Can anyone please vectorize the code I have?

Input

J_org =

0 2 0 1 0 -1 -1

2 0 0 -1 -1 3 0

0 0 0 -2 0 1 1

1 -1 -2 0 2 0 0

0 -1 0 2 0 0 1

-1 3 1 0 0 0 0

-1 0 1 0 1 0 0

J_upper = triu(J_upper);

J_indices = [ 0 1 0 2 0 3 4

0 0 0 5 6 7 0

0 0 0 8 0 9 10

0 0 0 0 12 0 0

0 0 0 0 0 0 13

0 0 0 0 0 0 0

0 0 0 0 0 0 0]

Output:

J_out =[ 2 1 -1 -1 -1 -1 3 -2 1 1 0 2 1 0]

output J_out should be a flattened 1D vector where J_out(J_indices ) should be corresponding value from J_upper. If a J_index is missing (for example, 11 and 14 in my example), the value of that J_out will be zero. Length(J_out) should be ceil(0.5*length(J_org)*max(degree(graph(J_org)))). Here is my version of the code:

J_out  = zeros(1,ceil(0.5*length(J_org)*max(degree(graph(J_org)))));
for i = 1:length(J_org)
    for j =1:length(J_org)
        if J_indices(i,j)
            J_out (J_indices(i,j))= J_upper(i,j);
        end 
    end
end

Answer 1

[Bruno Luong]

There is nothing in your data to guess that Jout must have 14 elements, the last index > 0 is 13.

J_org = [
    0     2     0     1     0    -1    -1
    2     0     0    -1    -1     3     0
    0     0     0    -2     0     1     1
    1    -1    -2     0     2     0     0
    0    -1     0     2     0     0     1
    -1     3     1     0     0     0     0
    -1     0     1     0     1     0     0]

J_org = 7×7

0 2 0 1 0 -1 -1 2 0 0 -1 -1 3 0 0 0 0 -2 0 1 1 1 -1 -2 0 2 0 0 0 -1 0 2 0 0 1 -1 3 1 0 0 0 0 -1 0 1 0 1 0 0

J_upper = triu(J_org);
J_indices = [ 0     1     0     2     0     3     4
    0     0     0     5     6     7     0
    0     0     0     8     0     9    10
    0     0     0     0    12     0     0
    0     0     0     0     0     0    13
    0     0     0     0     0     0     0
    0     0     0     0     0     0     0]

J_indices = 7×7

0 1 0 2 0 3 4 0 0 0 5 6 7 0 0 0 0 8 0 9 10 0 0 0 0 12 0 0 0 0 0 0 0 0 13 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Jut=J_upper.';
Jit = J_indices.';
b=Jit>0;
Jout = zeros(1,14); % or J_out  = zeros(1,ceil(0.5*length(J_org)*max(degree(graph(J_org)))))
Jout(Jit(b)) = Jut(b)

Jout = 1×14

2 1 -1 -1 -1 -1 3 -2 1 1 0 2 1 0

[Nadatimuj]

@Bruno Luong Thanks for the quick answer. It's just a requirement for hardware purpose that the length of J_out must be an even number, although I agree it is invisible in the data. Thanks.

[Bruno Luong]

@Nadatimuj You are welcome, if it helps could you accept the answer?