Intel Fortran Language Reference - NCI National Facility

3 Intel Fortran Language Reference
An array has the following properties:
• Data type
An array can have any intrinsic or derived type. The data type of an array (like any other
variable) is specified in a type declaration statement or implied by the first letter of its name.
All elements of the array have the same type and kind parameters. If a value assigned to an
individual array element is not the same as the type of the array, it is converted to the array's
type.
• Rank
The rank of an array is the number of dimensions in the array. An array can have up to seven
dimensions. A rank-one array represents a column of data (a vector), a rank-two array
represents a table of data arranged in columns and rows (a matrix), a rank-three array
represents a table of data on multiple pages (or planes), and so forth.
• Bounds
Arrays have a lower and upper bound in each dimension. These bounds determine the range
of values that can be used as subscripts for the dimension. The value of either bound can be
positive, negative, or zero.
The bounds of a dimension are defined in an array specification.
• Size
The size of an array is the total number of elements in the array (the product of the array's
extents).
The extent is the total number of elements in a particular dimension. It is determined as
follows: upper bound – lower bound + 1. If the value of any of an array's extents is zero, the
array has a size of zero.
• Shape
The shape of an array is determined by its rank and extents, and can be represented as a
rank-one array (vector) where each element is the extent of the corresponding dimension.
Two arrays with the same shape are said to be conformable. A scalar is conformable to an
array of any shape.
The name and rank of an array must be specified when the array is declared. The extent of each
dimension can be constant, but does not need to be. The extents can vary during program
execution if the array is a dummy argument array, an automatic array, an array pointer, or an
allocatable array.
A whole array is referenced by the array name. Individual elements in a named array are
referenced by a scalar subscript or list of scalar subscripts (if there is more than one dimension). A
section of a named array is referenced by a section subscript.
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