Hi everyone

I am working on a complementary problem with the following equations and constraints:

minimize obj: 0;

# Constraints

s.t. linkflow_eq {i in 1…80}: LinkFlows[i] = sum{j in CumulativeLengthData[i-1]+1…CumulativeLengthData[i]} x[flatData[j]];

# Calculating Costs

s.t. cost_eq {i in 1…Total_Num_Var}: cost[i] = sum{j in 1…76: MX[i,j] == 1} (LinkINFO[j,1]*(1+ LinkINFO[j,3]*(LinkFlows[j]/(LinkINFO[j,2]))^LinkINFO[j,4])) + sum{j in 77…80: MX[i,j] == 1} ((LinkFlows[j]/700) + ((MX[i,LengthDataSize+2]*Price[MX[i,LengthDataSize+6]]) / (gamma * Ruo)) + ((MX[i,LengthDataSize+2]) / (gamma * rate)))*60 ;

# Complementary Constraint

s.t. con2{i in 1…Total_Num_Var}: x[i] >= 0 complements (cost[i] - Cstar[MX[i,LengthDataSize+1]]) >= 0;

# Demand Constraint

s.t. ODMatrixL_eq{i in 1…576}: sum{j in 1…Total_Num_Var: MX[j,LengthDataSize+1] == i} x[j] = Demand_L[i];

**If you look at the formulation of the cost, there is a Price vector variables. I expect that by changing the value of parameters such as price vector, I get two type of result: infeasible or solution found. But there are some result that the output of AMPL is the following message:**

** EXIT - other error.

Major Iterations. . . . 46

Minor Iterations. . . . 41413

Restarts. . . . . . . . 3

Crash Iterations. . . . 17

Gradient Steps. . . . . 24

Function Evaluations. . 715

Gradient Evaluations. . 67

Basis Time. . . . . . . 309.366000

Total Time. . . . . . . 322.828000

Residual. . . . . . . . 1.078515e+04

Postsolved residual: 1.0785e+04

Path 5.0.05: Not enough progress.

63 iterations (17 for crash); 41413 pivots.

715 function, 67 gradient evaluations.

**What is the reason for that? I would appreciate it if you could guide me.**