Plot a variable with different values at different time intervals.

Hi

I have a table below that assigns different values of r at different time interval. How can I do this please?

[Luna]

What have you done so far? What does it mean 0 - < 1 ? From 0 to 1 ?

Answer 1

[madhan ravi]

Logical indexing is more efficient :

t=0:.001:8;
r=zeros(size(t));
r(t>=0 & t<1)=100;
r(t>=1 & t<4)=250;
r(t>=4 & t<6)=330;
r(t>=6 & t<8)=100;
r(t==8)=0;
plot(t,r)

[Sean Watts]

Can the same thing be done, but instead of linear answers of 100,250... can the result= a variable resulting form the current time itself?

r(t>=0 & t<1)=(t/100)^2

[madhan ravi]

Not sure what you're asking, perhaps you mean:

idx = t>=0 & t<1;
r(idx)=(t(idx)/100)^2

[Sean Watts]

Thanks for reply,

I am very new to Matlab but have to use it for a module in my civ eng degree.

I essentially need to make a modulating function (phi(t)) to apply to a larger variable.

with t=0:20 seconds and beta=9/10; t1=2.5/beta; t2=11.5/beta;

boundarys;

phi(t)= (t/t1).^2 when t<t1

phi(t)= 1 when t1=<t=<t2

phi(t)= exp(-beta*(t-t2) when t>t2