MATLAB: Operate on Successive Values Without Loops

vectorization

Say I have a vector of x values, and a vector of y values. I would like to write a function to calculate the distance between successive points. I know how to do this in a loop, like the snippet given below.

for i = 1:1:size(x) - 1
    distance(i) = sqrt((x(i) - x(i + 1)) ^ 2 + (y(i) - y(i + 1)) ^ 2)
end

Is there a way to do this without the loop?

Best Answer

Totally... first arrange your vectors as column vectors, then try

distance = sum(sqrt((x(1:end-1)-x(2:end)).^2 + (y(1:end-1)-y(2:end)).^2),2);

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MATLAB: IF statement yields no output

Instead of this:

CHOICE(i) == (511 || 512)

you need this:

CHOICE(i)==511 || CHOICE(i)==512

Following the rules for operator precedence what you wrote is equivalent to:

CHOICE(i) == (511 || 512)
CHOICE(i) == True

which is likely to be False unless that value of CHOICE is 1 or True.

MATLAB: How to find if graph is connected

I think this is what you are looking for. The line with the variable 'con' is not really necessary, but if you need to reference the connections later it would be convenient.

R=0.3; %%radius
n = input('Enter number of nodes: ');
d=zeros(n,n);
con=zeros(n,n); % matrix of zeros indicates none are connected
x = rand(1,n);
y = rand(1,n);
plot(x,y,'o');
hold on
for i = 1 : (n)
    for j = 1 : (n)
      d(i, j) = sqrt((x(i) - x(j)) ^ 2 + (y(i) - y(j)) ^ 2); 
           if (d(i,j)<R)
               con(i,j)=1; % sets to 1 to indicate connection between node i and j
               hold on
               line([x(i), x(j)],[y(i), y(j)]);
           end
    end
end

Best Answer

Related Solutions

MATLAB: IF statement yields no output

MATLAB: How to find if graph is connected

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