DIMENSIONS.html -- ACL2 Version 6.3

### DIMENSIONS

return the `:dimensions` from the header of a 1- or 2-dimensional array

    Major Section:  ARRAYS

    Example Form:
    (dimensions 'delta1 a)

    General Form:
    (dimensions name alist)

where `name` is arbitrary and `alist` is a 1- or 2-dimensional array. This function returns the dimensions list of the array `alist`. That list will either be of the form `(dim1)` or `(dim1 dim2)`, depending on whether `alist` is a 1- or 2-dimensional array. `Dim1` and `dim2` will be integers and each exceed by 1 the maximum legal corresponding index. Thus, if `dimensions` returns, say, `'(100)` for an array `a` named `'delta1`, then `(aref1 'delta1 a 99)` is legal but `(aref1 'delta1 a 100)` violates the guards on `aref1`. `Dimensions` operates in virtually constant time if `alist` is the semantic value of `name`. See arrays.