Undefined function sgn(z)

close all;

dt = 0.01;%time step

k=1;

m=1;%initial parameters

u1 =1;

u2 =2;

z = u2-u1;

c = sgn(z);

h = c*z;

v=1;

a=1;

tend=10;

t=0;

i=1

while t < tend-2*dt

vh=v(i)-dt*k*h(i)/ (2*m);

h(i+1)= z(i)+ dt*vh;

a(i+1)= -k*h(i+1)/2;

v(i+1)= vh + dt*a(i+1)/2;

i = i+1;

t = t + dt

end

plot(linspace(0,tend,tend/dt),z);

[Stephen23]

Did you actually intend to use sign ?

Answer 1

[Abhishek Kumar]

Hi Advait

There is no function called 'sgn' in matlab. It seems that you wanted to use 'sign' to get the sign of the variable and then make it positive.

you can use to command window to find whether a function exists or not, and if it exists what it does. eg.

>> help sign