Try our new documentation site (beta).


Type: double
Modifiable: No

The variable value in a sub-optimal MIP solution. Use parameter SolutionNumber to indicate which alternate solution to retrieve. Solutions are sorted in order of worsening objective value. Thus, when SolutionNumber is 1, Xn returns the second-best solution found. When SolutionNumber is equal to its default value of 0, querying attribute Xn is equivalent to querying attribute X.

The number of sub-optimal solutions found during the MIP search will depend on the values of a few parameters. The most important of these are PoolSolutions, PoolSearchMode, and PoolGap. Please consult the section on Solution Pools for a more detailed discussion of this topic.

For examples of how to query or modify attributes, refer to our Attribute Examples.

Try Gurobi for Free

Choose the evaluation license that fits you best, and start working with our Expert Team for technical guidance and support.

Evaluation License
Get a free, full-featured license of the Gurobi Optimizer to experience the performance, support, benchmarking and tuning services we provide as part of our product offering.
Academic License
Gurobi supports the teaching and use of optimization within academic institutions. We offer free, full-featured copies of Gurobi for use in class, and for research.
Cloud Trial

Request free trial hours, so you can see how quickly and easily a model can be solved on the cloud.