GAMS World Forum

Sorry, for threads = 4 case, the elapsed time is 5min38sec.

Gabriel

Hi all, I have tried to set different threads for CPLEX solver to facilitate my computation, but weirdly, different threads gave different final results. Based on my knowledge, setting threads will only influence the speed because it is for parallel computing, but will not have any impact on the exe...

Hi all, I am using a linux-version GAMS in a linux system. It does give me a .lst file after compilation, but it cannot be viewed as in GAMS IDE, like shown in the following. .lst file in a GAMS IDE is with very fancy labels and can be easily viewed. https://image.ibb.co/b9damp/lst.jpg I have tried ...

Gabriel, From the log output you sent I would conclude that the GAMS/CPLEX link has found a general non-linear constraint in your problem. Simply put, it does not think it is a QCP. The specific output I refer to is: General nonlinearity detected in row subobjregu -Steve Thank you! However, the row...

Hi, Perhaps you have use x**2 to represent your quadratic part. **2 is the real power (https://www.gams.com/latest/docs/UG_Parameters.html#INDEX_power_2d__21_function) and can't be used in QCP models. So better use power(x,2) or even simpler sqr(x) . -Michael Thank you! Actually I was using abs() w...

Thanks for your kind reply! That should be the best solution!

Gabriel

Hi all, I got one issue reporting "System Failure". My opt. problem has a mixed-integer quadratic objective function with linear constraints, and I defined it as an MIQCP problem. the report summary is as follows. S O L V E S U M M A R Y MODEL dualspregu OBJECTIVE subdualregu TYPE MIQCP DI...

Sorry but I found the solution myself :D And I apologize for the error in the post that I use 'n' twice for index. I share my solution with you. loop(i, ... loop(n, s(n) = a('1') - a(n); ); if(sum(n, s(n)) = 0, k = 1; ); break$(k = 1); continue; ); If you have better idea please share with me too! T...

Hi all, Long time no see! I have one question about the implementation of continued equality for a break condition of my algorithm. I want to achieve the following pseudocode: If: a(1) = a(2) = a(3) = ... = a(n), then Break; else: Continue; In a GAMS code manner: loop(n, ... break$(a(1)=a(2) and a(1...

The former one is simple and efficient. I never use the latter method to do this so I do not know which one performs better w.r.t. running time. But the former one is simply good and easy to implement. Execution time of the solver might not be influenced with how you define the variable. But the lat...