Bvp4c Error, Unable to solve the collocation equations -- a singular Jacobian encountered

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VIJAYKUMAR PATEL 2021-8-13

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/897927-bvp4c-error-unable-to-solve-the-collocation-equations-a-singular-jacobian-encountered

评论： darova 2021-8-14

function sol= proj
global  beta M R Pr m Q Sc Kr la
beta = 2; M = 6.0; R = 1; Pr = 0.75; m = 2.0; Q = 2; Sc = 0.6;
Kr = 0.2;
xa=0; xb=6;
xint=linspace(xa,xb,50);
nxint = length(xint);
LL=[0:0.5:2];
nLL = length(LL);
S = zeros(nLL, nxint);
%figure(1)
%subplot(2,1,1);
%subplot(2,1,2);
solinit= bvpinit([0:10:1000],[0,0,0,0,0,0,0,0]);
for i=1:nLL
    la = LL(i);
    sol= bvp4c(@projfun,@projbc,solinit);
solinit= sol;
 sxint = deval(sol,xint);
        S(i,1) = sxint(3,1);
%plot(sol.x,sol.y(2,:));hold on
end
  figure(1)
    plot(LL, S, '-', 'Linewidth', 1.5); 
    xlabel('\bf \lambda');
    ylabel('\bf C_{f}');
end
function f= projfun(x,y)
global beta M R Pr m Q Sc Kr la
f= [y(2);y(3);y(4);(1/y(1))*y(3)^2-((1+la)/beta)*(M*y(2)+y(2)^2-y(1)*y(3));y(6);(3*Pr/(3+4*R))*(M*y(2)*y(6)-Q*y(5)-y(1)*y(6));y(8);Sc*(m*y(2)*y(7)+Kr*y(7)-y(1)*y(8))];
end
function res= projbc(ya,yb) 
res= [ya(1); ya(2)-1;yb(2);yb(3);ya(5)-1;yb(5);ya(7)-1;yb(7)];
end
%% Error using bvp4c (line 248)
Unable to solve the collocation equations -- a singular Jacobian encountered.
%% Error in vkp (line 18)
    sol= bvp4c(@projfun,@projbc,solinit);