Finding data on specific point from large set data

Question

AMAN GUPTA 2022-3-9

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https://ww2.mathworks.cn/matlabcentral/answers/1667194-finding-data-on-specific-point-from-large-set-data

评论： AndresVar 2022-4-15

I have a folder named 'THETHA'. Inside folder I have 360 csv file named '1.csv', '2.csv',...'360.csv'. Each csv file has a data of temperature for different location (X ,Y, Z ,T). Each csv file has different number of rows because result is generated from comsol. I want to estimate temperature on specific point in each csv file. I have made another folder named "DATA" which contains my specific point(X, Y ,Z) in which i want to estimate temperature in each csv file. It is possible that our specific point may not be in csv file so i need to find temperature on that point with the help of interpolation. I am attaching my 'DATA' file and one csv file. Please help me.

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Answer 1

AndresVar 2022-3-9

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https://ww2.mathworks.cn/matlabcentral/answers/1667194-finding-data-on-specific-point-from-large-set-data#answer_913439

编辑：AndresVar 2022-3-9

在 MATLAB Online 中打开

Import data (e.g. right click file -> Import data... -> generate code)
Use scattered interpolant: Interpolating Scattered Data - MATLAB & Simulink (mathworks.com)

clear;
%%% get XYZ locations to interpolate
opts = delimitedTextImportOptions("NumVariables", 3);
opts.DataLines = [1, Inf];
opts.Delimiter = ",";
opts.VariableNames = ["VarName1", "VarName2", "VarName3"];
opts.VariableTypes = ["double", "double", "double"];
opts.ExtraColumnsRule = "ignore";
opts.EmptyLineRule = "read";
data = readtable("DATA.csv", opts);
XYZq = table2array(data);
%%% import data from a Theta file
clearvars opts;
opts = delimitedTextImportOptions("NumVariables", 4);
opts.DataLines = [10, Inf];
opts.Delimiter = ",";
opts.VariableNames = ["X", "Y", "Z", "TKThetha1"];
opts.VariableTypes = ["double", "double", "double", "double"];
opts.ExtraColumnsRule = "ignore";
opts.EmptyLineRule = "read";
data = readtable("1.csv", opts);
data = table2array(data);
% create a scattered interpolant object
T_data = scatteredInterpolant(data(:,1:3),data(:,4));
% interpolate the values
T_interp = T_data(XYZq)

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AndresVar 2022-3-30

在 MATLAB Online 中打开

what do the numbers represent?

Anyway, here is one way

XYZq = csvread("DATA.csv");
num1s = 1:71;
num2s = 1:41;
T_interp = nan(size(XYZq,1),numel(num1s),numel(num2s)) % 3 dimensions
for num1 = num1s
    for num2 = num2s
        dataFilename = sprintf("%d_%d.csv",num1,num2)
        data = csvread(dataFilename,9)
        T_data = scatteredInterpolant(data(:,1:3),data(:,4));
        
        T_interp(:,num1,num2) = T_data(XYZq);
    end
end

The alternative is you put the csv files in a folder and read all. for each file make a variable name and assignit in a table or struct. This would be useful if you don't know num1s and num2s

AMAN GUPTA 2022-3-30

Thank you so much @AndresVar

Actually I have extracted these csv files from COMSOL Multiphysics. I have 2 variable parameter angle and radius. I have guess 41 value of angle and 71 value of radius so will get total 41*71=2911 combination. for each combination I have generated Temperature profile in COMSOL Multiphysics. so for each value of guess radius there will be 41 value of angle so I have given the name like this.

In this code I am facing one problem that my 41*71=2911 Temperature Profile is not in the form of Excel sheet. Can you please help me @AndresVar so that I can get my 2911 temperature profile in the form of excel data and i can use this data further in my calculation

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Answer 2

AMAN GUPTA 2022-4-10

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https://ww2.mathworks.cn/matlabcentral/answers/1667194-finding-data-on-specific-point-from-large-set-data#answer_939100

@AndresVar can you please help me for some modification?

now file name changes as '1_1_1.csv', '1_1_2.csv', ...'1_1_11'.csv, '1_2_1.csv', '1_2_2.csv', ..'1_2_11.csv',............'1_9_11.csv', '21_1_1.csv', '21_1_2.csv',.. '21_1_11.csv', '21_2_1.csv', '21_2_2.csv', '21_2_11.csv'.......'21_9_1.csv','21_9_2.csv', '21_9_11.csv'.

now how can i modify this code to get my desire data?.

Please help me.