Straight line from all points of A to every single point of B

Hi everybody,

i have 2 array with different number of rows (with columns that indicate x, y and z):

A (3x3 duble)

2.5 6.6 9.5

1.6 6.6 2.8

2.6 0.9 1.8

B (4x3 duble)

2.4 6.7 9.8

2.6 6.9 7.8

2.9 7.7 5.8

3.4 8.8 4.8

I want to track the straight line which passes from all points of A to every single point of B. I made this script but it does not run:

[m,n]=size(B)

[o,p]=size(A)

STR=-20:.01:20;

for i = 1:m

C{i}=repmat(A(1:o,:),length(STR),1)'+((B(i,:))-A(1:o,:))'*STR;

end

How can i do it? Thank you!

[Jan]

The question is not clear yet. What does "track a straight line" mean? What is the wanted output?

[Riccardo Rossi]

Thank you for the answer. I would like to obtain something like this:

C{1,1}=repmat(A(1,:),length(STR),1)'+((B(1,:))-A(1,:))'*STR;

C{1,2}=repmat(A(1,:),length(STR),1)'+((B(2,:))-A(1,:))'*STR;

C{1,3}=repmat(A(1,:),length(STR),1)'+((B(3,:))-A(1,:))'*STR;

C{1,4}=repmat(A(1,:),length(STR),1)'+((B(4,:))-A(1,:))'*STR;

C{1,5}=repmat(A(2,:),length(STR),1)'+((B(1,:))-A(2,:))'*STR;

C{1,6}=repmat(A(2,:),length(STR),1)'+((B(2,:))-A(2,:))'*STR;

C{1,7}=repmat(A(2,:),length(STR),1)'+((B(3,:))-A(2,:))'*STR;

C{1,8}=repmat(A(2,:),length(STR),1)'+((B(4,:))-A(2,:))'*STR;

C{1,9}=repmat(A(3,:),length(STR),1)'+((B(1,:))-A(3,:))'*STR;

C{1,10}=repmat(A(3,:),length(STR),1)'+((B(2,:))-A(3,:))'*STR;

C{1,11}=repmat(A(3,:),length(STR),1)'+((B(3,:))-A(3,:))'*STR;

C{1,12}=repmat(A(3,:),length(STR),1)'+((B(4,:))-A(3,:))'*STR;

[Riccardo Rossi]

Is it possible?

Answer 1

[Jan]

With some guessing:

nB  = size(B, 1)
nA  = size(A, 1)
STR = -20:.01:20; 
n   = numel(STR);
C   = cell(1, nA * nB);
iC  = 0;
for iA = 1:nA
    for iB = 1:nB
        iC    = iC + 1;
        C{iC} = repmat(A(iA,:), n, 1).' + (B(iB, :) - A(iA, :)).' * STR;
    end
end

As far as I can see, you can omit the repmat in Matlab >= 2016b.