How can I find the difference between two plots with a dimensional mismatch ?

Hello all,

I have a question that I don't know if there is a solution off the bat.

Here it goes,

I have two data sets, that I have plotted on the same figure. I need to find their difference, simple so far... the problem arises in the fact that say matrix A has 1000 data points while the second (matrix B) has 580 data points. How will i be able to find the difference between the two graphs since their is a dimensional miss match between the two figures.

One way that I thought of is artificially inflating matrix B to 1000 data points, but the trend of the plot will remain the same. Would this be possible? and if yes how?

Answer 1

[Walter Roberson]

all_x = unique([x_from_A(:); x_from_B(:)]);
refined_A = interp1(x_from_A, A, all_x);
refined_B = interp1(x_from_B, B, all_x);
plot(all_x, refined_B - refined_A)

[Giorgos]

does this come with an explenation of what exactly the solution to my problem is?

THanks BTW :)

[Giorgos]

Yeah I see what you did but extending the range of the matrix with NaN'S doesn't really work when you later whant to subtract them, take for example this code:

A=[1 2 3 4 5 ];

B=[11 22 33 44 55 66 77 88 99 1010];

Ya=A.*20+4;

Yb=B./10+3;

all_x = unique([A(:); B(:)])

refined_A = interp1(A, Ya, all_x);

refined_B = interp1(B, Yb, all_x);

C=refined_B - refined_A

plot(A,Ya,'r',B,Yb)

xlim([-100 1000])

grid on hold on

plot(all_x, C)

you will notice that the cells of C are filled with NaN's...

Do you have any suggestions on how to bypass this problem?