dissect floating-point numbers into base 2 exponent and mantissa
[f,e]=frexp(x)
real vector or matrix
array of real values, usually in the range 0.5 <= abs(f) < 1.
array of integers that satisfy the equation: x=
f.*2.^e
This function corresponds to the ANSI C function frexp(). Any zeros
in x produce f=0 and
e=0.