COR = corrf(F, DIM) returns the correlation function of the scalar
field F along the dimension DIM (with DIM=1, 2, or 'x','y', for
correlation along the 'X' or 'Y' direction). If F is an array of
scalar fields, COR returns the average of the correlation functions of
each field. COR also contains various integral scales computed from the
correlation function (see below).
COR is a structure which contains the following fields:
r: separation length
f: correlation function
unitr: unit of separation length
unitf: unit of correlation function
namef: name of correlation function
isinf: integral scale, computed as the integral of f up to infty
r5: scale at which f(r5)=0.5 (linearly interpolated)
is5: integral scale, computed as the integral of f from 0 to r5
r2, is2, r1, is1, r0, is0 : idem as r5, is5, for crossovers
at 0.2, 0.1 and 0 respectively
COR = corrf(F, DIM, 'norm') normalizes the correlation function, so
that f = 1 at r = 0.
For a vector field V, corrf(vec2scal(V,'ux'),'x') and
corrf(vec2scal(V,'uy'),'y') are the longitudinal correlation functions,
and corrf(vec2scal(V,'ux'),'y') and corrf(vec2scal(V,'uy'),'x') are the
Note that the convergence of the correlation function is not garanteed,
especially at large separations r, for which very few data points are
available to compute the correlation.
If the crossover scales are not defined (i.e. if the correlation
function does not decrease enough for large r), NaNs (not a number)
are returned, and a warning is issued. Use corrf(...,'nowarning') to
ignore these warnings.
COR = corrf(..., 'verbose') also displays the computation in progress.
If no output argument, the correlation function is plotted.
v = loadvec('B00001.VEC');
cor = corrf(vec2scal(v,'vx'),'x');
plot(cor.r, cor.f, 'o-');
vec2scal, tempcorrf, statf, histf, vsf, specf.
Published output in the Help browser