Add a new general constraint of type GRB.GENCONSTR_LOGA to a model.

A logarithmic function constraint states that the relationship <span>$</span>y = log_a(x)<span>$</span> should hold for variables <span>$</span>x<span>$</span> and <span>$</span>y<span>$</span>, where <span>$</span>a > 0<span>$</span> 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, FuncPiecesLength, and FuncPieceRatio. For details, consult the General Constraint discussion.

GRBGenConstr AddGenConstrLogA ( GRBVar xvar,
    GRBVar yvar,
    double a,
    string name,
    string options )

    xvar: The <span>$</span>x<span>$</span> variable.

    yvar: The <span>$</span>y<span>$</span> variable.

    a: The base of the function, <span>$</span>a > 0<span>$</span>.

    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").

    Return value:

    New general constraint.