# PreSOS1BigM

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### PreSOS1BigM

Threshold for SOS1-to-binary reformulation
 Type: double Default value: -1 Minimum value: -1 Maximum value: 1e10

Controls the automatic reformulation of SOS1 constraints into binary form. SOS1 constraints are often handled more efficiently using a binary representation. The reformulation often requires big-M values to be introduced as coefficients. This parameter specifies the largest big-M that can be introduced by presolve when performing this reformulation. Larger values increase the chances that an SOS1 constraint will be reformulated, but very large values (e.g., 1e8) can lead to numerical issues.

The default value of -1 chooses a threshold automatically. You should set the parameter to 0 to shut off SOS1 reformulation entirely, or a large value to force reformulation.

For examples of how to query or modify parameter values from our different APIs, refer to our Parameter Examples.

Please refer to this section for more information on SOS constraints.