bvp4c: a singular Jacobian encountered
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Hi everybody! I'm trying to solve the following second order differential equation with known boundary conditions:
global a0 a1 a2 a3 a4 h k JA JB
% J/m^2 -> N/m
a0 = 2.0377638272727268;
a1 = -7.105521894545453;
a2 = 9.234000147272726;
a3 = -5.302489919999999;
a4 = 1.1362478399999998;
k = 5.92*10^-3; % N/m
h = 45.5 *10^-10; % Angstrom -> m
JA = 1.025;
JB = 1.308;
XA = 0;
XB = 45;
meshX = linspace(0,45,100);
Y0 = [JA, JB]; %guess values
init = bvpinit(meshX,Y0);
sol = bvp4c(@myode,@mybc,init);
==============
function yprime = myode(x,y)
global a1 a2 a3 a4 h k
H = h^2/12;
B = a1 + 2*a2.*y(1) + 3*a3.*y(1).^2 + 4*a4.*y(1).^3;
C = 5*a1 + 8*a2.*y(1) + 9*a3.*y(1).^2 + 8*a4.*y(1).^3;
yprime = [y(2);
(C.* y(2).^2)./(B.*y(1)) + (y(1).^5)./H - (k.*y(1).^5)./(H.*B)];
================
function res = mybc(ya,yb)
global JA JB
res = [ya(1) - JA
yb(1) - JB];
The function J(x) assumes the values JA and JB at the extremes of the interval. As reported in the title, I get the following error:
"Error using bvp4c (line 252) Unable to solve the collocation equations -- a singular Jacobian encountered.
Error in mybvp (line 54) sol = bvp4c(@myode,@mybc,init);"
How can I overtake this problem? Thanks in advance for your help. Pinco
4 commentaires
Kiran Pathapati
le 3 Août 2016
@Pinco,
I'm also facing the same errors that you have mentioned in your earlier message. "Error using bvp4c (line 252) Unable to solve the collocation equations -- a singular Jacobian encountered.
Error in mybvp (line 54) sol = bvp4c(@myode,@mybc,init);"
You have mentioned that you were able to fix the errors. Could you please help me fixing the issue.
Thanks, Kiran
Réponses (1)
Sri Mukessh Subramanian
le 21 Août 2015
the boundary condition vector should be specified column wise NOT ROW wise
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