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Fortran Programming Guide

Recognized Reduction Operations

The following table lists the reduction operations that are recognized by f77 and f90.

Table 10-3 Recognized Reduction Operations

Mathematical Operations 

Fortran Statement Templates 

Sum of the elements 

 s = s + v(i)

Product of the elements 

 s = s * v(i)

Dot product of two vectors 

 s = s + v(i) * u(i)

Minimum of the elements 

 s = amin( s, v(i))

Maximum of the elements 

 s = amax( s, v(i))

OR of the elements

do i = 1, n

b = b .or. v(i)

end do

AND of nonpositive elements

b = .true.

do i = 1, n

if (v(i) .le. 0) b=b .and. v(i)

end do

Count nonzero elements 

k = 0

do i = 1, n

if ( v(i) .ne. 0 ) k = k + 1

end do

All forms of the MIN and MAX function are recognized.