Add a new general constraint of type GRB.GENCONSTR_LOGA to a model.
A logarithmic function constraint states that the relationship should hold for variables and , where is the (constant) base.
A piecewise-linear approximation of the function is added to the model. The details of the approximation are controlled using the following four attributes (or using the parameters with the same names): FuncPieces, FuncPieceError, FuncPieceLength, and FuncPieceRatio. For details, consult the General Constraint discussion.
xvar: The variable.
yvar: The variable.
a: The base of the function, .
name: Name for the new general constraint.
options: A string that can be used to set the attributes that control the piecewise-linear approximation of this function constraint. To assign a value to an attribute, follow the attribute name with an equal sign and the desired value (with no spaces). Assignments for different attributes should be separated by spaces (e.g. "FuncPieces=-1 FuncPieceError=0.001").
New general constraint.