compute event rate and plot histogram

I have 606,774(1st row means event no.1)events and 11 column data among them 9th column is the 64-bit absolute time of trigger in unix time(accurate to microsecond), I need help to compute events rate by using time stamps and make plot of event rate using mtlab. The time stamps for only 2 event is like,

1388557138250759

1388557138255312

Answer 1

[dpb]

W/o a lot more effort, you'll lose some precision w/ Matlab datenum but for human consumption it may be sufficient.

>> tun=[1388557138250759
        1388557138255312];
>> datestr(tun/86400/1000/1000 + datenum(1970,1,1),'ddmmmyyyy hh:MM:ss.fff')
ans =
01Jan2014 06:18:58.251
01Jan2014 06:18:58.255
>> diff(tun)
ans =
      4553
>>

Gives the delta-t in microseconds for a sampled timeseries which you can scale as desired.

[Chiranjibi]

Thanks, but I have 606,774 events each events has different time. Above two time stamp is only for two events. So can you please help me to calculate event rate for all events.

[dpb]

diff(t)

where t is your input column vector.

Answer 2

[José-Luis]

If your want to get Matlab serial date number and you don't care about leap seconds, then you could do:

 tun=int64([1388557138250759
        1388557138255312]);
 epoch = datenum(1970,1,1);
 numDays = double(tun ./ int64(86400 * 10^6));
 remainder = double(mod(tun , int64(86400*10^6))) ./ (10^6*86400);
 datevec(epoch +  numDays + remainder )

[Chiranjibi]

Thanks, but I have 606,774 events each events has different time. Above two time stamp is only for two events. So can you please help me to calculate event rate for all events.

[José-Luis]

Well, the variable tun can be made to be any size you want. So you have to import the data first.

[Chiranjibi]

Actually this is for data analysis of nuclear detector. Please take a look this attached file, I able to identify broken channels for all events from column 1-8 (stretcher value. So now I need to compute event rate from this time stamp (9th column is time in microsecond).

[José-Luis]

 tun = int64(strVals(:,9));
 epoch = datenum(1970,1,1);
 numDays = double(tun ./ int64(86400 * 10^6));
 remainder = double(mod(tun , int64(86400*10^6))) ./ (10^6*86400);
 datevec(epoch +  numDays + remainder )

[Chiranjibi]

Is that gives us event rate ?is it necessary to use numDays/datevec.... only for event rate?

[José-Luis]

How do you calculate the event rate?

[Chiranjibi]

I have no idea, that's why I'm asking you. Although I got only 6 column from above code.

[José-Luis]

Yes, but what is the formula for it? What do you want? How many times a given time stamp occurs? How do you define when two events are equal? You need that to calculate a rate.