Complex Numbers in Matrices

My program loop generates 60

N(i,1) = [complex #1; complex #2; complex #3; complex #4], 

Here, all the complex numbers are different. Each N has two complex numbers with positive imaginary part and two with negative imaginary part.

I need to isolate two complex numbers with positive imaginary part. And store this complex number in

Matrix1= First accepted Complex Number with positive imaginary part

Matrix2= Second accepted Complex Number with positive imaginary part.

Such that both Matrix 1 and 2, should have 60 complex number each obtained from N.

Answer 1

[Walter Roberson]

format short
%create some data that has the required characteristics
N = complex(rand(4,60), rand(4,60));
for K = 1 : 60; c = randperm(4,2); N(c,K) = conj(N(c,K)); end

%now process
Matrix1 = N(sub2ind(size(N), sum(cumprod(imag(N) < 0))+1, 1:size(N,2)));
Matrix2 = N(sub2ind(size(N), sum(cumprod(imag(N) > 0))+1, 1:size(N,2)));

%and check.
disp(N(:,1:3))

   0.2657 - 0.7314i   0.2445 - 0.5625i   0.4933 - 0.9174i
   0.9369 - 0.1687i   0.9194 + 0.6287i   0.9663 + 0.5250i
   0.7501 + 0.2729i   0.6338 - 0.9384i   0.8267 + 0.3453i
   0.2002 + 0.2955i   0.5082 + 0.0311i   0.8804 - 0.3498i

disp(Matrix1(1:3))

   0.7501 + 0.2729i   0.9194 + 0.6287i   0.9663 + 0.5250i

disp(Matrix2(1:3))

   0.2657 - 0.7314i   0.2445 - 0.5625i   0.4933 - 0.9174i

%the below is not relevant to the code you wanted. I happened to notice a display bug
%so I am using the below as part of a report to Mathworks.
N(:,1:4)

ans = 4×4

0.2657 - 0.7314i 0.2445 - 0.5625i 0.4933 - 0.9174i 0.7601 - 0.6164i 0.9369 - 0.1687i 0.9194 + 0.6287i 0.9663 + 0.5250i 0.8809 - 0.8984i 0.7501 + 0.2729i 0.6338 - 0.9384i 0.8267 + 0.3453i 0.1348 + 0.8749i 0.2002 + 0.2955i 0.5082 + 0.0311i 0.8804 - 0.3498i 0.8497 + 0.7985i

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N(:,1:5)

ans = 4×5

0.2657 - 0.7314i 0.2445 - 0.5625i 0.4933 - 0.9174i 0.7601 - 0.6164i 0.8942 - 0.4792i 0.9369 - 0.1687i 0.9194 + 0.6287i 0.9663 + 0.5250i 0.8809 - 0.8984i 0.9630 + 0.9265i 0.7501 + 0.2729i 0.6338 - 0.9384i 0.8267 + 0.3453i 0.1348 + 0.8749i 0.1853 + 0.2537i 0.2002 + 0.2955i 0.5082 + 0.0311i 0.8804 - 0.3498i 0.8497 + 0.7985i 0.7903 - 0.6989i

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N(1:10)

ans = 1×10

0.2657 - 0.7314i 0.9369 - 0.1687i 0.7501 + 0.2729i 0.2002 + 0.2955i 0.2445 - 0.5625i 0.9194 + 0.6287i 0.6338 - 0.9384i 0.5082 + 0.0311i 0.4933 - 0.9174i 0.9663 + 0.5250i

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