Error 492 Symbol not in GDX

GAMS
1

Hi! I´m trying to import data from excel to GAMS.

Sets
t “Zeit” /1*200



Parameters
x (t)
y (t)
z (t)


$onecho>gdxxrw Data-x-y-z.xlsx
set=t rng=Tabelle5!E2:E201 cdim=0 rdim=1
par=x rng=Tabelle5!A2:A201 cdim=0 rdim=1
par=y rng=Tabelle5!B2:B201 cdim=0 rdim=1
par=z rng=Tabelle5!C2:C201 cdim=0 rdim=1

$offecho
$call GDXXRW Data-x-y-z.xlsx
$GDXIN Data-x-y-z.gdx
$LOAD t, x, y, z
$gdxIn


But then error 492 “Symbol not in GDX” appears.
It just creates an empty GDX file.


I would be very thankful for any advices.

2

Hi,

Study the documentation of gdxxrw and how to use a gdxxrw option/parameteri file. You seem to have destroyed your xlsx workbook with your command sequence. What you probably want to do is:

$onecho> Data-x-y-z.txt
input = Data-x-y-z.xlsx
set=t rng=Tabelle5!E2:E201 cdim=0 rdim=1
par=x rng=Tabelle5!A2:A201 cdim=0 rdim=1
par=y rng=Tabelle5!B2:B201 cdim=0 rdim=1
par=z rng=Tabelle5!C2:C201 cdim=0 rdim=1
$offecho
$call.checkErrorLevel GDXXRW @Data-x-y-z.txt
$GDXIN Data-x-y-z.gdx
$LOAD t, x, y, z
$gdxIn

Always check the return code of external program ($call.checkErrorLevel ) in case things go bad.

-Michael

PS phpBB has a nice code section, use it!

3

Thanks for your reply! I’m new in the world of GAMS so it gets sometimes a bit hard for me. I guess my problem with creating a GDX is the error “there were at least 10 duplicate entries for symbol x”. Is there an option to solve this?
Thank you really much for you help.

4

No, GAMS does not allow duplicate records. If you post the spreadsheet and what you want to read into GAMS then we might be able to help better.

-Michael

5

Hi!
In the following I show you the code I used and my Excel sheet as an attachment.

Sets
t “time” /1*51/

Parameters
X(t) Price for x at time t
Y(t) Price for Y at time t
Z(t) Price for Z at time t;

$onecho>input_data2.txt

par=X rng=priceX!B2:B51 cdim=0 rdim=1
par=Y rng=priceY!B2:B51 cdim=0 rdim=1
par=Z rng=priceZ!B2:B51 cdim=0 rdim=1
$offecho
$call GDXXRW input_data2.xlsx @input_data2.txt
$GDXIN input_data2.gdx
$LOAD X,Y,Z
$gdxIn

Now it creates an empty gxx data. Before that i had the error that duplicates are not possible.

I´m very thankful for any advice!

Best Greetings
TheBebbo
input_data3.xlsx (570 KB)

6

Hi,
the index is part of the range you are reading. So start reading at A2 instead of B2

par=X rng=priceX!A2:B51 cdim=0 rdim=1
par=Y rng=priceY!A2:B51 cdim=0 rdim=1
par=Z rng=priceZ!A2:B51 cdim=0 rdim=1

Also note that the excel file name doe snot fit with your example code.
I hope this helps!

Fred

7

Thanks for your reply! I only changed the name of the excel sheet to post it here. So When I tried it it fit to the code.

I changed the range to A2:B51 but it still creates only an empty GDX file.

8

You are right. This is because you define t as 1,2,…,51 in your code but in your data you use t1, t2, …, t51. By default, GAMS does a filtered load meaning that zero records are loaded. The following should work.

Sets
t "time" /t1*t51/

Parameters
X(t) Price for x at time t
Y(t) Price for Y at time t
Z(t) Price for Z at time t;

$onecho>input_data2.txt

par=X rng=priceX!A2:B51 cdim=0 rdim=1
par=Y rng=priceY!A2:B51 cdim=0 rdim=1
par=Z rng=priceZ!A2:B51 cdim=0 rdim=1

$offecho
$call.checkErrorLevel  GDXXRW input_data3.xlsx @input_data2.txt trace=3
$GDXIN input_data3.gdx
$LOAD X,Y,Z
$gdxIn

display X, Y, Z;
9

It works! Thank you so much! You helped me a lot :slight_smile: