Loop function in Matlab Programming - matlab

Question

I am trying to make a loop as below description in Matlab programming.
It likes two trees exploration.
Problem1:
I create a function with two input variables and output with four vars.
From originCoord(x,y,z) it creates two new coordinates R(x,y,z), L(x,y,z); (R means Right, L: left)
next R(x,y,z) -> new R1(x1,y1,z1) & L1(x1,y1,z1)
and L(x,y,z) -> new L2(x2,y2,z2) & R2(x2,y2,z2)
then to be continued
.....
loop will stop when one of the newCcoordinates() == targetCoordinates(xtarget, ytarget).
%from initial 3D point (x y z) using treeExploreation fuction to create two
%new3D points with coordinates (x1,y1,z1) and (x2,y2,z2)
%then from these new point, using this function two create new four 3D_Points...
%x y z are scala
rightPoint = [x1,y1,z1];
leftPoint = [x2,y2,z2];
targetPoint = [xtarget, ytarget, ztarget];
%store twop 3D points into coordExplore
coordExplore = [rightPoint,leftPoint];
temp = [];
flag = 0;
while (~flag)
for i=1:length(coordExplore)
[newrightPoint,newleftPoint]=treeExploration(coordExplore(i)); %help me at here !!!!
%this function with input (x,y,z) output two new coordinates i.e.
% newrightPoint(x3,y3,z3) and newleftPoint(x4,y4,z4)
if (newrightPoint==targetPoint) || (newleftPoint==targetPoint)
%this condition is to compare the output coordinates whether the same as
%the targetPoint
flag=1;
break;
else
temp =[newrightPoint,newleftPoint];
end
end
coordExplore = temp;
temp = [];
end
I got stuck when the output always greater than input. I cannot use all the output for the next loop.
Please help me to comment on how to make a loop for this case. Thanks.
Updated problems:
*I wish coordExplore(1) = rightPoint (x1 y1 z1)
and coordExplore(2) = leftPoint (x2 y2 z2)
BUT with index i=1, coordExplore(1) = x1; i=2 -> coordExplore(2) = y1;
I use the loop with coordExplore(i) in order to work from point-to-point within each point has its own coordinates(x y z). How can I do that?*
Problem2:
when one of the newCcoordinates() == targetCoordinates(xtarget, ytarget), how can I know which varibales in which direction from origin loop to last loop generating the result? (like which brands of the tree achieving the target).
In C++, I can use stack to save but in Matlab I do not know how can I save the variable for each loop.

Answer 1

Problem 1:
If I have understood what you want to achieve correctly, something like this should do the job.
reached_target = False;
coord = [x, y];
while ~reached_target
number_of_nodes = size(coord, 1)
new_coord = zeros(2*number_of_nodes)
for ii = 1:number_of_nodes
new_coord(ii*2-1, :) = doRightRunning(coord(ii, 1);
new_coord(ii*2, :) = doLeftRunning(coord(ii, 2);
end
target_ind = new_coord(:, 1) == x_target && new_coord(:, 2) == y_target;
if any(target_ind)
reached_target = True;
disp(find(target_ind));
end
end
However, the code you've shown doesn't match your explanations, so it's not clear if the next layer of the tree is 2 times or 4 times the size of the previous layer.
The code here basically calculates all the left and right runs for the current coordinates until the target is reached.
I haven't tested it yet, so look for bugs.
Problem 2:
It is not necessary to save the trail for knowing the turns it has made to reach the target. When a matching coordinate is found, its place in the list of coordinates reveal its trail. All you need to do is convert its index to binary and interpret 0 as right turn and 1 as left turn (since in the code, the right turn is placed on top, and the left turn on the bottom).
Example: Let's say we are in the 3rd layer of the tree with 8 coordinates and let's say the 6th coordinate matches the target. So starting from index 0, we have found a match at index which is 101 in binary format. It reveals that the turns to reach this coordinate are Left-Right-Left.