Array Inquiry Intrinsics

These intrinsics allow the user to quiz arrays about their attributes and status and are most often applied to dummy arguments in procedures. Consider the declaration:

    REAL, DIMENSION(-10:10,23,14:28) :: A

the following inquiry intrinsics are available,

• LBOUND(SOURCE[,DIM])

  Returns a one dimensional array containing the lower bounds of an array or, if a dimension is specified, a scalar containing the lower bound in that dimension. For example,

  • LBOUND(A) is (/-10,1,14/) (array);
  • LBOUND(A,1) is -10 (scalar).
• UBOUND(SOURCE[,DIM])

  Returns a one dimensional array containing the upper bounds of an array or, if a dimension is specified, a scalar containing the upper bound in that dimension. For example,

  • UBOUND(A) is (/10,23,28/)
  • UBOUND(A,1) is 10.
• SHAPE(SOURCE)

  Returns a one dimensional array containing the shape of an object. For example,

  • SHAPE(A) is (/21,23,15/) (array);
  • SHAPE((/4/)) is (/1/) (array).
• SIZE(SOURCE[,DIM])

  Returns a scalar containing the total number of array elements either in the whole array or in an optionally specified dimension. For example,

  • SIZE(A,1) is 21.
  • SIZE(A) is 7245.
  • SIZE(4) is an error as the argument must not be scalar.
• ALLOCATED(SOURCE)

  Returns a scalar LOGICAL result indicating whether an array is allocated or not. For example,

      PROGRAM Main
       IMPLICIT NONE
        INTEGER, ALLOCATABLE, DIMENSION(:) :: Vec
         PRINT*, ALLOCATED(Vec)
         ALLOCATE(Vec(10))
         PRINT*, ALLOCATED(Vec)
         DEALLOCATE(Vec)
         PRINT*, ALLOCATED(Vec)
      END PROGRAM Main

  will produce .FALSE., .TRUE. and .FALSE. in that order.

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