HasImplicitDimension
New to Analytica 6.0
HasImplicitDimension(x)
Returns true when «x» is an array with an implicit dimension.
An implicit dimension is a dimension that is not associated with an index object. A list is the most basic example, which is a one-dimensional array with no associated index. The single dimension cannot be explicitly identified by name. When a list is combined with an array value, the resulting array has the indexes of the original array plus one additional implicit dimension.
This will return true for pseudo-dimensions as well. This concept is illustrated in the following example:
- LocalIndex J := 1..3; /* This is a real index */
- [[Local] a := 1..5; /* This is NOT an index. But it is a pseudo-index */
- Local x := a^J; /* A 2-D array */
- HasImplicitDimension(x) /* return true */
In the example, the local a
is a value and is not an index, but since it was assigned a list value, it has an implicit dimension, which is also an implicit dimension in x
. But while the local a
remains in lexical scope, there is a way of referring to that dimension by name, i.e., it would work to write Sum(x,a)
. However, once local a
falls out of scope, it will no longer be possible to refer to that dimension by name, and hence, it is implicit. In contrast, when J
leaves lexical scope, you would still be able to refer to its index using x.J
, hence J
is an explicit index.
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