MATLAB: Help with plotting in a bvp4c solver

bvp4codepiecewiseplot

Hello! I am having trouble plotting a function in bvp4c. I managed to plot the solution of the ODE, but I would like to multiply the solution with another piecewise defined function and then get a plot of them as well.
When I run the code I get the following error:
Operands to the || and && operators must be convertible to logical scalar values.
Error in xfgn>F (line 43)
if     (xint >= 0) && (xint <= 1.25)
Error in xfgn (line 10)
Sxint2=Sxint*1000/8*F(xint);
Any suggestions on how to fix this problem with the piecewise defined function F(xint)? Thanks.
function bvp4
xlow=0;
xhigh=20;
solinit=bvpinit(linspace(xlow,xhigh,1000),[0 0]);
sol = bvp4c(@bvp4ode,@bvp4bc,solinit);
xint=linspace(xlow,xhigh);
Sxint=deval(sol,xint);
Sxint1=sqrt(Sxint);
Sxint2=Sxint*1000/8*F(xint);
plot(xint,Sxint2(1,:))
function dydx = bvp4ode(x,y)
dydx = [y(2)/(H(x)*H(x));      (G(x)+125*f(x)*y(1)-9.47646*H(x))/(35*(f(x)/8))];
function res = bvp4bc(ya,yb)
res = [ya(1);        yb(1)];
function fval = f(x)
if     (x >= 0) && (x <= 1.25)
    fval = 0.0152;
elseif  (x > 1.25) && (x <= 20)
    fval = 0.0232;
end
function Gval = G(x)
if     (x >= 0) && (x <= 1.25)
    Gval = 0.15*1000*9.81*0.2*0.000966;
elseif  (x > 1.25) && (x <= 20)
    Gval = -0.25*1000*9.81*0.05*0.000966;
end
function Hval = H(x)
if     (x >= 0) && (x < 1.1)
    Hval = 0.2;
elseif  (x >= 1.1) && (x <= 1.25)
    Hval = -x+1.3;
elseif  (x > 1.25) && (x <= 20)
     Hval = 0.05;
end
function Fval = F(xint)
if     (xint >= 0) && (xint <= 1.25)
    Fval = 0.0152;
elseif  (xint > 1.25) && (xint <= 20)
     Fval = 0.0232;
end

Best Answer

"xint" is a vector - thus Fval must be applied in a loop over the size of "xint".
Best wishes
Torsten.
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