*x+w1*y+p1*t+z10');
g=subs(g,'z2','k2*x+w2*y+p2*t+z20');
g=subs(g,'z3','k3*x+w3*y+p3*t+z30');
g=subs(g,'z4','k4*x+w4*y+p4*t+z40');

u=log(g/f);
u=-diff(u,'x')/2;

v=log(g*f);
v=-diff(v,'x',2)/2;

u=subs(u,'k1*x+w1*y+p1*t+z10','z1');
u=subs(u,'k2*x+w2*y+p2*t+z20','z2');
u=subs(u,'k3*x+w3*y+p3*t+z30','z3');
u=subs(u,'k4*x+w4*y+p4*t+z40','z4');

u=simplify(u);

v=subs(v,'k1*x+w1*y+p1*t+z10','z1');
v=subs(v,'k2*x+w2*y+p2*t+z20','z2');
v=subs(v,'k3*x+w3*y+p3*t+z30','z3');
v=subs(v,'k4*x+w4*y+p4*t+z40','z4');

v=simplify(v);