SF = phaseaverf(F,T), if T is a number, returns the phase average of
vector/scalar fields F over a period T.
If T is an integer, SF has length T, and is such that:
SF(i) = averf(F(i:T:end)); for all i between 1 and T
If T is not an integer, then phaseaverf first performs a re-sampling of
the data (linear interpolation). The result has length FLOOR(T).
If T is an arbitrary vector, then performs a loop average of period
T(end), starting from all values of T.
v = loadvec('*.vc7');
sv = phaseaverf(v,linspace(0,4.2,8));