how to create a look up table to use in simulink from a 2D array of doubles

Question

Robert Scott 2023-12-13

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https://ww2.mathworks.cn/matlabcentral/answers/2060369-how-to-create-a-look-up-table-to-use-in-simulink-from-a-2d-array-of-doubles

评论： Robert Scott 2023-12-15

采纳的回答： Paul

I have a simple 2 day array that is 40x2

I want to make it a look up table for simulink.

it needs to be interpolated not a direct.

So i want simulink to scan the first column and find the value closed to the one im inputting and them pump out the value in the second column that corresponds to the input found in column one.

This should be really simple. Can someone lend a hand?

thanks

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madhan ravi 2023-12-14

编辑：madhan ravi 2023-12-14

Sure, give a simple example and expected output.

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Answer 1

Paul 2023-12-15

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编辑：Paul 2023-12-15

Assuming your 40x2 array is stored in a workspace varaiable named data.

Use the 1D Lookup Table.

Set the Table Data parameter to data(:,2)

Set the Breakpoints parameter to data(:,1)

Set the Interpolation Method to Nearest.

Depending on the structure of data(:,1) make sure to check into the following block parameters: Index search method, and Begin index search using previous index result

I think this addresses the problem as stated in the question. But the question also mentioned interpolation, and there is no interpolation happening here.

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madhan ravi 2023-12-15

Paul you could show the picture of Table and breakpoints field so that it is clear for OP how to define them in Simulink.

Robert Scott 2023-12-15

Wow im an idiot.

I figured it out.

I guess i did not understand what the meaning of break point is.

Why dont they just call it data in and data out..... (headbang!)

Thank you guys for help so much! Great support great community. Im just a goober.

Happy Holidays folks

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Answer 2

Andy Bartlett 2023-12-14

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https://ww2.mathworks.cn/matlabcentral/answers/2060369-how-to-create-a-look-up-table-to-use-in-simulink-from-a-2d-array-of-doubles#answer_1371823

编辑：Andy Bartlett 2023-12-14

在 MATLAB Online 中打开

To create a Simulink 1D Lookup Table block using the data from your 2D matrix variable,

modify this script to meet your needs and run it.

% fake creation of data
%
npts = 5;
x = linspace(0.1,1,npts).';
y = exp(1.234*x);
data2D = [x, y];
% Create model containing 1D LUT block
%
rand_trailing_string = dec2hex( randi([0,2^32-1],1,1), 8 );
mdl = sprintf('myRandModelName_%s',rand_trailing_string);
sourceLUT1 = sprintf('simulink/Lookup\nTables/1-D Lookup\nTable');
destinationLUT1 = [mdl,'/LUT'];
new_system(mdl);
open_system(mdl);
add_block( sourceLUT1, destinationLUT1)
dataConnectionApproach = 'inline';
switch dataConnectionApproach
    case 'inline'
        % explicitly inline the data values
        % Hint: mat2str is super helpful here
        %
        stringForBreakpoints = mat2str(data2D(:,1),17,'class');
        stringForTableData = mat2str(data2D(:,2),17,'class');
    otherwise
        % Reference data in workspace by variable name
        % Note: data must always be defined before model is used 
        %       in the future
        %
        stringForBreakpoints = 'data2D(:,1)';
        stringForTableData ='data2D(:,2)';
end
set_param(destinationLUT1, 'BreakpointsForDimension1', stringForBreakpoints);
set_param(destinationLUT1, 'Table', stringForTableData );
% Make additional changes to LUT as desired
% Either
%    Manually
% or
%    use set_param
%
% Hint to see names of parameters to use  with set_param do
%
%    get_param(gcb,'DialogParameters')
%
open_system(destinationLUT1)   % open for manual changes