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dim_product

Computes the product of a variable's rightmost dimension at all other dimensions.

Prototype

	function dim_product (
		x  : numeric   
	)

	return_val  :  float or double

Arguments

x

A variable of numeric type and any dimensionality.

Return value

The output will be double if x is double, and float otherwise.

The output dimensionality is the same as the first n-2 dimensions of the input variable. That is, the dimension rank of the input variable will be reduced by one.

Description

The dim_product function computes the product of all elements of the n-1th (rightmost) dimension for each index of the dimensions 0...n-2. Missing values are ignored.

Use dim_product_n if you want to specify which dimension(s) to do the average across.

See Also

product, dim_product_n, dim_median, dim_stddev, dim_num, dim_rmsd, dim_rmvmean, dim_rmvmed, dim_standardize, dim_stat4, dim_stddev, dim_variance, copy_VarMeta

Examples

Example 1

Create a variable, q, of size (3,5,10) array. Then calculate the product of the rightmost dimension.

    q   = random_uniform(-20,100,(/3,5,10/))
    qav = dim_product(q)   ;==>  qav(3,5)
Example 2

Let x be of size (ntim,nlat,mlon) and with named dimensions "time", "lat" and "lon", respectively. Then, for each time and latitude, the the 'zonal product' (i.e., product of all non-missing longitudes) is:

    xProLon = dim_product( x )    ; ==> xProLon(ntim,nlat)
Example 3

Let x be defined as in Example 2: x(time,lat,lon). Compute the product over time at each latitude/longitude grid point. Use NCL's Named Subscripting to reorder the input array such that "time" is the rightmost dimension.

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

    xProTime = dim_product( x(lat|:, lon|:, time|:) )    ; ==> xProTime(nlat,nlon)

    xProTime = dim_product_n( x, 0 )                     ; no reordering needed