<html><head></head><body><div style="font-family: Verdana;font-size: 12.0px;"><div>Hi Divyayan,</div>
<div> </div>
<div>the initial solution is only useful to Couenne as a cutoff, i.e. a value such that the portion of solution space with objective above it is excluded from the search.</div>
<div> </div>
<div>If the optimal solution you get is unsatisfactory, it might be a matter of modeling. If the solution you found satisfies all constraints and minimizes the objective, the only way to receive a more "balanced", as I assume you're looking for, solution is to change the model itself.</div>
<div> </div>
<div>Hope this helps. Regards,</div>
<div>Pietro
<div>
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<div style="margin:0 0 10px 0;"><b>Sent:</b> Monday, May 18, 2020 at 4:03 AM<br/>
<b>From:</b> "Divyayan Dey" <divyayanrishi@gmail.com><br/>
<b>To:</b> couenne@list.coin-or.org<br/>
<b>Subject:</b> [Couenne] Regarding optimization issues with couenne</div>
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<div><span style="font-family: sans-serif;font-size: 12.8px;">Sir,</span>
<div style="font-family: sans-serif;font-size: 12.8px;">I am Divyayan Dey, an Electronics and Communication Engineering student from India. </div>
<div style="font-family: sans-serif;font-size: 12.8px;">I am solving an optimization problem using couenne solver in Pyomo(the problem being non-convex). I have a finite capacity to distribute among a set of elements. However, with any initial guess <img alt="x0" height="11" src="https://s0.wp.com/latex.php?zoom=3&bg=ffffff&fg=000000&s=0&latex=x0" style="display: inline;vertical-align: -0.333px;" width="16"/> provided to the solver, the optimized vector is messed up badly; e.g., with a capacity of 1000 to distribute ,the optimized vector <img alt="x" height="7" src="https://s0.wp.com/latex.php?zoom=3&bg=ffffff&fg=000000&s=0&latex=x" style="display: inline;" width="8"/> gives [897,1,1,1,1....] . With a capacity of 500, the vector <img alt="x" height="7" src="https://s0.wp.com/latex.php?zoom=3&bg=ffffff&fg=000000&s=0&latex=x" style="display: inline;" width="8"/> is [397,1,1,...]. And when the optimization is done only in the convex portion of the objective function, the initial guess <img alt="x0" height="11" src="https://s0.wp.com/latex.php?zoom=3&bg=ffffff&fg=000000&s=0&latex=x0" style="display: inline;vertical-align: -0.333px;" width="16"/> is returned itself showing no evaluations done. What could be a possible reason for this? I can add the code if you would like to introspect. </div>
<div style="font-family: sans-serif;font-size: 12.8px;"> </div>
<div style="font-family: sans-serif;font-size: 12.8px;">Thanks. Regards,</div>
<div style="font-family: sans-serif;font-size: 12.8px;">Divyayan Dey </div>
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