How can I use a loop to maximize correlation of multiple graphs?

3 次查看（过去 30 天）
Mary Juno
Mary Juno 2020-1-6
评论： Mary Juno 2020-1-7
I have data that is made up of a (mostly) horizontal line, a sloped line, and another horizontal line, as shown below. I am trying to get a best fit for each section and have tried to do this using the correlation coefficient. What I would like to do is create a loop that will determine the best location (j and k variables) to get the length of sections that result in the best fit for the sloped section.
Sample Plot.PNG
Many of the things I have tried don't work because the correlation is dependent on the values of j and k, making the solution iterative rather than something that could be solved using fminsearch or similar solvers.
Thank you for any help!
function CrackLocationFIT
file = 'FileName.xlsx'
T = readtable(file, 'Sheet', 'Sheet Name'); %import table from excel
[a,~]=size(T); %determine size of imported table
n = a;
increment = 13; %number of lines to skip when reading excel files
xdata = 0:199; %number of data points
for i = 15:increment:n
A = xlsread(file, 'Sheet Name', strcat('C',num2str(i),':GT',num2str(i))); %read y-coordinates from the excel sheet
scatter(xdata,A,'k', '.') %plot scatter for data set
j = 25;
k = 140;
sec1 = 0:(j-1);
sec2 = j:(k-1);
sec3 = k:199;
P1 = mean(A(:,1:j));
P2 = polyfit(sec2,A(:,(j+1):(k)),1);
P3 = mean(A(:,(k+1):200));
yfit1 = repmat(P1(1),1,length(sec1));
yfit2 = P2(1)*sec2+P2(2);
yfit3 = repmat(P3(1),1,length(sec3));
c1 = corrcoef(yfit1,A(:,1:j));
c2 = corrcoef(yfit2,A(:,(j+1):(k)));
c3 = corrcoef(yfit3,A(:,(k+1):200));
plot(sec1,yfit1,'-r') %plot data for data set 1
plot(sec2,yfit2,'-r') %plot data for data set 2
plot(sec3,yfit3,'-r') %plot data for data set 3
xlabel('Location Along Perpendicular Line')
xlim([0 199]) %set x limit for uniform plot
ylabel('Y Displacement [in,]')
title(graphtitle)
hold on
end
hold off
end

请先登录，再回答此问题。

采纳的回答

Stijn Haenen
Stijn Haenen 2020-1-6
Maybe something like this can help you:
clear
Y_data=[ones(1,40)*-6,-6:-2/20:-8,ones(1,140)*-8]; %just an example
for x1=1:197
for x2=x1+2:199
hor_section_1=ones(x1,1)*mean(Y_data(1:x1)); %first horizontal section
hor_section_2=ones(200-x2,1)*mean(Y_data(200-x2:200)); %second horizontal section
slope=hor_section_1(1):(hor_section_2(1)-hor_section_1(1))/(x2-x1):hor_section_2(1); %slanting line inbetween
line=[hor_section_1(:)',slope(:)', hor_section_2(:)'];
corr0(x1,x2)=sum(Y_data.*line)/sqrt(sum(Y_data.^2)*sum(line.^2));
end
end
[a,b]=find(corr0==max(corr0(:)));

更多回答（0 个）

类别

在 Help Center 和 File Exchange 中查找有关 Loops and Conditional Statements 的更多信息

标签

产品

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by