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Add factors

Posted: Wed Apr 11, 2018 8:35 am
by Dag Kolsrud
I got the message: Overflow in "A31 equation" in "__KVARTSMODELLEN.ADDINIT(S=B, V=N) @ALL". What does it mean?

The A31 equation is "0*A31+... = ...+0.94748*A31+..." where the 0*A31 has been inserted on the left hand side of the equation (which was transported from a program system where the endogenous variable can be anywhere in the equation) in order to satisfy EViews requirement. That works fine for solving the model without add factors. Moving +0.94748*A31 from the right hand side to replace 0*A31 first on the left hand side removes the error message. Why?

Re: Add factors

Posted: Wed Apr 11, 2018 8:42 am
by EViews Gareth
Overflow is caused by the model generating a number that is too large for the computer to handle. Usually due to logs (or rather inverting the log to exponentials).

Re: Add factors

Posted: Wed Apr 11, 2018 8:45 am
by Dag Kolsrud
Why did the error message disappear when I rearranged the Equation as described in my first email?

Re: Add factors

Posted: Wed Apr 11, 2018 9:00 am
by EViews Gareth
Hard to say.

Re: Add factors

Posted: Wed Apr 11, 2018 9:29 am
by tvonbrasch
Hi Gareth

When moving our macro model from TROLL to EViews we have to make EViews understand which variable that is to be treated as endogenous in each equation. For example, if we have the equation
y = 4*x + .2*y

and x is to be treated as the endogenous variable, EViews Chris reccommended that we just rewrite the equation as
0*x + y = 4*x + .2*y

see the post http://forums.eviews.com/viewtopic.php? ... oll#p33688.

Now it seems that this advice creates some problems with respect to initializations of add factors. To see this, run the commands

Code: Select all

wfcreate u 100 genr x=50+0.03*@trend+2*nrnd genr log(y)=3*log(x)+nrnd model _m _m.append 0*x+log(y)=3*log(x) '_m.replace 3*log(x)=log(y) _m.addassign(v) @all _m.addinit(v=n) @all
Which generates the error message:
Overflow in "X equation" in "_M.ADDINIT(V=N) @ALL".
If you however uncomment the line '_m.replace 3*log(x)=log(y), the addinit command works fine. This is what Dag illustrated in the example above. Is this something you can fix? If so, it would be highly appreciated.
Thomas

Re: Add factors

Posted: Wed Apr 11, 2018 10:16 am
by EViews Gareth
I just ran that program 1,000 times and it didn't generate an error once...

Re: Add factors

Posted: Wed Apr 11, 2018 11:43 am
by tvonbrasch
What kind of superpowers do you have?

The first picture is the error I get when running the program. I get the second error when I have the model

Code: Select all

_m.append x+log(y)=3*log(x)+x
i.e., I change y=f(x) to x+y=f(x)+x, instead of 0*x+y=f(x).

I have EViews 10, Apr 3. 2018.

It is very strange that you cannot reproduce this... I have also attached a workfile. Try to run the command

Code: Select all

_m.addinit(v=n) @all
and you should get the error message in the second picture.
Thomas
Error1.PNG
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Error2.PNG
Error2.PNG (17.75 KiB) Viewed 22437 times

Re: Add factors

Posted: Wed Apr 11, 2018 12:40 pm
by EViews Gareth
Yes, I get the error message on the posted workfile, but if I changed the models specification to:

Code: Select all

0*x + log(y) = 3*log(x)
the error goes away.

Re: Add factors

Posted: Wed Apr 11, 2018 12:53 pm
by tvonbrasch
that is strange,

do you get an error if you run the command

Code: Select all

_m.addinit(v=n) @all
on the attached workfile? In this case the model is: 0 * x + log(y) = 3 * log(x).

When I run it, I get:
1.PNG
1.PNG (41.49 KiB) Viewed 22432 times
Thomas

Re: Add factors

Posted: Wed Apr 11, 2018 1:08 pm
by EViews Gareth
No error.

Try deleting (or moving so you can move it back) your EViews ini file.

Re: Add factors

Posted: Wed Apr 11, 2018 9:44 pm
by tvonbrasch
I moved the ini file and reopened EViews (EViews then created another ini file), but EViews still reports an error when running the program......

any other ideas about what is causing this error?
T
error_after_ini.PNG
error_after_ini.PNG (45.23 KiB) Viewed 22417 times