Data manipulation within CELL

Hi all,

Please bear with my as I am using MATLAB only for 5 days now.

I work with some fatigue test data. From the given data I have managed to create a TABLE with all the relevant data needed (called AllStrains, TABLE of 607 rows(no. of Strain gauges) x 28514 columns (time steps of recorded data)).

For each row (Strain gauge) I have to brake the data into segments based on the loading Turning Point (Every load case of the Test has a unique ID name, when the load case change, this is a Turning Point). The segments have been identified in the variable Loading_Turn_Points (total number of Turn Points 844).

Based on the above Turning Points, I have managed to create, what I call, "windowstrains", which is segments of data from the AllStrains TABLE indexed based on the Turn_Points.

windowstrains is a CELL(843 x 1), where 843 is the number of Turning Points -1. Each CELL element is a TABLE (607 x K), where 607 is the number of Strain Gauges, and K varies.

From the "windowstrains" I am trying to identify the Strain Turning Points, in order to do so I came up with the following algorithm:

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1. Use diff() to create the difference of adjacent elms for each TABLE within the "windowstrains" CELL,

2. Then use sign()to get 1,0,-1 based o nthe diff().

3. Then use diff() again to get lots of zeros and 2,

4. Then I use find(), as the NON ZERO is my strain Turning point

5. Knowing the last, I should find the Time Step of the Strain Turning Point and compare it against the Loading Turnig Point, which I call it Lag.

6. Then I need the MODE of all the Lags (I should have 843 Lag values for each Strain Gauge, from which I need the MODE, and then 607 Lags (one for each Strain Gauge)).

7. Finally I need to save a csv file with 1 row and 2 columns. File name "fbin" and Lad (calculated above).

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Having describe what I need to do, my issues are:

1. I tried to do a LOOP:

%% Identify the Strains Turning Points per time window

for III=1:numel(Loading_Turn_Points)-1;

DiffDelta{III}=diff(windowstrains{III,1}(1,:));

end

But this ONLY gives my what I am after only for the first line (instead of 843 lines), when I tried to use the index III in this manner:

%% Identify the Strains Turning Points per time window

for III=1:numel(Loading_Turn_Points)-1;

DiffDelta{III}=diff(windowstrains{III,1}(III,:));

end

I get an ERROR "Attempted to access windowstrains.%cell(608,:); index out of bounds because size(windowstrains.%cell)=[607,25]."

I have tried to use the sign() for the DiffDelta CELL, but I get an ERROR "Undefined function 'sign' for input arguments of type 'cell'."

Any idea how to do the aforemention algorith in one loop?

2. Do you know how I can find the the Time Step of the Strain Turning Point? Step 5 in the algorithm

3. How do I save my calculated Lag in a CSV file?

4. Any general way of how to manipulated "nested" data within CELL in a TABLE format and how to use LOOP to populate CELLs and TABLEs, it would be great. I am a bit confused of CELL, TABLE definition when comes to coding.

Any help is welcome, thank you in advance.

Regards,

Yanis