Re: [Discuss-gnuradio] Saving data

[Marcus Müller]

Hi Pedro,

that's what the file sink is for -- "sinking" data into files.
It's not producing a text file, because text files are pretty much a bad format for floating point values, usually, because you'd either be wasting enormous amounts of storage space to save each number in a textual format that tries as good as possible to represent the floating point value, or you'd lose accuracy. Either way, converting the in-memory binary floats to text is CPU-intense and therefore usually not done, unless you really know that you need it. Even then, it's pretty reasonable to argue that, yes, although
1.148842E-3+j1.888888E-1
1.488875E-4+j1.000000E-3
is human-readable, having a million of these lines (and that's how I read "a lot of samples" that you mention) makes the data de-facto unreadable, not even mentioning navigatable, without graphical aids.

Most people just import there samples later on e.g. into matlab -- but you wouldn't want to have textual numbers then, either (Matlab and Octave, as much as Python/numpy, and GNUplot can read binaries like the files produces by file sink directly).

That being said, you can actually pretty simply convert the binary files produced by file sink to text using python. For example, save the following as a text file and run it as "python <name_of_scriptfile> <input_samples.dat> <output_samples.txt>" (untested, since written for this mail only):

import numpy as np
from sys import argv
#complex64: 32bit float real, 32bit float imag
#float32: as name suggests
#int16: short int
format = np.complex64
data = "" dtype=format)
data.tofile(argv[2], sep='\n')

On 10/15/2015 08:54 PM, Pedro Gabriel Adami wrote:

Hello,

I have to sum a lot of samples. At the end of the flowgraph, I need to save the data I got in a file (not a .grc file) like a text one, for example. I need to see the values, because the graphical way will not present the information I need.

Please, do you know how to do this?

PS: if the sum results in 30, I need to store this value and the other ones that will come from the sum block.

Thanks in advance.

--

Atenciosamente,

Pedro Gabriel Adami

Graduando do 4º período de Engenharia de Controle e Automação no Inatel

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