Manual Reference Pages  - maxloc (3fortran)

NAME

MAXLOC(3) - [ARRAY:LOCATION] Location of the maximum value within an array

SYNOPSIS

result = maxloc(array [,mask]) | maxloc(array [,dim] [,mask])

         NUMERIC function maxloc(array, dim, mask)

NUMERIC,intent(in) :: array(..) integer(kind=**),intent(in),optional :: dim logical(kind=**),intent(in),optional :: mask(..)

CHARACTERISTICS

o a kind designated as ** may be any supported kind for the type
o NUMERIC designates any intrinsic numeric type and kind.

DESCRIPTION

MAXLOC(3) determines the location of the element in the array with the maximum value, or, if the DIM argument is supplied, determines the locations of the maximum element along each row of the array in the DIM direction.

If MASK is present, only the elements for which MASK is .true. are considered. If more than one element in the array has the maximum value, the location returned is that of the first such element in array element order.

If the array has zero size, or all of the elements of MASK are .false., then the result is an array of zeroes. Similarly, if DIM is supplied and all of the elements of MASK along a given row are zero, the result value for that row is zero.

OPTIONS

o ARRAY : Shall be an array of type integer, real, or character.
o DIM : (Optional) Shall be a scalar of type integer, with a value between one and the rank of ARRAY, inclusive. It may not be an optional dummy argument.
o MASK : Shall be an array of type logical, and conformable with ARRAY.

RESULT

If DIM is absent, the result is a rank-one array with a length equal to the rank of ARRAY. If DIM is present, the result is an array with a rank one less than the rank of ARRAY, and a size corresponding to the size of ARRAY with the DIM dimension removed. If DIM is present and ARRAY has a rank of one, the result is a scalar. In all cases, the result is of default integer type.

The value returned is reference to the offset from the beginning of the array, not necessarily the subscript value if the array subscripts do not start with one.

EXAMPLES

sample program

    program demo_maxloc
    implicit none
    integer      :: ii
    integer,save :: i(-3:3)=[(abs(abs(ii)-50),ii=-3,3)]
    integer,save :: ints(3,5)= reshape([&
       1,  2,  3,  4,  5, &
       10, 20, 30, 40, 50, &
       11, 22, 33, 44, 55  &
    ],shape(ints),order=[2,1])

write(*,*) maxloc(ints) write(*,*) maxloc(ints,dim=1) write(*,*) maxloc(ints,dim=2) ! when array bounds do not start with one remember MAXLOC(3) returns ! the offset relative to the lower bound-1 of the location of the ! maximum value, not the subscript of the maximum value. When the ! lower bound of the array is one, these values are the same. In ! other words, MAXLOC(3) returns the subscript of the value assuming ! the first subscript of the array is one no matter what the lower ! bound of the subscript actually is. write(*,’(g0,1x,g0)’) (ii,i(ii),ii=lbound(i,dim=1),ubound(i,dim=1)) write(*,*)maxloc(i)

end program demo_maxloc

Results:

     >     3       5
     >     3       3       3       3       3
     >     5       5       5
     >  -3 47
     >  -2 48
     >  -1 49
     >  0 50
     >  1 49
     >  2 48
     >  3 47

STANDARD

Fortran 95

SEE ALSO

o FINDLOC(3) - Location of first element of ARRAY identified by MASK along dimension DIM matching a target
o MINLOC(3) - Location of the minimum value within an array
o MAXVAL(3)
o MINVAL(3)
o MAX(3)
fortran-lang intrinsic descriptions


Nemo Release 3.1 maxloc (3fortran) April 28, 2024
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