Fortran - Reduction Functions


Advertisements

The following table describes the reduction functions:

Function Description
all(mask, dim) It returns a logical value that indicates whether all relations in mask are .true., along with only the desired dimension if the second argument is given.
any(mask, dim) It returns a logical value that indicates whether any relation in mask is .true., along with only the desired dimension if the second argument is given.
count(mask, dim) It returns a numerical value that is the number of relations in mask which are .true., along with only the desired dimension if the second argument is given.
maxval(array, dim, mask) It returns the largest value in the array array, of those that obey the relation in the third argument mask, if that one is given, along with only the desired dimension if the second argument dim is given.
minval(array, dim, mask) It returns the smallest value in the array array, of those that obey the relation in the third argument mask, if that one is given, along with only the desired dimension if the second argument DIM is given.
product(array, dim, mask) It returns the product of all the elements in the array array, of those that obey the relation in the third argument mask, if that one is given, along with only the desired dimension if the second argument dim is given.
sum (array, dim, mask) It returns the sum of all the elements in the array array, of those that obey the relation in the third argument mask, if that one is given, along with only the desired dimension if the second argument dim is given.

Example

The following example demonstrates the concept:

program arrayReduction

   real, dimension(3,2) :: a 
   a = reshape( (/5,9,6,10,8,12/), (/3,2/) ) 
   
   Print *, all(a>5)
   Print *, any(a>5)
   Print *, count(a>5)
   Print *, all(a>=5 .and. a<10)
  
end program arrayReduction

When the above code is compiled and executed, it produces the following result:

F
T
5
F

Example

The following example demonstrates the concept:

program arrayReduction
implicit none

   real, dimension(1:6) :: a = (/ 21.0, 12.0,33.0, 24.0, 15.0, 16.0 /)
   Print *, maxval(a)
   Print *, minval(a)
   Print *, sum(a)
   Print *, product(a)
   
end program arrayReduction 

When the above code is compiled and executed, it produces the following result:

33.0000000    
12.0000000    
121.000000    
47900160.0  
fortran_arrays.htm
Advertisements