NCL Website header
NCL Home > Documentation > Functions > General applied math, Statistics

dim_cumsum_Wrap

Calculates the cumulative sum along the rightmost dimension and retains metadata.

Available in version 4.3.0 and later.

Prototype

load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl"

	function dim_cumsum_Wrap (
		x    : numeric,  
		opt  : integer   
	)

	return_val [dimsizes(x)] :  float or double

Arguments

x

A variable of numeric type and any dimensionality.

opt

Option for how to treat _FillValue

  • opt = 0 ; when _FillValue is encountered no additional summing will be performed.
  • opt = 1 ; when _FillValue is encountered set element to _FillValue and resume summing
  • opt = 2 ; treat _FillValue as numeric zero when summing

Return value

The same type and dimensionality as x.

Description

This function calculates the cumulative sum of all elements of the n-1th (rightmost) dimension for each index of the dimensions 0...n-2. A wrapper function. Missing values are treated differently as specified by opt. Use dim_cumsum_n_Wrap if you want to specify which dimension to do the average across.

See Also

dim_acumrun_n, dim_cumsum_n_Wrap, cumsum, dim_cumsum, dim_cumsum_n, dim_rmvmean, dim_rmvmed

Examples

Example 1: When no _FillValue are encountered all three options return the same result.

  x        = (/1,2,3,4,5/)
  x_sum    = sum(x)            ; result 15        
  x_cumsum = dim_cumsum_Wrap(x, 0)  ; result (/1  3  6  10  15/)
  x_cumsum = dim_cumsum_Wrap(x, 1)  ; result (/1  3  6  10  15/)
  x_cumsum = dim_cumsum_Wrap(x, 2)  ; result (/1  3  6  10  15/)
Example 2: When one or more _FillValue are encountered, each option yields a different answer.
  x        = (/1,2,-999,4,5/)
  x@_FillValue = -999 
  x_sum    = sum(x)            ; result 12
  x_cumsum = dim_cumsum_Wrap(x, 0)  ; result (/1  3 -999 -999 -999/)
  x_cumsum = dim_cumsum_Wrap(x, 1)  ; result (/1  3 -999    7   12/)
  x_cumsum = dim_cumsum_Wrap(x, 2)  ; result (/1  3    3    7   12/)
Example 3: Let p(time,lat,lon), use dimension reordering to make "time" the rightmost dimension and calculate cumulative sums at each time. The opt argument can be set by the user.

Note: in V5.1.1, you will be able to use dim_cumsum_n_Wrap to avoid having to reorder your data.

  p_cumsum = dim_cumsum_Wrap(p(lat|:,lon|:,time|:), opt)  

  p_cumsum = dim_cumsum_n_Wrap(p, opt, 0)     ; no reordering needed