GAMS models (transportation, thrift, general equilibrium)
JQuiz Instructions
The transportation model seeks to determine...
the prices of the goods to be sent to markets.
the supply that can be provided by some plants.
the quantities to be shipped from plants to markets.
the 2-dim locations of plants.
The transportation model has constraints...
related to physical distance between a plan and a market.
relative to capacities and to demands.
that limits the maximum amount that can be shipped.
that involves the distance between some towns.
Which of the following sentences are true for the transportation model?
The transportation model is a linear model because:
The objective function is linear.
The constraints are linear.
The shipment cost depends linearly on the distance.
The objective function and the constraints are linear.
Immagine to reduce tha capacity of the plants in a transportation model, leaving the other parameters unchanged.
GAMS always finds a solution and writes in the .lst file
"SOLVER STATUS 1 NORMAL COMPLETION"
GAMS always finds a solution and writes in the .lst file
"MODEL STATUS 1 OPTIMAL"
GAMS may fail to find a solution. The .lst file reads
"SOLVER STATUS 1 NORMAL COMPLETION" "MODEL STATUS 4 INFEASIBLE"
Given the shortage, GAMS reports in the .lst file
"MODEL STATUS 3 UNBOUNDED"
The following output by GAMS
**** SOLVER STATUS 1 Normal Completion **** MODEL STATUS 4 Infeasible **** OBJECTIVE VALUE 171.8100 RESOURCE USAGE, LIMIT 0.009 1000.000 ITERATION COUNT, LIMIT 1 2000000000
In the transportation model, recall that two sets were defined as SETS I canning plants / SEATTLE, SAN-DIEGO / J markets / NEW-YORK, CHICAGO, TOPEKA / ;
Whats the meaning of SUM(J, X(I,J)) =L= A(I) ; ?
It is used to define a capacity constraint.
It is used to define a demand constraint.
It is used to define the objective function as a sum of costs.
It is used to display the levels of X(I,J).
The output
---- 66 VARIABLE X.L shipment quantities in cases
NEW-YORK CHICAGO TOPEKA
SEATTLE 125.000 225.000 SAN-DIEGO 375.000 225.000
shows the lower limits of shipment variables X.
shows the upper limits of variables X.
shows the levels, i.e. the values, of shipment variables X.
was produced by a MODEL statement and defines the model X.
To write the costraint x≥3 using GAMS, you type:
x > 3;
x =e= 3;
x =g= 3;
x ≥ 3;
In GAMS, the statements sqr(x) and sqrt(x)...
The linear system made of the two equations x + y = 2 and x- y = 2...
The solution of a linear system is involved...
in the transportation model.
in the maximimization of consumptions in the Ramsey model.
in the Leontief input-output model.
in the the thrift model.
What's the typical structure of a GAMS program?
Sets, Variables, Equations and Constraints, Model, Solve.
Modify (only) the initial bond endowment to 3000 $ in the standard thrift model. What's the student loan debt in 2003? (You may need to renormalize amounts and edit the file.)
1991.238
10549
9372
12115
Modify (only) the checking account to 3000 $ in the standard thrift model. What's the credit card debt in 2004? (You may need to renormalize amounts and edit the file.)
2096
2085
1992
1975
Which of the following GAMS sentence would generate an error?
In the thrift model, we...
In an input-output model...
quantities produced are determined given technology and exogenouos demand.
technology coefficients are determined given quantities and demand.
prices are determined given technology and demand.
internal demand is determined given quantities and prices.
A Leontief input-output model can be solved...
finding the solutions of a linear system.
maximizing the demand of one good in the economy.
minimizing the cost of production in the economy.
equalling the sum of the productions to a predetermined capacity.
An input-output model can be written as...
The equation v + Pi + w = p, where v = costs of inputs, Pi is profit, w = wage and p stands for price, is...
In a production prices model...
we maximize profits.
we maximize wages.
we minimize the cost of inputs.
we do not maximize or minimize at all.
Using a deflator for the wage means...
that we multiply the wage by the hours worked.
that we divide the wage by the hours worked to get a unit wage.
that we divide the wage by the price of one of the goods of the economy.
that we sum to the wage the value of goods to compute the real wage.
Which of the following GAMS statements correctly define the constraint x ≤ 14 ?