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

15 vues (au cours des 30 derniers jours)
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
  1 commentaire
madhan ravi
madhan ravi le 14 Déc 2023
Modifié(e) : madhan ravi le 14 Déc 2023
Sure, give a simple example and expected output.

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Réponse acceptée

Paul
Paul le 15 Déc 2023
Modifié(e) : Paul le 15 Déc 2023
Assuming your 40x2 array is stored in a workspace varaiable named data.
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.
  8 commentaires
madhan ravi
madhan ravi le 15 Déc 2023
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
Robert Scott le 15 Déc 2023
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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Plus de réponses (2)

Andy Bartlett
Andy Bartlett le 14 Déc 2023
Modifié(e) : Andy Bartlett le 14 Déc 2023
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
  1 commentaire
Robert Scott
Robert Scott le 15 Déc 2023
This is not working.
I got the table working but the output valuesa are no where near where they should be.
It looks up a value of lets say 4, the corresponding value in the table is about .85
Instead the table pumps out .5
So i dont know how its doing this interpolation but its pretty far off

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Robert Scott
Robert Scott le 15 Déc 2023
You guys are putting in great effort here to help.
Thank you!
For the life of me i cant make this work. I got rid of all the complicated code as you did and it still wont work. Here is a screen shot
  1 commentaire
Robert Scott
Robert Scott le 15 Déc 2023
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

Connectez-vous pour commenter.

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