## Monday, July 28, 2008

### GDX question

> I would like to make a gdx dump of all the sets/paramters/scalars of
> my model, but I do not want any equations or variables in there at
> all.

``\$version 227   Sets       i   canning plants   / seattle, san-diego /       j   markets          / new-york, chicago, topeka / ;   Parameters        a(i)  capacity of plant i in cases         /    seattle     350              san-diego   600  /        b(j)  demand at market j in cases         /    new-york    325              chicago     300              topeka      275  / ;   Table d(i,j)  distance in thousands of miles                    new-york       chicago      topeka      seattle          2.5           1.7          1.8      san-diego        2.5           1.8          1.4  ;   Scalar f  freight in dollars per case per thousand miles  /90/ ;   Parameter c(i,j)  transport cost in thousands of dollars per case ;             c(i,j) = f * d(i,j) / 1000 ;   Variables       x(i,j)  shipment quantities in cases       z       total transportation costs in thousands of dollars ;   Positive Variable x ;   Equations       cost        define objective function       supply(i)   observe supply limit at plant i       demand(j)   satisfy demand at market j ;   cost ..        z  =e=  sum((i,j), c(i,j)*x(i,j)) ;   supply(i) ..   sum(j, x(i,j))  =l=  a(i) ;   demand(j) ..   sum(i, x(i,j))  =g=  b(j) ;   Model transport /all/ ;   Solve transport using lp minimizing z ;   Display x.l, x.m ;  * generate include file execute_unload statement* that write all symbols except variables and* equations\$onecho > f.awkBEGIN {print "execute_unload 'mygdx'" > "temp1.inc"}/^ *[0-9]+ / {  if (\$4=="Equ") next;  if (\$4=="Var") next;  print "," \$2 > "temp1.inc"}END {print ";" > "temp1.inc"}\$offecho\$gdxout temp1\$unload\$gdxout\$call 'gdxdump temp1 symbols > temp1.txt'\$call 'awk -f f.awk temp1.txt'\$include temp1.inc * mygdx.gdx will not contain any variables or equationsexecute 'gdxdump mygdx symbols';``

Basically at compile time we dump a gdx file temp1.gdx that has all symbols. Then we use an AWK scripts (still at GAMS compile time) to generate an include file temp1.inc that contains an execute_unload statement with all non var/equ symbols to mygdx.gdx. Then we \$include this file. Finally for checking we call gdxdump (at execution time) to show all symbols in mygdx.gdx.