[Discuss-gnuradio] Re: save date and value to an rotating file

[Markus Feldmann]

Josh Blum schrieb:

> There is a block called gr.head (misc->head) that shuts-off after N 
> samples pass through.
I mean to cut off the last line in the file and append the new data
to the file. But as i saw this is still a performance problem, however
it would work for me, because i do not save as much data to the file.

> and you can always add custom blocks that you write:
> http://gnuradio.org/trac/wiki/GNURadioCompanion#AddingCustomBlocks
But Custom Blocks rely on custom sinks and sources. I need to
process the data through an own python file sink method, with rotate
and time feature.
Or is this still possible ?
As i understood, processing of data is made in c++ and the
connection+gui is made in python.
> > There are many simple function not realized in grc like the 
> > mathematical root operation.
> >
> > Many doesn't work, and so you have to do many by hand !
>
> Anything that you can fit into a line of python is possible, so for 
> square root:
>
> 1)
> x**.5
Thanks for the hint.
But which grc modul apply this mathematical function on incoming data
and outputs it ?
I mean to apply mathematical function to incoming data from an Usrp
Source not a constant variable.
> 2)
> add an import block: import math
> math.sqrt(x)
Do you mean,
import math; math.sqrt(x)

In one line with a semicolon ?
Yes thats working. I still tested it.

Regards Markus