Array

An array type.

Declaration

Syntax

Array(ttype type, dimension* dims, array_physical_type physical_type,
    memory_space memory_space)

Arguments

Argument

Описание

type

the element type. It is never itself an array: a rank two array is one Array with two dimensions.

dims

one dimension per rank, giving the lower bound and the extent. Both may be nil when the shape is not known where the type is written.

physical_type

how the array is represented; see array_physical_type.

memory_space

which memory the storage lives in; see memory_space.

Return values

None. A type is not evaluated.

Описание

The shape is part of the type, so a procedure’s dummy argument and the actual argument passed to it may have the same element type and rank but different physical_type, and the frontend inserts an ArrayPhysicalCast between them.

The physical type has to agree with the dimensions, and the verifier checks that it does:

  • a FixedSizeArray is stored inline, so every lower bound and every extent is a compile-time constant (asr.verify.array.fixed_size_constant_dims). The deferred constants of a template are exempt until it is instantiated;

  • an allocatable or pointer array is a DescriptorArray (asr.verify.allocatable.array_descriptor, asr.verify.pointer.array_descriptor);

  • an assumed-size dummy argument, a(n, *), is passed as its data alone and has no extent in its last dimension, so it is never a DescriptorArray unless it is polymorphic and the descriptor carries its dynamic type (asr.verify.variable.assumed_size_descriptor). It is an UnboundedPointerArray, or a PointerArray for bind(c). A rank one a(*) has the same dimensions as the assumed-shape a(:), so only the physical type tells the two apart.

An assumed-rank array has no dimensions at all: its dims is empty and its physical type is AssumedRankArray. Its rank is only known at the call, and SelectRank is what recovers it.

memory_space says which memory the elements live in. Everything on the host is Global, and so is a buffer a kernel is given; the other spaces appear only inside GPU code, where a variable may instead be private to a thread or shared by a threadgroup. See memory_space.

Examples

(Array
  :type (Integer
    :kind 4
  )
  :dims [
    (dimension
      :start (IntegerConstant
        :n 1
        :type (Integer
          :kind 4
        )
        :intboz_type :Decimal
      )
      :length (IntegerConstant
        :n 3
        :type (Integer
          :kind 4
        )
        :intboz_type :Decimal
      )
    )
  ]
  :physical_type :FixedSizeArray
  :memory_space :Global
)

It comes from this complete ASR text document:

