Declaring matrix dimensions from an input file

[dimis414]

Assuming that in a subroutine we use a matrix named as VOL(IDI,IDI).
Instead of declaring IDI in PARAMETER command, i.e: PARAMETER (IDI=10), is it possible to declare it at the input file, so the matrix dimensions whould change depending on the input file?

 

[xwb]

Depends on which version of Fortran you are using. F77 no, F90 onwards yes.

    real, dimension(:,:), allocatable:: vol
    integer:: idi, status
    ...
    ! to get the value of idi
    read(channel, *) idi
    ! to allocate the space
    allocate(vol(idi,idi))
    ...
    ! when you've finished with it
    deallocate(vol, stat = status)

 

[dimis414]

That was really helpful!!!!
Thanks xwb