This syntax does not do what you think it does:
phaseerror == 0.0000000001||0.000000001||0.00000001||0.0000001||0.000001||0.00001||0.0001||0.001||0.01||0.1
As the documentation explains, logical operators are binary functions. We also know that equal-level operators are evaluated from left to right (just like in mathematics), so what you wrote is equivalent to (I added parentheses to help you):
((...(((phaseerror == 0.0000000001) || 0.000000001) || 0.00000001) ... ) || 0.1
which becase each of the values (except possibly the first comparison) is non-zero, is exactly equivalent to
((...(((phaseerror == 0.0000000001) || true) || true) ... ) || true
which clearly simplfies down to
(phaseerror == 0.0000000001) || true
which is clearly just
true
In any case, testing for equivalence of floating point numbers is not recommended (search this forum for "binary floating point error" to know why). You need to allow for the accumulated floating point error. I don't know what magnitude your data are, but judging by the stepsize you need to pay very careful attention to eps and ensure that your operations are numerically stable (e.g. no subtraction of similar values, etc.).
Note that your code can be simplified by using basic MATLAB indexing and arrays more effectively: everywhere you access one-element-at-a-time followed by concatenation you should simply refer to multiple elements at once. I.e. instead of this
[mod(d,wavelround(1)),mod(d,wavelround(2)),mod(d,wavelround(3))]
you just need
mod(d,wavelround(1:3))
and similarly for all the rest of your code.
To avoid inefficient code and some pointless bugs you should preallocate the output array before the loop:
You might also find this useful:
