ut_convertToMemoryOffset.F90

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!! NOTICE
!!  Copyright 2022 UChicago Argonne, LLC and contributors
!!
!!  Licensed under the Apache License, Version 2.0 (the "License");
!!  you may not use this file except in compliance with the License.
!!
!!  Unless required by applicable law or agreed to in writing, software
!!  distributed under the License is distributed on an "AS IS" BASIS,
!!  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
!!  See the License for the specific language governing permissions and
!!  limitations under the License.
!!
!*******************************************************************************
 
subroutine ut_convertToMemoryOffset(dims, elementCoord, arrayLBound, arrayUBound, memoryOffset)
 
implicit none
integer, intent(IN) :: dims
integer, dimension(1:dims), intent(IN) :: elementCoord, arrayUBound, arrayLBound
integer, intent(OUT) :: memoryOffset
integer, dimension(1:dims) :: elementsToNextIndicy
integer :: i
 
#ifdef DEBUG_MODE
do i = 1, dims, 1
   if (elementCoord(i) < arrayLBound(i) .or. elementCoord(i) > arrayUBound(i)) then
      print *, "[ConvertToMemoryOffset]: Invalid data passed!"
      return
   end if
end do
#endif
 
!This is a count of the number of memory elements between successive array elements.
elementsToNextIndicy(1) = 1
do i = 2, dims, 1
   elementsToNextIndicy(i) = elementsToNextIndicy(i-1) * (arrayUbound(i-1) - arrayLbound(i-1) + 1)
end do
 
!Make a cumulative count of the number of memory elements to reach the user-specified 
!element in each dimension.  Notice that the lower limit of the target array is 
!taken into account so that the caller can pass a non-unit based array.  
memoryOffset = sum( (elementCoord(1:dims) - arrayLBound(1:dims)) * elementsToNextIndicy(1:dims) )
 
end subroutine ut_convertToMemoryOffset