XMM-Newton Science Analysis System


dal (dal-1.199) [xmmsas_20230412_1735-21.0.0]

Array

An array is a block that is an n-dimensional array of scalars. An array can be accessed and released with the following procedures:

• array Returns an array handle. Requires a data set handle, the name or number of the array and the access mode.
• release Release the array again. The program should do this as soon as the array is no longer needed.

Once the handle is available, the following properties can be enquired:

• numberOfElements Returns the number of elements in the array.
• dimensions Returns an integer vector with the dimensions of the array.
• numberOfDimensions Returns the number of dimensions of the array.

The data in an array can be accessed via access function. There is a large variety of those to support the different types and dimensions.

• $<$type$>$$<$dimension$>$Data Returns a pointer to the data in the array. Requires an array handle.

The following example illustrates how to change the values in an array.

program modifyColumn
  use dal
  type(DataSetT) :: set
  type(ArrayT) :: arr
  integer(kind=int32), dimension(:,:), pointer :: x

  set = dataSet("test.dat",Modify)
  arr = array(set,"test")
  x => int32Array2Data(arr)
  x = 124
  call release(arr)
  call release(set)
end program

To reduce the size of the array that is accessed in one go (and thereby reducing memory usage), one can select a certain range:

• arraySeek Set the range of interest. Requires an array handle and two vectors of integers, indicating the starting position and the size of the range of interest.

Note: the current DAL does not support the seek function.