11 a.m.
Is there any way to update variables that are functions of another, if the
original variable Y has been amended or updated . The former is
straightforward to edit Y's values. But I am not clear that for example,
l-Y is automatically recalculated. And if l-Y has already been used in a
session, Gretl will not let it be deleted giving the error message cannot
be deleted variable in use..
Suggestions around this issue welcomed
Brian J Revell
Professor Emeritus
Agricultural and Food Economics
Harper Adams University
Newport
Shropshire TF10 8NB
Tel 01952 815237
Tel: +44 1952 728153
Mbl +44 7976 538712
University: +44 1952 815235
alt: email: bjrevell(a)harper-adams.ac.uk
12:07 p.m.
Am 23.12.20 um 12:00 schrieb Brian Revell:
Is there any way to update variables that are functions of another,
if
the original variable Y has been amended or updated . The former is
straightforward to edit Y's values. But I am not clear that for
example, l-Y is automatically recalculated. And if l-Y has already
been used in a session, Gretl will not let it be deleted giving the
error message cannot be deleted variable in use..
Suggestions around this issue welcomed
Hi Brian,
Nothing gets automatically re-computed -- which is good. If you want to
re-compute anything, you should make use of a function which needs to be
called each time you have new/ different input variables. See the
following example.
With rehard to your second point: Could you give an example please?
<hansl>
scalar X = 4
scalar Y = 3
scalar Z = X - Y
print X Y Z
# changes in Y do not affect previously assigned Z
scalar Y = 2
print X Y Z
# Make use of a function for 'updating' Z
function scalar compute_z (scalar X, scalar Y)
return X - Y
end function
scalar Y = 3
eval compute_z(X, Y)
scalar Y = 2
eval compute_z(X, Y)
</hansl>
Artur
12:33 p.m.
Am 23.12.2020 um 13:07 schrieb Artur Tarassow:
Am 23.12.20 um 12:00 schrieb Brian Revell:
> Is there any way to update variables that are functions of another,
> if the original variable Y has been amended or updated . The former
> is straightforward to edit Y's values. But I am not clear that for
> example, l-Y is automatically recalculated. And if l-Y has already
> been used in a session, Gretl will not let it be deleted giving the
> error message cannot be deleted variable in use..
> Suggestions around this issue welcomed
Hi Brian,
Nothing gets automatically re-computed -- which is good. If you want
to re-compute anything, you should make use of a function which needs
to be called each time you have new/ different input variables.
Perhaps it should be added that it is not necessary to write a formal
function. For example there's the command log that automatically records
everything (well, almost) you did in a gretl session. See Tools/Command
log. That is basically a script you could replay (or parts of it
probably) again to update the construction.
cheers
sven
2:02 p.m.
'Artur
perhaps I was not clear. Sometimes observations on say Y may be updated or
revised. That means after I change those in Gretl any transformation such
as ln Y or difference Y that I may have created before the update will
still use the original Y data as they do not update automatically. When I
try to delete these variables, because they have been used in the session,
Gretl will not allow me delete them in order to re-create them using the
updated Y.
I have figured a workaround which is to define a variable YNEW=Y and then
create the transforms needed using YNew. But that is not very elegant!
Brian
On Wed, 23 Dec 2020 at 12:07, Artur Tarassow <atecon(a)posteo.de> wrote:
Am 23.12.20 um 12:00 schrieb Brian Revell:
> Is there any way to update variables that are functions of another, if
> the original variable Y has been amended or updated . The former is
> straightforward to edit Y's values. But I am not clear that for
> example, l-Y is automatically recalculated. And if l-Y has already
> been used in a session, Gretl will not let it be deleted giving the
> error message cannot be deleted variable in use..
> Suggestions around this issue welcomed
Hi Brian,
Nothing gets automatically re-computed -- which is good. If you want to
re-compute anything, you should make use of a function which needs to be
called each time you have new/ different input variables. See the
following example.
With rehard to your second point: Could you give an example please?
<hansl>
scalar X = 4
scalar Y = 3
scalar Z = X - Y
print X Y Z
# changes in Y do not affect previously assigned Z
scalar Y = 2
print X Y Z
# Make use of a function for 'updating' Z
function scalar compute_z (scalar X, scalar Y)
return X - Y
end function
scalar Y = 3
eval compute_z(X, Y)
scalar Y = 2
eval compute_z(X, Y)
</hansl>
Artur
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2:47 p.m.
Am 23.12.2020 um 15:02 schrieb Brian Revell:
'Artur
perhaps I was not clear. Sometimes observations on say Y may be
updated or revised. That means after I change those in Gretl any
transformation such as ln Y or difference Y that I may have created
before the update will still use the original Y data as they do not
update automatically. When I try to delete these variables, because
they have been used in the session, Gretl will not allow me delete
them in order to re-create them using the updated Y.
I have figured a workaround which is to define a variable YNEW=Y and
then create the transforms needed using YNew. But that is not very
elegant!
Brian
Yes you cannot delete them, but re-assigning new values to the existing
series should work without problems. If you're working with different
samples and are afraid of mixing up stuff by accident you could perhaps
set all values to missing first. Or you could close and re-open the
dataset which should get rid of the "in use" problem.
-s
1471
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1471
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4 comments
3 participants
participants (3)
-
Artur Tarassow -
Brian Revell -
Sven Schreiber