Index exceeds the number of array elements. Index must not exceed 0.

Now I make code which estimate Correlation dimension．But ,error happed

「 Index exceeds the number of array elements. Index must not exceed 0.

error: Distance (column 27) if MinDist(j) > minval(j)

error: CorrDim (column 35) [Radius] = Distance(xnew, Nopoints)」

A function named 'Distance' is affecting the error. How to fix it? Which matrix index do I need to consider?

load('trajectory.mat')

X = x2;                    % load data

MaxEmDim = 3;
TimeDelay = 2;

%% Reconstraction by timedelay embdding
%% Portrait = Reconstraction trajectory, NoPoints = Nomber of points each dimension, MaxPosEmDim
[Portrait_X, Nopoints_X, MaxPosEmDim_X] =Trajectory(X, MaxEmDim, TimeDelay); %

Unrecognized function or variable 'Trajectory'.

%% draw atracttor
figure(1)
plot(Portrait_X(:,3),Portrait_X(:,1),'bo','MarkerFaceColor','b','MarkerSize',5)
grid on

%% Calculation of correlation dimension

xnew = Portrait_X; % n×3 matrix 

% number opf valid points in xnew matrix

Nopoints = [size(xnew)*[1;0] size(xnew)*[1;0] size(xnew)*[1;0]];

% caluculates 32 equi-spaced bins on a logarithmic scale

[Radius] = Distance(xnew, Nopoints); %% error happend●●


%% function caluculates distances point to point
% Radius is the matrix{32,MaxEmDim} in which the difference between the
% maximum and minimum distances from one point to any other, is diveded
% into 32 logarithmically equal intervals (for any dimensions)

% Portrait is trajectory data, Nopoints is vector in which  the number of
% valid points for each dimensions
function [Radius] = Distance(Portrait, NoPoints)

         MaxEmDim = size(Portrait) *[0;1];  
         NoPointsEnd = [NoPoints 1];
         MinDist = ones(1, MaxEmDim)*1e20;  
         MaxDist = zeros(1, MaxEmDim);      
         Radius = zeros(32, MaxEmDim);      

         for EmDim = 1:MaxEmDim
             minval  = zeros(1, EmDim);
             minloc  = zeros(1, EmDim);
             maxval  = zeros(1, EmDim);
             maxloc  = zeros(1, EmDim);

             for i=NoPointsEnd(EmDim):-1:NoPointsEnd(EmDim+1)+1
                 Distances = DistVectPoint(Portrait(1:1-1,1:EmDim), Portrait(i, 1:EmDim));

                 DistanceNoZero = ElimZero(Distances, 1e-10);
                 [minval, mincol] = min(DistanceNoZero,[],1);
                 [maxval, maxloc] = max(Distances, [], 1);

                 for j=1:EmDim
                     if MinDist(j) > minval(j) %%●● here is involved error 
                         MinDist(j) = minval(j);
                     end

                     if MaxDist(j) < maxval(j)
                         MaxDist(j) = maxval(j);
                     end
                 end
             end
         end

         for k=1:32
             Radius(k,:) = exp(log(MinDist) + k*(log(MaxDist) - log(MinDist))/32);
         end
end

Answer 1

[Jan]

This is strange:

MaxEmDim = size(Portrait) *[0;1];
Nopoints = [size(xnew)*[1;0] size(xnew)*[1;0] size(xnew)*[1;0]]

Use size(X, 1) and size(X, 2) instead.

The line:

if MinDist(j) > minval(j)

fails, if minval or MinDist is empty. You have to catch this exception explicitly.

[ryunosuke tazawa]

First ,Nopoints is the score in each dimension and has been changed as follows.

Nopoints = [size(X,1) size(X,2) size(X,3)] %[484 482 480]

How should I explicitly catch the exception?

Should I change the value of the following value (1e20)?

MinDist = ones(1, MaxEmDim)*1e20;