As far as anything that handles numeric data is concerned, 7.8651e+04 and 78651 are the same. The formatting is merely a matter of display.
I'm going to go out on a limb and assume that you're doing something to create indexes into an array and that you're generating non-integer indices. In that case, you can probably just do
index=round(index);
or similar.
Otherwise, share some info about the code and the specific error message you're getting.
