function Output = MALookupTable(varargin)
% MALookupTable: generate a look-up table for Mandel-Agol model values, or
% use the table and read from it

%Inputs: 'init' - calculate a table of the MA values for the given rVec,
%zVec, u1, u2
%           'load' = return all the table and the row/col values in a
%           structure
%           r,z = return the Mandel-Agol model values for the given r,z.
%           u1 and u2 which will be used are the ones that were used for
%           generating the table. z can be a vector, r must be a scalar.

% Yair Judkovsky, 25.10.2020

persistent rVec zVec u1 u2 R Z MATable

%return a specific Mandel-Agol model value
if isnumeric(varargin{1})
    
    %get r, z values from the input
    r = varargin{1};
    z = varargin{2};
    Requested_u1 = varargin{3};
    Requested_u2 = varargin{4};
    
    %if no table exists, or if the requested u1,u2 do not match the table, just calculate the values
    if isempty(MATable) || Requested_u1~=u1 || Requested_u2~=u2
        Output = occultquadVec(r,z,Requested_u1,Requested_u2);
        return
    end
    
    Output = ones(size(z));
    
    %old method - plug in "1" wherever outside the planet radius range
%     Output(z<1+r) = interp2(R,Z,MATable,z(z<1+r),r,'linear',1);
    
    %new method - outside the radius range calculate using occultquadVec. This
    %is useful because now the radius range can be reduce, yielding a fast
    %calculation for most of the points
    ind = r>min(rVec) & r<max(rVec);
    Output(z<1+r & ind) = interp2(R,Z,MATable,z(z<1+r & ind),r,'linear');
    Output(z<1+r & ~ind) = occultquadVec(r,z(z<1+r & ~ind),u1,u2);
    
    return
    
end

%perform the calculation. Table will be made such that each row represents
%a value of r, and each column represents a value of z
if isequal(varargin{1},'init')
    
    %set range of r, z, u1, u2. Can also be read from varargin if
    %exists, where the 2,3,4,5 arguments will be rVec, zVec, u1, u2.
    rVec = 0.5e-2:2e-3:0.2;
    zVec = 0:2e-3:1.25;
    u1 = 0.36;
    u2 = 0.28;

    
    
    %read inputs from varargin, if they exist
    if length(varargin)==5
        rVec = varargin{2};
        zVec = varargin{3};
        u1 = varargin{4};
        u2 = varargin{5};
    end
    
    %generate a table of r and z values
    [R,Z] = meshgrid(zVec,rVec);
    
    %set a table of model values for r and z
    MATable = zeros(length(rVec),length(zVec));
    for j = 1:length(rVec)
        MATable(j,:) = occultquadVec(rVec(j),zVec,u1,u2);
    end
    
    fprintf('calculated Mandel-Agol values \n');
    
    Output = [];
    return
end

%load the table
if isequal(varargin{1},'load')
    Output.rVec = rVec;
    Output.zVec = zVec;
    Output.u1 = u1;
    Output.u2 = u2;
    Output.R = R;
    Output.Z = Z;
    Output.MATable = MATable;
    return
end

%clear the values
if isequal(varargin{1},'clear')
    clear rVec zVec u1 u2 R Z MATable
    Output = [];
    return
end