This keyword specifies the number of quadrature points per Å2 to use in surface terms (e.g., molecular surface, solvent accessible surface) for apolar calculations. The keyword is ignored when srad is 0.0 (e.g., for van der Waals surfaces) or when srfm is spl2 (e.g., for spline surfaces). The syntax is sdens {density} density is a floating point number indicating the number of grid points per Å2.Users beware: there is a direct correlation between the value used for the sphere density, the accuracy of the results, and the APBS calculation time. |