This now runs.
One problem was that ‘deriv’ is actually a reserved name, so I changed it. Also the ‘guess’ function was incorrectly coded, and ‘xmesh’ needs to be a vector of more than two elements.
Try this —
xmesh = linspace(0, 200, 5000);
guess = @(x) [(x+1); -(x+1); (2-x); (2+x)];
solinit = bvpinit(xmesh,guess);
sol = bvp4c(@bvpderiv, @bcs,solinit);
figure
plot(sol.x,sol.y)
grid
legend(string(Subs), 'Location','best')
function dydx = bvpderiv(x,y)
c=1;a=1;
dydx = [y(2)
y(3)
y(4)
(c/(a*x.^2 -y(1)).^2)];
end
function res = bcs(ya,yb)
res = [ ya(1)
ya(2)
yb(3)
yb(4)];
end
If the eventual desire is to have ‘a’ and ‘C’ as arguments to ‘bvpderiv’, rather than hard-coding them, code it as —
function dydx = bvpderiv(x,y,a,c)
dydx = [y(2)
y(3)
y(4)
(c/(a*x.^2 -y(1)).^2)];
end
and then call it as —
@(x,y)bvpderiv(x,y,a,c)
with the parameters previously defined in the workspace.
.
