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From: Jan Simon on 18 Feb 2010 16:21
Dear Mike!

> values = cell(50, 4);
> for i = 1:numberOfColons
> individualEvent = substr(compressedEvents, startOfEvent, (endi(i) - startOfEvent - 1));
> startOfEvent = endi(i);
> boxAndNeuron = substr(individualEvent, 0, 1);
> switch boxAndNeuron
> case '*' % v-- Box 1 --v
> box = 1;
> neuron = 1;
> case '+'
> box = 1;
> neuron = 2;
> case '\'
> box = 1;
> neuron = 3;
> case '-'
> box = 1;
> neuron = 4;
> case '.' % v-- Box 2 --v
> box = 2;
> neuron = 1;
> case '/'
> box = 2;
> neuron = 2;
> case '0'
> box = 2;
> neuron = 3;
> case '1'
> box = 2;
> neuron = 4;
> case '2' % v-- Box 3 --v
> box = 3;
> neuron = 1;
> case '3'
> box = 3;
> neuron = 2;
> case '4'
> box = 3;
> neuron = 3;
> case '5'
> box = 3;
> neuron = 4;
> case '6' % v-- Box 4 --v
> box = 4;
> neuron = 1;
> case '7'
> box = 4;
> neuron = 2;
> case '8'
> box = 4;
> neuron = 3;
> case '9'
> box = 4;
> neuron = 4;
> end
>
> channel = ((substr(individualEvent, 1, 1))-0) - 64;
> eventLength = length(individualEvent);
> timeStampSubstring = substr(individualEvent, 2);
> [endInteger] = regexp(timeStampSubstring,'[.]');
> integer = hex2dec(substr(timeStampSubstring, 0, (endInteger(1) - 1)));
> fraction = hex2dec(substr(timeStampSubstring, endInteger(1), (eventLength - endInteger(1))));
> timestamp = integer + (fraction / 1000000);
> values(i,:) = { box channel neuron timestamp };
> end
>
> decompressedArray = decompress(dataReceived);
> dataArray = cat(1, dataArray, decompressedArray);

> I need any empty rows at the end of the returned cell array to be removed before concatenating. I will look at teh current suggestions and see if they are what I need.

-------------------------------
Hmm - the code is not easy to read.

??? If you assign exactly [numberOfColons] rows, why not just create this number of cells?! Then you do not have to crop them finally.
values = cell(numberOfColons, 4);
for i = 1:numberOfColons
...

> values(i,:) = { box channel neuron timestamp };
I assume this to be faster - but please test this by your own:
values{i,1} = box;
values{i,2} = channel;
values{i,3} = neuron;
values{i,4} = timestamp;

> channel = ((substr(individualEvent, 1, 1))-0) - 64;
What is SUBSTR?! It would be nice to explain what you are posting.
If "substr(individualEvent, 0, 1)" means "individualEvent(1)" I'd definitely recommend the later. However, it can be simplified to:
channel = substr(individualEvent, 1, 1) - 64;

The switch expression is large. I'd expect something like this to be more efficient:
index = findstr(substr(individualEvent, 0, 1), '*+\-./0123456789');
box = ceil(index / 4);
neuron = mod(index - 1, 4) + 1;

> fraction = hex2dec(substr(timeStampSubstring, endInteger(1), (eventLength - endInteger(1))));

I expect sscanf(substr(timeStampSubstring, endInteger(1), (eventLength - endInteger(1))), '%x') to be faster.

Kind regards, Jan
From: Mike on 19 Feb 2010 12:01
It's often the simplest solution that gets overlooked. It never occurred to me that I know how many events I would have in my data based on the number of colons I found! I guess sometimes it takes a fresh pair of eyes.

Thank you for looking through my code and noticing that.

Regards,

Mike
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