Question about a script

I wrote a script with 3 parts to simulate a hockey puck bouncing around on a plot.

%Part 1: main body of script

hf=figure;
ha=axes('Parent',hf);
hp=plot(ha,0,0,'o','LineWidth',5);
axis([0 5 0 2]);

%set(hp,'XData',1:10)
pos = [0,0]
vel = [1,1]
for step = 1:.02:1000
  set (hp,'XData',pos(1))
  set (hp,'YData',pos(2))
  pos = pos_vel(pos,vel)
 [pos,vel]= Reflect(pos,vel)

Part 2: kinematics function to update pos and vel of puck

function [ new_pos ] = pos_vel(pos,vel,dt)
%UNTITLED3 Summary of this function goes here
%   Detailed explanation goes here
dt = .5;
new_pos = pos + vel*dt

end

Part 3: keeps puck in boundaries of (x,y) = from (0,0) to (5,2)

function [pos,vel] = Reflect(pos,vel)
%UNTITLED4 Summary of this function goes here
%   Detailed explanation goes here
if pos(1) >= 5
 pos(1) = 10-pos(1)
 vel(1) = -vel(1)
end
if pos(1)<=0
 pos(1) = -pos(1)
 vel(1) = -vel(1)
end
if pos(2) >= 2
 pos(2) = 4-pos(2)
 vel(2) = -vel(2)
end
if pos(2)<= 0
 pos(2) = -pos(2) 
 vel(2) = -vel(2)
end
end

When I try to run I get msg: "Undefined function 'pos_vel' for input arguments of type 'double'.

Error in Lab_13_Revised (line 12) pos = pos_vel(pos,vel)"

Is this a problem with the file path or with the code? I have tried the mkdir and addpath commands and it still is not working.

Answer 1

[Simon]

Hi!

You may not mix a script with a function in one file! If you want to write a function called "pos_vel", you have to save it in a separate file called "pos_vel.m". The function file must be on the path. In a script file Matlab cannot call a function defined in the same file!