求GAMS大神帮我看一下如下文献中看到的代码为啥在软件里跑不出来、持续报错。
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Simple Spatial Equilibrium Example
Primal or quantity formulation.
Erwin Kalvelagen, nov 2001
Data from:
Takayama and Judge,
Spatial and temporal price and allocation models
North Holland, 1971

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set i ’regions’ /region1,region2,region3/;
alias (i,j);
positive variables
d(j) ’demand’
s(i) ’supply’
pd(j) ’price (demand)’
ps(i) ’price (supply)’
x(i,j) ’shipments’
;
free variable
welfare ’quasi welfare’
;
equations
excess_demand(j) ’no excess demand allowed’
excess_supply(i) ’excess supply is possible’
objective ’net quasi welfare function’
price_demand(j) ’demand curve (inverse)’
price_supply(i) ’supply curve (inverse)’
;
table data(i,*,*) ’data for inverse demand and supply equations’
intercept slope
region1.demand 20 -0.1
region1.supply 5 0.1
region2.demand 20 -0.2
region2.supply 2.5 0.05
region3.demand 20 -0.125
region3.supply 5 0.1
;
table c(i,j) ’transportation costs’
region1 region2 region3
region1 2 2
region2 2 1
region3 2 1
;
parameters zeta(j),eta(j),theta(i),lambda(i);
zeta(j) = data(j,’demand’,’intercept’);
eta(j) = data(j,’demand’,’slope’);
theta(i) = data(i,’supply’,’intercept’);
lambda(i) = data(i,’supply’,’slope’);
price_demand(j).. pd(j) =e= zeta(j)+eta(j)*d(j);
price_supply(i).. ps(i) =e= theta(i)+lambda(i)*s(i);
objective.. welfare =e=
sum(j,zeta(j)*d(j)+0.5*eta(j)*sqr(d(j)))
-sum(i,theta(i)*s(i)+0.5*lambda(i)*sqr(s(i)))
-sum((i,j), c(i,j)*x(i,j));
excess_demand(j).. sum(i, x(i,j)) =g= d(j);
excess_supply(i).. sum(j, x(i,j)) =l= s(i);

model m /objective,excess_demand,excess_supply,price_demand,price_supply/;
solve m using nlp maximizing welfare;



感谢