converting timestamps.npy in matlab

[Judith Schweimer]

Hello,

I have an issue when I convert the timestamps.npy in matlab.

The conversion itself works fine, using the npy to matlab script on GitHub ('https://github.com/kwikteam/npy-matlab').

This produces an array of increasing integers in int64. If I then divide these by the sampling rate, I again get an integer, which is the correct value, but obviously has no decimals being an integer.

Is there a way to convert the int64 into a number that shows the decimals within matlab? I have tried several options like double, but they don't give me the expected value anymore.

Any advice is appreciated,

Judith

[Davidson, Tom]

You need to cast the int to double before the division:

timestamp = int64(3000)

samplerate = 30000  % will be of type double by default 

ans1 = timestamp ./ samplerate % returns an int64 with value 0

ans2 = double(timestamp) ./ samplerate % returns a double with value 0.1

% if you convert ans1 to double after the division, the fractional information has already been lost to rounding

double(ans1) % returns a double with value 0

See this page for a discussion of this behavior by Matlab:

https://www.mathworks.com/help/matlab/matlab_prog/integers.html

"Arithmetic operations that involve both integers and floating-point always result in an integer data type."

Best,

Tom

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[Judith Schweimer]

Thanks, Tom! that worked!

I used a wrong way trying to convert the integers.