find discretization steps
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I have data files F_j, each containing a list of numbers with an unknown number of decimal places. Each file contains discretized measurements of some continuous variable and
I want to find the discretization step d_j for file F_j 

A solution I could come up with: for each F_j, find the number n_j of decimal places, multiply each number in F_j  with 10^{n_j} to obtain integers and then find the greatest common divisor of the entire list. My questions:
1) an elegant way to find n_j with matlab
2) finding the gcd of a long list of integers seems hard - do you have any better idea?











 