SUM Function

Sums an array of n dimensions over one of its dimensions.

Usage

result = SUM (array, dim)

Input Parameters

array—An array of n dimensions of any data type except string.

dim—The dimension over which array is summed. The dim parameter must be a number in the range 0 £ dim £ (n–1), where n is the number of dimensions in array.

Returned Value

result—A scalar value equal to the sum of the array elements over the specified dimension.

Keywords

None.

Discussion

If array is either a single or double-precision complex, or a double-precision floating-point data type, the result is of the same data type. SUM returns a single-precision floating-point value for all other acceptable data types.

Example

This example illustrates SUM being used for a variety of arrays of different sizes.

; Create two arrays, array1, a one-dimensional array with two 

; elements and array2, a two-dimensional array with four

; elements, using FINDGEN.

array1 = FINDGEN(2)

array2 = FINDGEN(2,2)

; Print the arrays then sum each array over each of its dimensions

; and print the result.

PRINT, array1

; PV-WAVE prints: 0.00000      1.00000

PRINT, array2

; PV-WAVE prints the following:

; 0.00000      1.00000

; 2.00000      3.00000

PRINT, SUM(array1, 0)

; PV-WAVE prints: 1.00000

PRINT, SUM(array2, 0)

; PV-WAVE prints: 1.00000      5.00000

PRINT, SUM(array2, 1)

; PV-WAVE prints: 2.00000      4.00000

See Also

AVG, MAX, MEDIAN, MIN, STDEV, TOTAL