function [ar_forbrblk, ar_forbrblk_r] = ffs_for_br_block_gen(varargin)

%% FFS_FOR_BR_BLOCK_GEN formal borrowing blocks

% Grid of formal borrowing points with associated interest rates. Policies

% could shift this. This function could be invoked to generate multiple

% formal borrowing grids from multiple formal borrowing providers, and the

% overall formal borrowing choice set is a combination of these grids. 

%

% @param fl_r_fbr boolean single formal borrowing interest rate

%

% @param st_forbrblk_type string different formal borrowing grid

% structures, some for testing/illustration purposes. Estimation uses real

% observed blocks from data.

%

% @param st_forbrblk_type string different formal borrowing grid

% structures, some for testing/illustration purposes. Estimation uses real

% observed blocks from data.

%

% # *unif*: uniform grid equal gap from min to

% # *seg3*: three segment blocks, the first 1/3 gap of the third segement,

% respect min and max from fl_forbrblk_brmost and fl_forbrblk_brleast,

% smallest borrowing segment gap is fl_forbrblk_gap

%

% @param fl_forbrblk_brmost float maximum formal borrowing allowed on grid,

% , might not not be relevant for all _st_forbrblk_type_

%

% @param fl_forbrblk_brleast float minimum formal borrowing allowed on

% grid, might not be relevant for all _st_forbrblk_type_

%

% @param fl_forbrblk_gap float formal borrowing grid gap, means different

% things for different _st_forbrblk_type_

%

% @return ar_forbrblk array array of formal borrowing grid points. should

% be ordered from lowest to highest including zero at the top. i.e.: [-4,

% -2, -1, 0]. These are assumed to be in principles units always.

% PRINCIPLES only, do not include interest rates.

%

% @return ar_forbrblk_r array interest rates associated with equal-length

% _ar_forbrblk_. ar_forbrblk_r multiplied element-wise with ar_forbrblk

% will provide the principle + interest rates associated with each formal

% borrowing grid elements. 

%

% @example

%

%   [ar_forbrblk, ar_forbrblk_r] = ...

%        ffs_for_br_block_gen(fl_r_fbr, st_forbrblk_type, fl_forbrblk_brmost, fl_forbrblk_brleast, fl_forbrblk_gap);

%

% @seealso

%

% * Formal Borrowing Grid: <https://fanwangecon.github.io/CodeDynaAsset/m_fibs/paramfunc_fibs/html/ffs_for_br_block_gen.html ffs_for_br_block_gen>

% * Informal Interest Rates: <https://fanwangecon.github.io/CodeDynaAsset/m_fibs/paramfunc_fibs/html/ffs_r_inf.html ffs_r_inf>

% * Match Borrowing to Formal Grid: <https://fanwangecon.github.io/CodeDynaAsset/m_fibs/paramfunc_fibs/html/ffs_for_br_block_match.html ffs_for_br_block_match>

% * Optimize Formal and Informal, Borrowing and Savings Joint Choices: <https://fanwangecon.github.io/CodeDynaAsset/m_fibs/paramfunc_fibs/html/ffs_fibs_min_c_cost.html ffs_fibs_min_c_cost>

% * Bridge Loan: <https://fanwangecon.github.io/CodeDynaAsset/m_fibs/paramfunc_fibs/html/ffs_fibs_inf_bridge.html ffs_fibs_inf_bridge>

% * Overall Optimization: <https://fanwangecon.github.io/CodeDynaAsset/m_fibs/paramfunc_fibs/html/ffs_fibs_min_c_cost_bridge.html ffs_fibs_min_c_cost_bridge>

% * Discrete Choices: <https://fanwangecon.github.io/CodeDynaAsset/m_fibs/paramfunc_fibs/html/ffs_fibs_identify_discrete.html ffs_fibs_identify_discrete>

%

%% Default

fl_r_fbr = 0.045; 

[st_forbrblk_type, fl_forbrblk_brmost, fl_forbrblk_brleast, fl_forbrblk_gap] = deal('seg3', -19, -1, -1.5); 

bl_display_forbrblock = false; 

default_params = {fl_r_fbr st_forbrblk_type fl_forbrblk_brmost fl_forbrblk_brleast fl_forbrblk_gap ... 

    bl_display_forbrblock}; 

%% Parse Parameters

% numvarargs is the number of varagin inputted

[default_params{1:length(varargin)}] = varargin{:}; 

[fl_r_fbr, st_forbrblk_type, fl_forbrblk_brmost, fl_forbrblk_brleast, fl_forbrblk_gap, ... 

    bl_display_forbrblock] = default_params{:}; 

%% Set Formal Borrowing Grid Uniform

if (strcmp(st_forbrblk_type, 'unif')) 

    ar_forbrblk = fl_forbrblk_brleast:fl_forbrblk_gap:fl_forbrblk_brmost;

end

%% Set Formal Borrowing Grid Three Segment

% An example grid with three segments, the first segement has

% fl_forbrblk_gap as gap, the second segment gap is twice, the third

% segement the gap is 3 times as large as fl_forbrblk_gap. Respect

% fl_forbrblk_brmost fl_forbrblk_brleast, which means divided into three

% parts based on them as much as possible

if (strcmp(st_forbrblk_type, 'seg3')) 

    fl_most_least_gap = (fl_forbrblk_brmost - fl_forbrblk_brleast); 

    fl_most_least_seg3_interval = fl_most_least_gap/3; 

    ar_seg1 = fl_forbrblk_brleast:fl_forbrblk_gap:fl_most_least_seg3_interval; 

    ar_seg2 = max(ar_seg1):(fl_forbrblk_gap*2):fl_most_least_seg3_interval*2; 

    ar_seg3 = max(ar_seg2):(fl_forbrblk_gap*3):fl_forbrblk_brmost; 

    ar_forbrblk =[ar_seg1, ar_seg2, ar_seg3]; 

end 

%% Set Formal Borrowing Grid Three Segment

% An example grid with three segments, the first segement has

% fl_forbrblk_gap as gap, the second segment gap is twice, the third

% segement the gap is 3 times as large as fl_forbrblk_gap. Respect

% fl_forbrblk_brmost fl_forbrblk_brleast, which means divided into three

% parts based on them as much as possible

if (strcmp(st_forbrblk_type, 'testfx')) 

    fl_most_least_gap = (fl_forbrblk_brmost - fl_forbrblk_brleast);

    fl_most_least_seg3_interval = fl_most_least_gap/3;

    ar_seg1 = fl_forbrblk_brleast:fl_forbrblk_gap:fl_most_least_seg3_interval;

    ar_seg2 = max(ar_seg1):(fl_forbrblk_gap*2):fl_most_least_seg3_interval*2;

    ar_seg3 = max(ar_seg2):(fl_forbrblk_gap*3):fl_forbrblk_brmost;

    ar_forbrblk =[-3 -6];

end

%% Sort Borrowing Blocks

% add zero because formal borrowing = 0 should be an option

ar_forbrblk = [-0 ar_forbrblk]; 

ar_forbrblk = sort(unique([ar_forbrblk])); 

%% Generate Corresponding Interest Rates Arrays

ar_forbrblk_r = fl_r_fbr + zeros(size(ar_forbrblk)); 

if (bl_display_forbrblock) 

    disp('ar_forbrblk');

    disp(ar_forbrblk);

    disp('ar_forbrblk_r');

    disp(ar_forbrblk_r);

end

end