Array indices must be positive integers or logical values.

I'm trying to create a loop that plots the function for each t value on the same graph, I am getting an "Array indices must be positive integers or logical values." error.

t = [1 24 48 72];
  x = linspace(0,1,4);
  for ii = length(t)
  u=1.656e-5;
  c(x)=(0.5).*erfc(x./(2.*sqrt(u.*t)));
  plot (x, c) 
  end

Answer 1

[Star Strider]

This will run:

t = [1 24 48 72];
x = linspace(0,1,4);
for ii = length(t)
    u=1.656e-5;
    c(ii)=(0.5).*erfc(x(ii)./(2.*sqrt(u.*t(ii))));
    plot (x, c)
end

although you may want to experiment with it.

Note that I subscripted ‘x’ and ‘t’, since I assume that is what you intend.

[matlabgod]

Hi thanks for the quick response, but now I'm getting "Error using plot Vectors must be the same length." error.

[Star Strider]

My pleasure.

You must be using different size vectors for ‘t’ and ‘x’.

My code works with the code you posted.