Filter löschen
Filter löschen

Can I obtain results with more significant figures after the decimal place while using 'deval' in a bvp4c solver?

2 Ansichten (letzte 30 Tage)
When I use deval in the bvp4c solver, I get only up to four digits after the decimal place.
Can't I get up to more than four decimal place like five to six decimal place?
What modifications would be needed then?
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=10;
Nb=0.3;
Lew=10;
%lambda=1.5;
pp=0.5;
qq=0.3;
%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)
%f0 = deval(sol,0); f0(5,:)
%y2=deval(y(6,:),0)
solinit= sol;
plot(sol.x,sol.y(4,:),'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

Akzeptierte Antwort

Stephan
Stephan am 29 Apr. 2018
Bearbeitet: Stephan am 29 Apr. 2018
Hi,
typing:
format long
Lets you see more digits. This operation only affects the display and not the calculation.
See also here:
4 digits is the standard option format called short.
Best regards
Stephan

Weitere Antworten (0)

Kategorien

Mehr zu Numerical Integration and Differential Equations finden Sie in Help Center und File Exchange

Produkte

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by