[Gretl-users] vertical matrix concatenation (was matrix
declaration error)
Allin Cottrell
cottrell at wfu.edu
Wed Jan 31 09:52:48 EST 2007
Me:
>> The main problem I see is identifying a "matrix-generating
>> expression" for the purpose of interpreting "|". My notion is
>> that this would be the right-hand side of a "matrix M = ..."
>> command, or the right-hand side of commands on the pattern
>>
>> genr M = ...
>> M = ...
>>
>> where "M" can be identified as a pre-existing matrix.
Sven:
> Has the syntax changed here? I thought the 'matrix' keyword
> always has to precede matrix-related statements?
Yes, it has changed.
Gretl now has "static typing". This means that once a given
variable is defined as having a certain type, you can't change
its type on the fly. For example, this will produce an error:
scalar x = 2
x = log(price)
if "price" is a series. On the other hand it is OK to "cast" a
variable to a different type, as in
scalar x = 2
series y = x
which produces a series each of whose observations has value 2.
One advantage of static typing is that you don't have to keep
repeating type identifiers such as "matrix": if M is initially
defined as a matrix, you can thereafter use plain "M" on the
left-hand side of genr-type commands: gretl will know that it's
supposed to be generating a matrix.
Allin.
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