(TranslationUnit
  :symtab (SymbolTable
    :id 0
    :symbols {
      "main" (Program
        :symtab (SymbolTable
          :id 1
          :symbols {
            "a" (Variable
              :parent_symtab 1
              :name "a"
              :dependencies []
              :intent :Local
              :symbolic_value nil
              :value nil
              :storage :Default
              :type (Array
                :type (Integer
                  :kind 4
                )
                :dims [
                  (dimension
                    :start (IntegerConstant
                      :n 1
                      :type (Integer
                        :kind 4
                      )
                      :intboz_type :Decimal
                    )
                    :length (IntegerConstant
                      :n 3
                      :type (Integer
                        :kind 4
                      )
                      :intboz_type :Decimal
                    )
                  )
                ]
                :physical_type :FixedSizeArray
                :memory_space :Global
              )
              :type_declaration nil
              :abi :Source
              :access :Public
              :presence :Required
              :value_attr false
              :target_attr false
              :contiguous_attr false
              :bindc_name nil
              :is_volatile false
              :is_protected false
              :pass_attr :NotMethod
              :self_argument nil
              :codims []
              :common_block nil
            )
            "b" (Variable
              :parent_symtab 1
              :name "b"
              :dependencies []
              :intent :Local
              :symbolic_value nil
              :value nil
              :storage :Default
              :type (Array
                :type (Integer
                  :kind 4
                )
                :dims [
                  (dimension
                    :start (IntegerConstant
                      :n 1
                      :type (Integer
                        :kind 4
                      )
                      :intboz_type :Decimal
                    )
                    :length (IntegerConstant
                      :n 3
                      :type (Integer
                        :kind 4
                      )
                      :intboz_type :Decimal
                    )
                  )
                ]
                :physical_type :FixedSizeArray
                :memory_space :Global
              )
              :type_declaration nil
              :abi :Source
              :access :Public
              :presence :Required
              :value_attr false
              :target_attr false
              :contiguous_attr false
              :bindc_name nil
              :is_volatile false
              :is_protected false
              :pass_attr :NotMethod
              :self_argument nil
              :codims []
              :common_block nil
            )
            "i" (Variable
              :parent_symtab 1
              :name "i"
              :dependencies []
              :intent :Local
              :symbolic_value nil
              :value nil
              :storage :Default
              :type (Integer
                :kind 4
              )
              :type_declaration nil
              :abi :Source
              :access :Public
              :presence :Required
              :value_attr false
              :target_attr false
              :contiguous_attr false
              :bindc_name nil
              :is_volatile false
              :is_protected false
              :pass_attr :NotMethod
              :self_argument nil
              :codims []
              :common_block nil
            )
            "l" (Variable
              :parent_symtab 1
              :name "l"
              :dependencies []
              :intent :Local
              :symbolic_value nil
              :value nil
              :storage :Default
              :type (Logical
                :kind 4
              )
              :type_declaration nil
              :abi :Source
              :access :Public
              :presence :Required
              :value_attr false
              :target_attr false
              :contiguous_attr false
              :bindc_name nil
              :is_volatile false
              :is_protected false
              :pass_attr :NotMethod
              :self_argument nil
              :codims []
              :common_block nil
            )
          }
        )
        :name "main"
        :dependencies []
        :body [
          (Assignment
            :target (Var
              :v (SymbolRef 1 "a")
            )
            :value (ArrayConstant
              :n_data 12
              :data #asr/bytes "010000000200000003000000"
              :type (Array
                :type (Integer
                  :kind 4
                )
                :dims [
                  (dimension
                    :start (IntegerConstant
                      :n 1
                      :type (Integer
                        :kind 4
                      )
                      :intboz_type :Decimal
                    )
                    :length (IntegerConstant
                      :n 3
                      :type (Integer
                        :kind 4
                      )
                      :intboz_type :Decimal
                    )
                  )
                ]
                :physical_type :FixedSizeArray
                :memory_space :Global
              )
              :storage_format :ColMajor
            )
            :overloaded nil
            :realloc_lhs false
            :move_allocation false
            :new_target false
          )
          (Assignment
            :target (Var
              :v (SymbolRef 1 "i")
            )
            :value (ArrayItem
              :v (Var
                :v (SymbolRef 1 "a")
              )
              :args [
                (array_index
                  :left nil
                  :right (IntegerConstant
                    :n 2
                    :type (Integer
                      :kind 4
                    )
                    :intboz_type :Decimal
                  )
                  :step nil
                )
              ]
              :type (Integer
                :kind 4
              )
              :storage_format :ColMajor
              :value nil
              :in_bounds false
            )
            :overloaded nil
            :realloc_lhs false
            :move_allocation false
            :new_target false
          )
          (Assignment
            :target (Var
              :v (SymbolRef 1 "b")
            )
            :value (ArraySection
              :v (Var
                :v (SymbolRef 1 "a")
              )
              :args [
                (array_index
                  :left (IntegerConstant
                    :n 1
                    :type (Integer
                      :kind 4
                    )
                    :intboz_type :Decimal
                  )
                  :right (IntegerConstant
                    :n 3
                    :type (Integer
                      :kind 4
                    )
                    :intboz_type :Decimal
                  )
                  :step (IntegerConstant
                    :n 1
                    :type (Integer
                      :kind 4
                    )
                    :intboz_type :Decimal
                  )
                )
              ]
              :type (Array
                :type (Integer
                  :kind 4
                )
                :dims [
                  (dimension
                    :start (IntegerConstant
                      :n 1
                      :type (Integer
                        :kind 4
                      )
                      :intboz_type :Decimal
                    )
                    :length (IntegerConstant
                      :n 3
                      :type (Integer
                        :kind 4
                      )
                      :intboz_type :Decimal
                    )
                  )
                ]
                :physical_type :DescriptorArray
                :memory_space :Global
              )
              :value nil
            )
            :overloaded nil
            :realloc_lhs false
            :move_allocation false
            :new_target false
          )
          (Assignment
            :target (Var
              :v (SymbolRef 1 "i")
            )
            :value (ArraySize
              :v (Var
                :v (SymbolRef 1 "a")
              )
              :dim (IntegerConstant
                :n 1
                :type (Integer
                  :kind 4
                )
                :intboz_type :Decimal
              )
              :type (Integer
                :kind 4
              )
              :value nil
            )
            :overloaded nil
            :realloc_lhs false
            :move_allocation false
            :new_target false
          )
          (Assignment
            :target (Var
              :v (SymbolRef 1 "i")
            )
            :value (ArrayRank
              :v (Var
                :v (SymbolRef 1 "a")
              )
              :type (Integer
                :kind 4
              )
              :value nil
            )
            :overloaded nil
            :realloc_lhs false
            :move_allocation false
            :new_target false
          )
          (Assignment
            :target (Var
              :v (SymbolRef 1 "i")
            )
            :value (ArrayBound
              :v (Var
                :v (SymbolRef 1 "a")
              )
              :dim (IntegerConstant
                :n 1
                :type (Integer
                  :kind 4
                )
                :intboz_type :Decimal
              )
              :type (Integer
                :kind 4
              )
              :bound :UBound
              :value nil
            )
            :overloaded nil
            :realloc_lhs false
            :move_allocation false
            :new_target false
          )
          (Assignment
            :target (Var
              :v (SymbolRef 1 "l")
            )
            :value (ArrayIsContiguous
              :array (Var
                :v (SymbolRef 1 "a")
              )
              :type (Logical
                :kind 4
              )
              :value nil
            )
            :overloaded nil
            :realloc_lhs false
            :move_allocation false
            :new_target false
          )
        ]
        :global_init nil
      )
    }
  )
  :items []
  :global_init nil
)

See Also

dimension, array_physical_type, memory_space, ArrayItem, ArrayPhysicalCast, ArrayConstant