mo_moment::central_moment Interface Reference

R-central moment. More...

Public Member Functions
real(sp) function	central_moment_sp (x, r, mask)
real(dp) function	central_moment_dp (x, r, mask)

Detailed Description

R-central moment.

Calculates the central moment of a vector, i.e. the r-central moment of a series of numbers:

\[ \mu_r = \sum_i\frac{(x_i-\bar x)^r}{N} \]

Note that the variance is the second central moment: variance(x) = central_moment(x,2)
If an optinal mask is given, the average is only over those locations that correspond to true values in the mask. x can be single or double precision. The result will have the same numerical precision.

Example

vec = (/ 1., 2, 3., 4., 5., 6. /)
m   = central_moment(vec, 2, mask=(vec >= 0.))
--> m = 2.91666

See also example in pf_tests directory.

Literature

1. LH Benedict & RD Gould, Towards better uncertainty estimates for turbulence statistics. Experiments in Fluids 22, 129-136, 1996

Parameters

[in]	real(sp/dp) :: dat(:)	1D-array with input numbers.
[in]	integer(i4) :: r	Order of the central moment, i.e. r=2 is variance.
[in]	logical, optional :: mask(:)	1D-array of logical values with size(dat). If present, only those locations in dat corresponding to the true values in mask are used.

Return values

real(sp/dp) :: central_moment

R-th central moment of elements in dat.

Note

Input values must be floating points.

Author

Matthias Cuntz

Date

Nov 2011

Definition at line 162 of file mo_moment.f90.

Member Function/Subroutine Documentation

central_moment_dp()

real(dp) function mo_moment::central_moment::central_moment_dp	(	real(dp), dimension(:), intent(in)	x,
		integer(i4), intent(in)	r,
		logical, dimension(:), intent(in), optional	mask
	)

Definition at line 734 of file mo_moment.f90.

central_moment_sp()

real(sp) function mo_moment::central_moment::central_moment_sp	(	real(sp), dimension(:), intent(in)	x,
		integer(i4), intent(in)	r,
		logical, dimension(:), intent(in), optional	mask
	)

Definition at line 773 of file mo_moment.f90.

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The documentation for this interface was generated from the following file:

• src/mo_moment.f90