Matlab Invalid Data Argument

 u = @(t) (t>=0);
 r = @(t) t.*u;
 x = @(t) r(t)-r(t-1)-3*u(t-1)-2*r(t-3)-r(t-4)-r(t-5)-u(t-7);
 t = [-2:0.01:7];
plot(t,x)

Why am a getting invalid data argument as error when plotting>

[SL: formatted code as code]

Answer 1

[Steven Lord]

Let's look at your code section by section.

u = @(t) (t>=0);
r = @(t) t.*u;

This will not work as written. You cannot multiply a number and a function handle. What you can do instead is to multiply a number and the result of evaluating a function handle.

r = @(t) t.*u(t);

In the next section there is a similar problem.

 x = @(t) r(t)-r(t-1)-3*u(t-1)-2*r(t-3)-r(t-4)-r(t-5)-u(t-7);
 t = [-2:0.01:7];
plot(t,x)

The plot function will not accept a function handle as its second input, but it can accept the result of evaluating a function handle.

plot(t, x(t))

[Callum Stewart]

Thanks this explains a lot thanks

Answer 2

[Karolis Poskus]

Hello,

To plot anonymous function use:

doc fplot