count

Date:

10-12-2011

NAME

COUNT - Counts the number of true array elements

SYNOPSIS

COUNT ([MASK=]mask [,[DIM=]dim, [KIND=]kind])

IMPLEMENTATION

Cray Linux Environment (CLE)

STANDARDS

Fortran

DESCRIPTION

The COUNT intrinsic function counts the number of true array elements of argument mask along dimension dim. It accepts the following arguments:

mask

The mask argument must be of type logical. It must not be a scalar.

dim

The dim argument must be a scalar. It is an integer with a value in the range 1 <= dim <= n, where n is the rank of mask. The corresponding actual argument must not be an optional dummy argument.

kind

The kind argument determines the kind type of the return result. If this argument is not specified, the return result is of type default integer.

  • See the RETURN VALUES section for more information

  • This argument must be a scalar integer initialization expression.

COUNT is a transformational function. The name of this intrinsic cannot be passed as an argument.

RETURN VALUES

The result is type integer. It is a scalar result if dim is absent or if mask has rank 1. Otherwise, the result is an array of rank n-1 and of shape

(d1, d2, ..., ddim-1, ddim+1, ..., dn)

where

(d1, d2, ..., dn)

is the shape of mask.

The result of COUNT(mask) has a value equal to the number of TRUE elements of mask or has the value 0 if mask is a zero-sized array.

If mask has rank 1, COUNT(mask, dim) has a value equal to that of COUNT(mask). Otherwise, the value of element

(s1, s2, ..., sdim-1, sdim+1, ..., sn)

of COUNT(mask, dim) is equal to

COUNT(MASK (s1, s2, ..., sdim-1, : , sdim+1, ..., sn))

EXAMPLES

Example 1:

  • COUNT((/.TRUE.,.FALSE.,.TRUE./)) yields 2.

  • COUNT(mask) yields 0 when mask is a zero-sized array.

Example 2: Assume that B is the following array:

| 1 3 5 |
| 2 4 6 |

C is the following array:

| 0 3 5 |
| 7 4 8 |

  • COUNT(B.NE.C) yields 3.

  • COUNT(B.NE.C,DIM=1) yields [2,0,1].

  • COUNT(B.NE.C,DIM=2) yields [1,2].

  • COUNT(C.EQ.1) yields 0 because there are no true elements in the mask.

Example 3: Assume that array N is as follows:

| 0 1 2 3 |
| 4 5 6 7 |
| 8 9 0 1 |

In an array section reference, you can expect the following results:

  • COUNT((N(2:3,2:4).NE.0)) yields 5.

  • COUNT((N(2:3,2:4).NE.0),DIM=1) yields [2,1,2].

  • COUNT((N(2:3,2:4).NE.0),DIM=2) yields [3,2].