pic_sorting_ord_sort Submodule

The generic subroutine implementing the ORD_SORT algorithm to return an input array with its elements sorted in order of (non-)decreasing value. Its use has the syntax:

 call ord_sort( array[, work, reverse] )

with the arguments:

• array: the rank 1 array to be sorted. It is an intent(inout) argument of any of the types integer(int8), integer(int16), integer(int32), integer(int64), real(real32), real(real64), real(real128), character(*), type(string_type), type(bitset_64), type(bitset_large). If both the type of array is real and at least one of the elements is a NaN, then the ordering of the result is undefined. Otherwise it is defined to be the original elements in non-decreasing order.

• work (optional): shall be a rank 1 array of the same type as array, and shall have at least size(array)/2 elements. It is an intent(out) argument to be used as “scratch” memory for internal record keeping. If associated with an array in static storage, its use can significantly reduce the stack memory requirements for the code. Its value on return is undefined.

• reverse (optional): shall be a scalar of type default logical. It is an intent(in) argument. If present with a value of .true. then array will be sorted in order of non-increasing values in stable order. Otherwise index will sort array in order of non-decreasing values in stable order.

Example

    ...
    ! Read arrays from sorted files
    call read_sorted_file( 'dummy_file1', array1 )
    call read_sorted_file( 'dummy_file2', array2 )
    ! Concatenate the arrays
    allocate( array( size(array1) + size(array2) ) )
    array( 1:size(array1) ) = array1(:)
    array( size(array1)+1:size(array1)+size(array2) ) = array2(:)
    ! Sort the resulting array
    call ord_sort( array, work )
    ! Process the sorted array
    call array_search( array, values )
    ...