function x = calculateNormalizedPsi(gridfile)
    % CALCULATENORMALIZEDPSI 计算归一化的psi值
    %   输入：gridfile - 网格文件路径
    %   输出：x - 归一化的psi值数组
    
    % 读取网格文件
    [varname, gridvalue] = readgridnc(gridfile);
    
    % 提取所需的变量
    psixy = gridvalue{strcmp(varname, 'psixy')};
    psi_axis = gridvalue{strcmp(varname, 'psi_axis')};
    psi_bndry = gridvalue{strcmp(varname, 'psi_bndry')};
    
    % 计算归一化的psi值
    x = (psixy(:,1) - psi_axis) / (psi_bndry - psi_axis);
end

function rho = calculateNormalizedr(gridfile)
    % 计算归一化rho的值
    [varname, gridvalue] = readgridnc(gridfile);
    ShiftAngle = gridvalue{strcmp(varname, 'ShiftAngle')};
    q = abs(ShiftAngle/2/pi);
    Rxy = gridvalue{strcmp(varname, 'Rxy')};
    [~, col_index] = max(max(Rxy));
    R0=(max(max(Rxy))+min(min(Rxy)))/2;
    a=max(max(Rxy))-R0;
    r=Rxy(:,col_index)-R0;
    rho=r/a;
end

极向磁通与归一化半径具有以下转换关系：
其中p是q在psi=1时的值，q是安全因子。