table having entries as points of elliptic curves

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Muhammad Sohail Abid 2018-7-3

0
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https://ww2.mathworks.cn/matlabcentral/answers/408495-table-having-entries-as-points-of-elliptic-curves

评论： Muhammad Sohail Abid 2018-7-3

I have 123387x2 arrays entries of elliptic curve points. I want to make a table of mxn order and also have to neglect the points having same x value, only take one point for each x-value

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KSSV 2018-7-3

How you are plotting ellipse?

Muhammad Sohail Abid 2018-7-3

在 MATLAB Online 中打开

if true
  % code
end
disp('y^2 = x^3 + 5376x + 2438 mod 123457')
a=0:123456
left_side = mod(a.^2,123457)
right_side = mod(a.^3+5376*a+2438,123457)
points = [];
for i = 1:length(right_side)
  I = find(left_side == right_side(i));
  for j=1:length(I)
      points = [points;a(i),a(I(j))];
  end
end
plot(points(:,1),points(:,2),'ro')
set(gca,'XTick',0:1:123456)
set(gca,'YTick',0:1:123456)
grid on;

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Answer 1

Mridul G 2018-7-3

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在 MATLAB Online 中打开

I assume you have 123387 (x,y) points, want to filter out points with the same x coordinate (pick one randomly for each x value), and then store it an appropriate table such that each cell contains an (x,y) tuple. You can first convert the matrix to a table, which would make life easier. The following might help:

mat = randi(100,100,2); %sample points
a = array2table(mat);
a = sortrows(a);
A = table2array(a);
[B, ia] = unique(A(:,1));
C = A(ia,2);
D = [B C];
%now you have your unique points, insert them into your m x n table as required