Request help with .gwf file

Data Analysis
1

Hi Team,

I am finding difficulty in opening and reading .gwf files. Can someone help me with which application is used to open the file and if there is certain instructions to read the file?

-Ayush

2

Hello @Ayushg08,
I think @jonah answered your question in this thread. Normally in the frame of these workshops the read method should be enough to go through the tutorials and data challenge. This webpage could also give you additional information.

I hope to have answered your question.

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3

Hello @felix,
Yes, I think this will do the job. I will try to create the code with this insightful information. And, try to complete the data challenge.

Thank you.
-Ayush

4

I have a loosely-related question regarding the units of the data from the .gwf file. In our tutorials, the data was described as “dimensionless” whereas “unit: ct” appears in the output when we read the provided challenge files. Could you please tell us a little bit about this unit? Is this speed of light x time, to convert to units of length?

Thanks!

5

Hi Anna,

I have taken help from Day 3 tutorials. Please look into it, it will clear up most of your doubts. However, yes, it is with the unit: ct. But, when we are considering the case of coding a specific assignment, then we can modulate the values along with the dimensions. That is up to us, how we wish to modulate the code.

Regards,
Ayush

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6

@AnnaChrys_ip2i Strain is dimensionless - it is calibrated to a fractional change in length.

As a guess, I think ct refers to counts, which is a default label for dimensionless variables.

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7

Hi Ayush,

Thanks so much for your response, and the pointers!

All the best,
Anna

8

@jonah Ah, thanks so much for the clarification – that makes a lot more sense!

9

Yes, ct refers to counts; this is formally the number of counts recorded on an Analogue-to-Digital converter (ADC). This is how almost all data at the observatory are actually recorded.

In many cases the raw ‘counts’ are then calibrated back into physical units (typically something electrical like Voltage) which may instead be recorded in the GWF files.

This should be considered distinct from ‘dimensionless’, which is used for things like gravitational-wave strain.

However, at least in the past - this may still be true, I can’t remember - when a real physical unit was not manually configured by the observatory operations team, the data acquisition system (the thing that writes the GWF files in the first place) may insert ‘ct’ or ‘counts’ as the default, so all of the above information might not be absolutely applicable in practice.