How can i fix 'Unable to solve the collocation equations -- a singular jacobian encountered' problem?

Question

Seymen 2017-5-16

0
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https://ww2.mathworks.cn/matlabcentral/answers/340536-how-can-i-fix-unable-to-solve-the-collocation-equations-a-singular-jacobian-encountered-problem

回答： Torsten 2017-5-17

采纳的回答： Torsten

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Our coupled equations:

f'''+(12/5)*f''*f-(4/5)*((f')^2)+q=0 q''+(12/5)*Pr*(f*q)'=0

Here is our boundary conditions:

q(0)=1 q'(0)=0 q(inf)=0

f''(0)=0 f'(inf)=0 f(0)=0 inf:infinity

Here is our function:

function dydx = fun(x,y)
 Pr=0.1;
 dydx = [ y(2)
 y(3)
 -(12/5)*(y(3))*y(1)+(4/5)*(y(2)^2)-y(4)
 y(5)
 -(12/5)*Pr*(y(4)*y(2)+y(5)*y(1))];
 end % End nested function
And boundary conditions:
 res = fun_bc(f0,finf)
   res = [ f0(1)-1
  f0(2)
  f0(3)
  f0(1)
   finf(2)];

*y(1)=f y(2)=f' y(3)=f'' y(4)=q y(5)=q' However, when we run the code we face the problem 'Unable to solve the collocation equations -- a singular jacobian encountered.' How can we solve this problem?

Thanks