Index must be a positive integer or logical.

I am getting the following error while running the code:

Attempted to access R1_rk4(17501); index must be a positive integer or logical.

Here's a part of my code where the problem lies:

ie1 = 1 + 0.000035/h1;
R1_te = R1_rk4(ie1);
e_R1 = abs(R1_te - R3_te);

Btw, R1_rk4 is a vector, not a matrix. h1 is a constant (time step in the problem). I am trying to access a specific element of the vector R1_rk4 whose size is (1 x 80000).

Any help in removing the error would be much appreciated.

Answer 1

[Azzi Abdelmalek]

The problem is in

R1_te = R1_rk4(ie1);

what is the value of ie1

ie1 must be a positive integer or logical.

[Shashank]

Thanks Azzi. I found out the mistake. The term 0.000035/h1 although turns out to be 17501 when calculating analytically but numerically it will not be an exact integer and that's enough for the indexing routine to complain about it being non-integral.

Answer 2

[Image Analyst]

What's the value of ie1? Is it an integer? Maybe you want

integerIndex = max([1 round(ie1)]);
R1_te = R1_rk4(integerIndex);

[Shashank]

Thanks Image Analyst. I basically need to round off the index to the next possible integer value.

Answer 3

[Walter Roberson]

http://matlab.wikia.com/wiki/FAQ#Why_is_0.3_-_0.2_-_0.1_.28or_similar.29_not_equal_to_zero.3F

[Shashank]

Thanks for the link, Walter. I'll check the wiki section before asking a question here.