Why do I get the error 'Subscript indices must either be real positive integers or logicals ' for the below code?

xa = (x-xc_t(t)+bx_t(t))/(sr2*betax_t(t));

[Azzi Abdelmalek]

Can you give more details?

[dpb]

why? I'd guess most likely because you start with t==0

Don't use a time value as the indexing expression; use a time step number and an associated vector of actual times.

[Summer]

x, xc_t, bx_t, and betax_t are variables, while sr2 is the square root of 2.

[Summer]

True. Time starts at t=0 and then increases. The values of t are already being read from a text file, which was already saved as a 1x61 vector.

I'll check if indexing using the time step number would resolve it.

Thx

Answer 1

[Image Analyst]

t is either 0, negative, or some fractional value, like 3.00023 or something. If, before that line you put

format long
t

what does it show in the command window? How did you define t in the first place?

[Summer]

t starts at 0 in my case. Some values are indeed fractional. Time was read from another text file and imported as a 61x1 vector.