Index exceeds the number of array elements. Index must not exceed 620757.

Question

Felicia DE CAPUA 2022-11-5

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1844013-index-exceeds-the-number-of-array-elements-index-must-not-exceed-620757

编辑： Torsten 2022-11-12

Hi everyone,

this is my code:

bin_data1 = 1:(bin*new_fs):size(data_1,1)-1;
time_1 = (1:bin:(size(data_1)/new_fs))-1;
step = data_1(bin_data1:bin_data1+(bin*new_fs)-1);
[S_1,f_1] = mtspectrumc(step,params);   % compute spectrum
value_data_1 = S_1(find((f_1>=2 & f_1<=150)==1));
value_data_1_smoothed=smoothdata(value_data_1,'gaussian',30);
value_data_1_smoothed_bin = value_data_1_smoothed(bin_data1);
plot(time_1,value_data_1_smoothed_bin,'r');
title('2-150 Hz'); xlable('Time (s)'); ylabel('Power (dB)');

When I do running the script, it appears a problem:

Index exceeds the number of array elements. Index must not exceed 620757.

But what is the index?

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Felicia DE CAPUA 2022-11-6

编辑：Image Analyst 2022-11-6

在 MATLAB Online 中打开

This is my script, the problem is the last part:

% to filter and downsample the LFP signal
new_fs = 1000; 
new_time = downsample(time,fs/new_fs);
Unrecognized function or variable 'time'.
movingwin = [10 5];  % set the moving
params.Fs = 1000;   % sampling frequency
params.fpass = [2 150];  % frequencies of interest
bin=30;                 % in seconds
params.tapers = [3 5];  % tapers
params.trialave = 0;   % average over trials
params.err = 0;    % no error computation
data_1 = LFP1_d; % data from monkeys 1
[S1,t,f1] = mtspecgramc(data_1,movingwin,params); % compute spectrogram
subplot(121)
plot_matrix(S1,t,f1);
xlabel('Time');
ylabel('Frequency'); % plot spectrogram
colorbar;
colormap('jet');
xmax = max(213.760);
xmin = min(546.740);
xline([xmax xmin],'--',{'r_M1'})
xmax = max(871.620);
xmin = min(1015.860);
xline([xmax xmin],'--',{'r'})
xmax = max(1048.520);
xmin = min(1170.800);
xline([xmax xmin],'--',{'s'})
data_2 = LFP2_d;    % data from monkeys 2
[S2,t,f2] = mtspecgramc(data_2,movingwin,params);  % compute spectrogram
subplot(122);
plot_matrix(S2,t,f2);
xlabel('Time'); % plot spectrogram
ylabel('Frequency');
colorbar;
colormap('jet');
xmax = max(213.760);
xmin = min(546.740);
xline([xmax xmin],'--',{'r_M1'})
xmax = max(871.620);
xmin = min(1015.860);
xline([xmax xmin],'--',{'r'})
xmax = max(1048.520);
xmin = min(1170.800);
xline([xmax xmin],'--',{'s'})
R_rest_1 = corrcoef(data_1(817.620:1015.860),data_2(817.620:1015.860));
R_rest_2 = corrcoef(data_1(1627.862:1751.560),data_2(1627.862:1751.560));
R_rest_3 = corrcoef(data_1(2413.580:2549.120),data_2(2413.580:2549.120));
R_stimulation_with_strobe_1 = corrcoef(data_1(1048.520:1170.800),data_2(1048.520:1170.800));
R_stimulation_with_strobe_2 = corrcoef(data_1(1786.080:1908.360),data_2(1786.080:1908.360));
R_stimulation_with_strobe_3 = corrcoef(data_1(2590.520:2703.260),data_2(2590.520:2703.260));
movingwin = [10 5];  % set the moving
params.Fs = 1000;   % sampling frequency
params.fpass = [2 150];  % frequencies of interest
params.tapers = [3 5];  % tapers
params.trialave = 0;   % average over trials
params.err = 0;    % no error computation
[S3,f3] = mtspectrumc(data_1,params);
subplot(121)
plot_vector(S3,f3);
xlabel('Frequency'); % plot spectrum
ylabel('Spectrum dB');
[S4,f4] = mtspectrumc(data_2,params);
subplot(122)
plot_vector(S4,f4);
xlabel('Frequency'); % plot spectrum
ylabel('Spectrum dB');
%%% Plot Power-Time of spectrum %%%
bin_data1 = 1:(bin*new_fs):size(data_1,1)-1;
data_1_smoothed = smoothdata(data_1,'gaussian',5);
value_1 = data_1_smoothed(bin_data1);
time_1 = (1:bin:(size(data_1)/new_fs))-1;
plot(time_1,value_1,'r');
title('LFP-Time'); xlabel('Time (s)');  ylabel('LFP');
hold on
bin_data2 = 1:(bin*new_fs):size(data_2,1)-1;
data_2_smoothed = smoothdata(data_2,'gaussian',5);
value_2 = data_2_smoothed(bin_data2);
time_2 = (1:bin:(size(data_2)/new_fs))-1;
plot(time_2,value_2,'b');
title('LFP-Time'); xlabel('Time (s)'); ylabel('LFP');
bin_data1 = 1:(bin*new_fs):size(data_1,1)-1;
time_1 = (1:bin:(size(data_1,1)/new_fs))-1;
step = data_1(bin_data1:bin_data1+(bin*new_fs)-1);
[S_1,f_1] = mtspectrumc(step,params);   % compute spectrum
value_data_1 = S_1(f_1>=2 & f_1<=150);
value_data_1_smoothed = smoothdata(value_data_1,'gaussian',5);
value_data1_smoothed = value_data_1_smoothed(bin_data1);
plot(time_1,value_data1_smoothed,'r');
title('2-150 Hz'); xlable('Time (s)'); ylabel('Power (dB)');

