FORTRAN: condition on array elements in one column changes corresponding elements in other column

[Mechaero2006]

Hello all,

although it might sound trivial to more experienced users, I am trying to create a code in FORTRAN (preferably f90 or higher) of a n series x 2 columns matrix, where a condition on some elements of column 1, will change the corresponding elements of column 2 (i.e. only those that have the same "i" with the elements affected by the condition). So far I have managed to do this by creating two (2) column arrays containing the elements and by using a simple "where" command I did what I wanted. Could someone please try to inform me how to perform the same job but without spliting the array into two sub-arrays?

Working example code of what I did follows:

program test
    implicit none
    integer::elem
    real,dimension(:),allocatable::A
    real,dimension(:),allocatable::B
    integer::i,j                    

    elem = 10      

    allocate(A(elem))
    allocate(B(elem))

    do i=1,10
        A(i)=i
        end do

    do j=1,10
        B(j)=0
        end do

where (A>=3 .and. A<=6) B = 1

    deallocate(A,B)            

end program test

Thank you in advance for your kind assistance.

 

[IRstuff]

probably something like this in psuedocode:

do blah
A=i
if A>=3 .and. A<=6 then
B=1
else
B=0
end if
end do

FWIW there is a Fortran forum: forum545



TTFN
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http://www.engineering.com/AskForum/aff/32.aspx

faq731-376 forum1529

 

[Mechaero2006]

Thanks for your reply. I'll try your suggestion and repost my question to the forum dedicated to FORTRAN programming.

 

[Mechaero2006]

Found it:

program test
implicit none
integer::elem,i
real,dimension(:,:),allocatable::A
elem = 10
allocate(A(elem,2))
FORALL(I = 1:elem) A(I, 1) = i 
FORALL(I = 1:elem) A(I, 2) = 0
print*,A
where (A(:,1)>=3 .and. A(:,1)<=6) A(:,2) = 1 
print*,A
deallocate(A)
end program test