undefined function 'f'

1 view (last 30 days)
Titas Chattopadhyay
Titas Chattopadhyay on 31 Mar 2020
Commented: Ameer Hamza on 31 Mar 2020
tmesh = linspace(0,pi/2,5);
solinit = bvpinit(tmesh, @f);
sol = bvp4c(@odefun, @bcfun, solinit);
plot(sol.x, sol.y, '-o');
FUNCTION
function dzdt = odefun(t,z)
dzdt = zeros(2,1);
dzdt = [z(2)+z(1)];
end
% boundary conditions
function res = bcfun(za, zb)
res = [za(1) zb(pi/2)-2]
end
% Initial guess
function g = f(t)
g = [sin(t) cos(t)];
end
error unrecognized function or variable 'f'
  3 Comments
Titas Chattopadhyay
Titas Chattopadhyay on 31 Mar 2020
So, I have to make 3 function files for func ,bcs and ics. Right?

Sign in to comment.

Accepted Answer

Ameer Hamza
Ameer Hamza on 31 Mar 2020
Edited: Ameer Hamza on 31 Mar 2020
Either write all the functions in one file like this. (Also note that I have made few changes in your code.)
tmesh = linspace(0,pi/2,5);
solinit = bvpinit(tmesh, @f);
sol = bvp4c(@odefun, @bcfun, solinit);
plot(sol.x, sol.y, '-o');
function dzdt = odefun(t,z)
dzdt = zeros(2,1);
dzdt = [z(2); z(1)]; % <----- This should be a 2x1 vector
end
% boundary conditions
function res = bcfun(za, zb)
res = [za(1); zb(2)-2]; % <---- boundary conditions are written like this, zb(pi/2) is invalid
end
% Initial guess
function g = f(t)
g = [sin(t) cos(t)];
end
Or create 4 files like this.
main_script:
tmesh = linspace(0,pi/2,5);
solinit = bvpinit(tmesh, @f);
sol = bvp4c(@odefun, @bcfun, solinit);
plot(sol.x, sol.y, '-o');
odefun.m:
function dzdt = odefun(t,z)
dzdt = zeros(2,1);
dzdt = [z(2); z(1)];
end
bcfun.m:
% boundary conditions
function res = bcfun(za, zb)
res = [za(1); zb(2)-2];
end
f.m:
% Initial guess
function g = f(t)
g = [sin(t) cos(t)];
end
  2 Comments
Ameer Hamza
Ameer Hamza on 31 Mar 2020
Glad to be of help.

Sign in to comment.

More Answers (0)

Categories

Find more on Operators and Elementary Operations in Help Center and File Exchange

Community Treasure Hunt

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

Start Hunting!

Translated by