The problem is in the last part because I cannot to binning the value_data_1_smoothed because "Index must not exceed 4850. " The value data_1_smoothed is a vector 4850x1, while the bin_data1 are a vector 1x91.

Thank you so much for your help!

Jan 2022-11-8

编辑：Jan 2022-11-8

在 MATLAB Online 中打开

I've seen this line:

R_rest_1 = corrcoef(data_1(817.620:1015.860),data_2(817.620:1015.860));

This looks rather strange. Indices must have integer values. So this line should not run at all.

These lines are strange also:

xmax = max(213.760);  % ???
xmin = min(546.740);  % ??? Why?

Personally, I've lost the overview completely:

"I couldn't load the file because it is exceeds the dimension." - Which file do you want to load from where? Which dimensions are exceeded?
"I tried also in zip file" - what did you try?

I suggest to restart from scratch. Re-write the code. Create the values at first and move the visualization at the end. Then post some inputs, the relevant part of the code (omit the visualisation and the code behind the first error, becauce it is nor relevant to solve the problem) and a copy of the complete error message. Add meaningful comments in the code:

[S_1,f_1] = mtspectrumc(step,params); % compute spectrum

"compute spectrum" is not useful, because it does not add new information. That "mtspectrumc" computes a spectrum is more or less obvious. But what is the purpose of this line:

value_data_1 = S_1(f_1>=2 & f_1<=150);

How large is value_data_1 afterwards and what does it represent?

By the way, "value_data_1" is a bad choise for the name of a variable. The names "value_data_1_smoothed" and "value_data1_smoothed" cry for confusion also.

Focus on the failing part and post it in a way, which let the readers reproduce the error.

Jan 2022-11-11

@Torsten: Thanks for removing the misplaced comma from my comment.

As non-native speaker I'm aware that my spelling has a potential for improvements. I takes some time to check, what has been modified in an edited comment. Therefore I appreciate fixing typos, if it really improves the comprehensibility of my contributions.

Torsten 2022-11-12

编辑：Torsten 2022-11-12

@Jan

Thought I could do it unnoticed :-)

But although I'm from Germany (like you ?) where the comma in front of "that" is obligatory, it took some time before I understood what you meant in your comment. So I took the risk to edit away the comma.

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Answer 1

Steven Lord 2022-11-8

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1844013-index-exceeds-the-number-of-array-elements-index-must-not-exceed-620757#answer_1094213

在 MATLAB Online 中打开

What is element number 11 of the following vector?

x = 1:10

The answer to the question is "it doesn't exist." In situations where MATLAB asks that kind of question, the way it says "it doesn't exist" is to throw the error you're receiving.

To determine the root cause of this failure, set a breakpoint on the line of code where you receive this error then run your code. [If this code is in a loop and this error occurs only after a few iterations, set an error breakpoint as described in the Error Breakpoints section on that documentation page instead.] When MATLAB reaches the breakpoint, look at the size of the variable into which you're indexing and the max of the arrays you're using as indices.

Once you've confirmed that you're in this "asking for the 11th element of a 10 element vector" scenario, look backwards in your code to see where you're potentially changing the size or values of either of the arrays involved in that indexing operation. This could involve setting breakpoints on earlier lines of your code and stepping through line-by-line looking at those arrays in the Workspace Browser to detect when those arrays change.