# Error in Bvp4c

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Priya M am 23 Okt. 2021
Beantwortet: MOSLI KARIM am 27 Nov. 2023
I'm trying to run the following bvp4c MATLAB code, but keep running into an error:
please anyone find out my mistakes and correct me..
Thank you.
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### Akzeptierte Antwort

Jan am 23 Okt. 2021
You define the variable beta on top of the code, but this does not mean, that it is known in all subfunctions. Pr, gamma and lam are not known inside also.
Either define the constants, where they are needed, or provide them using an anonymous function:
for gamma=0.0:0.25:1
sol = bvpinit(linspace(0,5,50),[0 0 0 0 0 0 0]);
fcn = @(t,y) bvpexam1(t, y, beta, gamma, lam, Pr);
sol1 = bvp4c(fcn, @bcexam1,sol);
...
end
function ysol = bvpexam1(t, y, beta, gamma, lam, Pr)
...
end
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Jan am 27 Okt. 2021
Bearbeitet: Jan am 27 Okt. 2021
f =@(x,y)[y(2);
...
(1/(1+E*y(6)-Pr*gamma*y(1)^2))*(-E*y(7)^2-Pr*y(1)*y(7)+Pr*gamma*y(1)*y(2)*y(7))];
% ^
There is a missing closing square bracket in your code. After adding it I get a result.
Priya M am 28 Okt. 2021
Thanx a lot sir....

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### Weitere Antworten (1)

MOSLI KARIM am 27 Nov. 2023
this code works function d
Pr=0.72;
beta=0.5;
lam=0.2;
E=0.5;
for gamma=0.0:0.25:1
sol = bvpinit(linspace(0,5,50),[0 0 0 0 0 0 0]);
sol1 = bvp4c(@bvpexam1, @bcexam1,sol);
x1 = sol1.x;
y1 = sol1.y;
figure (1)
plot(x1, y1(2,:));
hold on
figure (2)
plot(x1, y1(6,:));
hold on
z = y1(3,1);
p = y1(7,1)'
figure(3)
plot(gamma,y1(7,1),'-bo')
hold on
end
function res = bcexam1(y0, yinf)
res=[y0(1)-0;y0(2)-1;y0(4)-0;y0(6)-1;yinf(2)-0;yinf(4)-0;yinf(6)-0];
end
function ysol = bvpexam1(~,y)
yy1 = (1/(1-beta*y(1)^2))*(-y(1)*y(3)+y(2)^2-2*lam*(y(4)-beta*y(1)*y(5))-2*beta*y(1)*y(2)*y(3));
yy2 = (1/(1-beta*y(1)^2))*(-y(1)*y(5)+y(2)*y(4)+2*lam*(y(2)+beta*(y(2)^2-y(1)*y(3)+y(4)))-2*beta*y(1)*y(2)*y(5));
yy3 = (1/(1+E*y(6)-Pr*gamma*y(1)^2))*(-E*y(7)^2-Pr*y(1)*y(7)+Pr*gamma*y(1)*y(2)*y(7));
ysol = [y(2);y(3);yy1;y(5);yy2;y(7);yy3];
end
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