How to draw first order best fit in case of hold on figure?

1 次查看（过去 30 天）
Safi ullah
Safi ullah 2018-1-9
评论： Star Strider 2018-1-10
Hi everybody, I have used the following code, and get the fig as shown below.
x = [9.384,39.27];
Y1 = 6.49e-12 * x.^(-4);
Y2 = 4.36e-10 * x.^(-5);
Y3 = 1.69e-10 * x.^(-4.3);
loglog(x,Y1,'*')
hold on
loglog(x,Y2,'*')
hold on
loglog(x,Y3,'*')
set(gca,'xtick',[9.384 39.27]);
set(gca,'xticklabel',{'A','B'});
Now I need to draw the best fit between A and B (best fit line draw from points at A towards points at B). I know the best fit in case of simple x and y plot, but due to hold on I do not know how to do this. Any guidance will be appreciated thanks.
  2 个评论
Image Analyst
Image Analyst 2018-1-9
What does hold on have to do with anything? Are you wanting to know how to use polyfit() to fit a line through the points, like this?
xt = [x(1), x(1), x(1), x(2), x(2), x(2)]
yt = [Y1(1), Y2(1), Y3(1), Y1(2), Y2(2), Y3(2)]
coefficents = polyfit(xt, yt, 1)
Safi ullah
Safi ullah 2018-1-9
@ Image Analyst thanks for response. Actually I want to to draw the best fit between the A and B points.

请先登录，再进行评论。

请先登录，再回答此问题。

采纳的回答

Star Strider
Star Strider 2018-1-10
Try this:
x = [9.384,39.27];
Y1 = 6.49e-12 * x.^(-4);
Y2 = 4.36e-10 * x.^(-5);
Y3 = 1.69e-10 * x.^(-4.3);
xv = reshape([x; x; x], [], 1); % Create X-Vector
YM = reshape([Y1; Y2; Y3], [], 1); % Create Y-Vector
DM = [xv(:) ones(size(xv(:)))]; % Design Matrix
B = DM \ YM; % Estimate Parameters
YFit = DM * B; % Fit Regression For Plot
figure(1)
loglog(x,Y1,'*')
hold on
loglog(x,Y2,'*')
loglog(x,Y3,'*')
loglog(xv, YFit, '-r') % Plot Regression
hold off
set(gca,'xtick',[9.384 39.27]);
set(gca,'xticklabel',{'A','B'});
  3 个评论
显示 1更早的评论
Safi ullah
Safi ullah 2018-1-10
@ Image Analyst, actually first I do not understand what you have mentioned in comment. As the answer of Star Strider exactly give me my problem solution and after your second comment I also understand your code. @ Image Analyst and Star Strider thanks both of you.

请先登录，再进行评论。

更多回答（0 个）

类别

在 Help Center 和 File Exchange 中查找有关 Uniform Distribution (Continuous) 的更多信息

标签

Community Treasure Hunt

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

Start Hunting!

Translated by