RyR needs volumes of different compartments within the cell

V_myo = 21.5; % Intracellular volume
V_SR = V_myo*0.035; % SR volume
V_di = V_myo*0.0539; % diadic volume
V = struct();
V.V_myo = V_myo;
V.V_SR = V_SR;
V.V_di = V_di;


Currently, This is used only in RyR  module.
these volumes may be overwritten when replacing BG solver file.