array_range

This repository provides user-defined types array_range{1|2|3}d_type to improve the manipulation of bounds of Fortran arrays.

Fortran's array allows us to define in any range. When executing a do-loop, the lower and upper bounds of arrays may be acquired as follows:

real(real64) :: val(0:10, 0:10)
integer :: lbnd(2), ubnd(2)

lbnd = lbound(val)
ubnd = ubound(val)

do j = lbnd(2), ubnd(2)
do i = lbnd(1), ubnd(1)
    ...
end do
end do

Introducing array_range{1|2|3}d_type makes it easier to acquire and reference the bounds:

use :: array_range

real(real64) :: val(0:10, 0:10)
type(array_range2d_type) :: range

range = to_array2d_range([lbound(val), ubound(val)])

do j = range%rank(2)%lower, range%rank(2)%upper
do i = range%rank(1)%lower, range%rank(1)%upper
    ...
end do
end do

When defining user-defined types containing multidimensional arrays, further improvement can be achieved by defining new types and procedures by referencing array_range{1|2|3}d_type such as:

type(vector2d) :: vec
! contains 2 multidimensional arrays

type(vector2d_range_type) :: range
! vector2d_range_type is defined as
! type :: vector2d_range_type
!     type(array_range2d_type) :: x,y
! end type

range = vec%get_range()
! get_range is a type-bound procedure to return vector2d_range_type object

do j = range%x%rank(2)%lower, range%x%rank(2)%upper
do i = range%x%rank(1)%lower, range%x%rank(1)%upper
    ...
end do
end do

do j = range%y%rank(2)%lower, range%y%rank(2)%upper
do i = range%y%rank(1)%lower, range%y%rank(1)%upper
    ...
end do
end do

usage

Get the code

To get the code, execute the following commnad:

git clone https://github.com/degawa/array_range.git
cd array_range

Build with fpm

To build the library using fpm, execute the following command:

fpm build

Reference from other projects

To refer array_range from your projects, simplify copy the src directory to your project directory and add use statement to the modules, functions, and subroutines that refers user-defined types defined in array_range.

use :: array_range

To refer array_range from fpm projects, add the following to your fpm manifest.

[dependencies]
array_range = {git = "https://github.com/degawa/array_range.git"}