Why am I not getting the m array?

1 view (last 30 days)
Hi all,
I have the following function:
function [m,yinter] = radial_lines(X,Y,xi,yi)
if X==Y
m=inf;
yinter= X;
return
end
% Calculate the slope:
m = (Y - yi)./((X) - xi);
% Solve for y-intercept
yinter = yi - m.*xi;
fplot(yinter)
end
%% data
X=[6,7,10,14,13,9];
Y=[12,9,7,8,10,14];
xi=10;
yi=10;
The issue i am running into is that when using the radial_lines function, I get a plot with horizontal lines. However I need the lines to have a slope. I am not quite sure what i am doing wrong when calculating the slopes. I should be getting an arry of m values but the code does not give me that output. Can some one kinldy help me out? Thanks.
  6 Comments
Torsten
Torsten on 1 Oct 2022
Edited: Torsten on 1 Oct 2022
Slope and y-intercept can be obtained from my answer given below.
X=[6,7,10,14,13,9];
Y=[12,9,7,8,10,14];
xi=10;
yi=10;
hold on
for i=1:6
plot([X(i),xi],[Y(i),yi])
end
hold off
Mariam Shahab
Mariam Shahab on 1 Oct 2022
Thank you for your help. This is the graph I was aimming for.

Sign in to comment.

Accepted Answer

Star Strider
Star Strider on 1 Oct 2022
That clears up much.
Plotting them is simply this —
%% data
X=[6,7,10,14,13,9];
Y=[12,9,7,8,10,14];
xi=10;
yi=10;
figure
plot([ones(size(X))*xi; X], [ones(size(Y))*yi; Y], '-k')
grid
axis([5 15 6 15])
axis('equal')
text(X*1.01,Y*1.01,compose('(%2d,%2d)',[X;Y].'))
It is not necessary to plot the individual regressions, although you can certainly do that if you want to. Getting the slopes and intercepts may be enough, and your function does that.
.

More Answers (1)

Torsten
Torsten on 1 Oct 2022
Edited: Torsten on 1 Oct 2022
yinter is not a function. So use "plot" instead of "fplot" (whatever abscissa data you might want to choose).
Not that yinter(3) = Inf which is not plotted.
%% data
X=[6,7,10,14,13,9];
Y=[12,9,7,8,10,14];
xi=10;
yi=10;
[m yinter] = radial_lines(X,Y,xi,yi)
m = 1×6
-0.5000 0.3333 Inf -0.5000 0 -4.0000
yinter = 1×6
15.0000 6.6667 Inf 15.0000 10.0000 50.0000
function [m,yinter] = radial_lines(X,Y,xi,yi)
for i=1:numel(X)
if X(i)==xi
m(i)=inf;
yinter(i)= inf;
else
% Calculate the slope:
m(i) = (Y(i) - yi)/(X(i) - xi);
% Solve for y-intercept
yinter(i) = Y(i) - m(i)*X(i);
end
end
end

Categories

Find more on Discrete Data Plots in Help Center and File Exchange

Community Treasure Hunt

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

Start Hunting!