[AMPL 2579] Problem in using let command

Hi all,

I have a decompositin problem to solve. In my .run file, there are
"let" commands, assigning initial values to variables defined in .mod
file. But, the problem occurs as solver (cplexamp) does not take these
initial values into account during its first run. Could somebody help
and explain what it could be wrong?

This is part of .run file with just a master problem.

model proba.mod;
data proba.dat;

option solver cplexamp;
option cplex_options 'mipdisplay 2 mipinterval 100 primal';
option cplex_option 'timelimit=900';

option omit_zero_rows 1;
option display_eps .000001;

problem Master: x2, Ship_pro, Y121, xcon1, xcon2, xcon3, xcon4;
Cut_Point, Cut_Ray;

let Ship_pro := 10000000;

param GAP default Infinity;

printf "\nRE-SOLVING MASTER PROBLEM\n\n";
solve Master;
printf "\n";

And this is part of .mod file with also just a Master problem.

param n>0, integer;

##sets
set Luke := 1..n;
set Luke1 within Luke := 1..n-1;
set Luke2 within Luke := 2..n;
set Luke3 within Luke := 2..n-1;

param pec{Luke};          #pec-lucke takse

var x2{Luke,Luke} binary;
var Ship_pro;

maximize Y121: 100000 - sum{i in Luke, j in Luke}x2[i,j]*pec[j];

subject to

Cut_Point {k in 1..nCUT}:
   if cut_type[k] = "point" then ZZ <= -sum{i in Luke1,j in Luke: j>=i
+1}alfa1[i,j,k]*zr[i,j]*sum{q in i+1..j}x2[i,q]
      -sum{i in Luke2,j in Luke: j<=i-1}beta1[i,j,k]*zr[i,j]*sum{q in
j..i-1}x2[i,q]
      -sum{i in Luke1,j in Luke: j>=i+1}xx1[i,j,k]*zr[i,j]*sum{q in
i..j-1}x2[q,j]
      -sum{i in Luke2,j in Luke: j<=i-1}delta1[i,j,k]*zr[i,j]*sum{q in
j+1..i}x2[q,j]
      +sum{i in 1..n-1,j in i+1..n: j!=i} fi1[i,j,k]*(C+MRS*(1-x2
[i,j]))
      +sum{i in 2..n,j in 1..i-1: j!=i} roi1[i,j,k]*(C+MRS*(1-x2
[i,j]))
      +tau1*(24*maxtt-sum{i in Luke,j in Luke:i!=j}x2[i,j]*(pdt[i]+pat
[j])-(l/v1+l/v2+tl+tb))
      +mi1*(24*mintt-sum{i in Luke,j in Luke:i!=j}x2[i,j]*(pdt[i]+pat
[j])-(l/v1+l/v2+tl+tb))
      +sum{i in Luke}lam1[i,k]*MRS+sum{i in Luke}rog1[i,k]*MRS;
      -(dcc*maxtt+Pout*(l/v1+l/v2)*(scf*fp+scl*lp))-sum{i in Luke, j
in Luke}x2[i,j]*pec[j];

Cut_Ray {k in 1..nCUT}:
   if cut_type[k] = "ray" then
      -sum{i in Luke1,j in Luke: j>=i+1}alfa1[i,j,k]*zr[i,j]*sum{q in i
+1..j}x2[i,q]
      -sum{i in Luke2,j in Luke: j<=i-1}beta1[i,j,k]*zr[i,j]*sum{q in
j..i-1}x2[i,q]
      -sum{i in Luke1,j in Luke: j>=i+1}xx1[i,j,k]*zr[i,j]*sum{q in
i..j-1}x2[q,j]
      -sum{i in Luke2,j in Luke: j<=i-1}delta1[i,j,k]*zr[i,j]*sum{q in
j+1..i}x2[q,j]
      +sum{i in 1..n-1,j in i+1..n: j!=i} fi1[i,j,k]*(C+MRS*(1-x2
[i,j]))
      +sum{i in 2..n,j in 1..i-1: j!=i} roi1[i,j,k]*(C+MRS*(1-x2
[i,j]))
      +tau1*(24*maxtt-sum{i in Luke,j in Luke:i!=j}x2[i,j]*(pdt[i]+pat
[j])-(l/v1+l/v2+tl+tb))
      +mi1*(24*mintt-sum{i in Luke,j in Luke:i!=j}x2[i,j]*(pdt[i]+pat
[j])-(l/v1+l/v2+tl+tb))
      +sum{i in Luke}lam1[i,k]*MRS+sum{i in Luke}rog1[i,k]*MRS>=0;
      -(dcc*maxtt-Pout*(l/v1+l/v2)*(scf*fp+scl*lp))-sum{i in Luke, j
in Luke}x2[i,j]*pec[j]>=0;

xcon1: sum{j in 2..n}x2[1,j]=1;

xcon2: sum{i in 2..n}x2[i,1]=1;

xcon3{q in 2..n-1}:sum{i in 1..q-1}x2[i,q]-sum{j in q+1..n}x2[q,j]=0;

xcon4{q in 2..n-1}:sum{i in q+1..n}x2[i,q]-sum{j in 1..q-1}x2[q,j]=0;

In first run cut_point and cut_ray are of course dropped, but solver
dose not take the initial value of variable Ship_pro into account and
therefore turns the problem infeasible.


Vlado

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