How do I extract a particular value in a 'bvp4c' code solver?

Question

naygarp 2018-4-22

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/396615-how-do-i-extract-a-particular-value-in-a-bvp4c-code-solver

评论： naygarp 2018-4-26

I have this bvp4c code for the following equations :

f"=g(g^2+gamma^2)/(g^2+lambda*gamma^2) ------ (1)
g'= (1/3)*f'^2-(2/3)*(f*f")+ Mn*f' ------------------------(2)
t"+Rd*t"+ 2*Pr*f*t'/3+ Nb*t'*p'+Nt*(t')^2= 0------(3)
p"+(2*Lew*f*p')/3+ Nt*t"/Nb= 0 ------------------------(4)

With boundary conditions:

    f=0, f'=1, t=1, p=1; at η=0
  f'=0, t=0, p=0; at η-->infinity

I have used bvp4c solver to solve it numerically

    function sol= proj
clc;clf;clear;
global lambda gama Pr Rd Lew Nb Nt Mn m
%Nb=0.5;
gama=1;  
Mn=1;
Rd=0.1;
Pr=1;
Nb=0.3;
Lew=10;
%lambda=1.5;
pp=0.5;
qq=[0.05:0.01:0.5];
%figure(1)
%plot(2,1);hold on
options=bvpset('stats','on','RelTol',1e-9);
m=linspace(0,10);
solinit= bvpinit(m,[1,0,0,0,0,0,0]);
for i=1:numel(pp)
    lambda=pp(i);
    for i=1:numel(qq);
        Nt=qq(i)
sol= bvp4c(@projfun,@projbc,solinit,options);
y1=deval(sol,0)
%y2=deval(y(6,:),0)
solinit= sol;
plot(sol.x,sol.y(6,:),'LineWidth',2);hold on
%legend('N_{b} = 0.1','N_{b} = 0.3','N_{b} = 0.5');
end
end
end
function f= projfun(x,y)
global lambda gama Pr Rd Lew Nb Nt Mn
f= [y(2)
    y(3)*(y(3)^2+gama^2)/(y(3)^2+lambda*gama^2)
    y(2)^2/3-(2*y(1)*y(3)*(y(3)^2+gama^2))/(3*(y(3)^2+lambda*gama^2))+Mn*y(2)
    y(5)
    -(2*Pr*y(1)*y(5))/(3*(1+Rd)) - (Nb*y(5)*y(7))/(1+Rd) - (Nt*y(5)^2)/(1+Rd)
    y(7)
    -((2*Lew*y(1)*y(7))/3)+ (Nt/Nb)*((2*Pr*y(1)*y(5))/(3*(1+Rd)) + (Nb*y(5)*y(7))/(1+Rd) + (Nt*y(5)^2)/(1+Rd))];
end
function res= projbc(ya,yb)
res= [ya(1); ya(2)-1; ya(4)-1.0; ya(6)-1.0; yb(2); yb(4); yb(6)];
end

I want to extract the values of y(6,:) particularly

Using 'deval(sol,0)' gives all the values of the 'y' rows

Is there any command to extract the values of y(6,:) or y(4,:) in particular.

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Answer 1

MINATI 2018-4-25

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/396615-how-do-i-extract-a-particular-value-in-a-bvp4c-code-solver#answer_317019

Try with this f0 = deval(sol,0); f0(4,:)

Best Wishes

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naygarp 2018-4-26

在 MATLAB Online 中打开

 Thanks, Pradyumna.
Could you please check, whether the above bvp4c code is correctly written, I mean the ODEfunction and the result obtained is correct.

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