Radius of gyration calculator

This Javascript calculates the Radius of Gyration of concentric shell models. Select the number of shells, the lengths of the respective semi-axis Rx(i), Ry(i) and Rz(i) (z is in the axis of rotation) and the corresponding electron-density c(i) between R(i-1) <= R(i), with R(1) being the innermost shell and R(n) the outermost shell, respectively. The values of the radius of gyration Rg and of the zero-angle intensity I(0), respectively, will be calculated. Units are arbitrary and in metric dimensions (usually in Å or nm). In case of models extending infinitely in the 3rd dimension, Rg of the cross-section (circle, ellipse or rectangle, Rz is set to 0), and in case of models spreading infinitely in two dimensions, Rg of the thickness (line, Rx and Ry are set to 0) will be calculated, respectively. In case of a torus, Rz is defined as the semi-axis of the torus (from the center of the torus to the center of the tubular cross-section, where Rz(i) must be the same for all shells and Rzb/Rza is the factor by which Rz (=Rza) is multiplied to get the value for the other semi-axis (=Rzb) of the torus), Rx(i) and Ry(i) are the semi-axes of the tubular cross-section (o: round, #: rectangular) of the torus with Rx(i) parallel to Rz and Ry(i) normal to Rz.