Thanks! That worked. Here's a full working block:
"""
Embedded Python Blocks:
Each time this file is saved, GRC will instantiate the first class it finds
to get ports and parameters of your block. The arguments to __init__ will
be the parameters. All of them are required to have default values!
"""
import numpy as np
from gnuradio import gr
```
class blk(gr.sync_block): # other base classes are basic_block,
decim_block, interp_block
"""Embedded Python Block example - a simple multiply const"""
def __init__(self, example_param=1.0): # only default arguments here
"""arguments to this function show up as parameters in GRC"""
gr.sync_block.__init__(
self,
name='Embedded Python Block', # will show up in GRC
in_sig=[np.complex64],
out_sig=[np.complex64]
)
# if an attribute with the same name as a parameter is found,
# a callback is registered (properties work, too).
self.example_param = example_param
def work(self, input_items, output_items):
"""example: multiply with constant"""
output_items[0][:] = input_items[0] * self.example_param
return len(output_items[0])
@property
def example_param(self):
return self._example_param
@example_param.setter
def example_param(self, value):
print('here')
self._example_param = value
```
On Tue, Jun 25, 2024 at 8:33 AM Philipp Niedermayer <[email protected]>
wrote:
> As a workaround, use python's property construct to intercept changes on
> class attribute level:
>
> class blk(...):
> def __init__(self, example_param=1.0):
> ...
>
> # [...] (properties work, too)
> self.example_param = example_param
>
> @property
> def example_param(self):
> return self._example_param
>
> @example_param.setter
> def example_param(self, value):
> print('here')
> self._example_param = value
>
>
> ------------------------------
> *From:* Jameson Collins [mailto:[email protected]
> <[email protected]>]
> *Date:* Thursday, June 20, 2024 at 14:10 UTC+2
> *Subject:* Can Embedded Python Blocks have callbacks?
>
> This was my concern, and it does appear to behave that way.
>
> On Wed, Jun 19, 2024 at 4:34 PM Daniel Estévez <[email protected]>
> wrote:
>
>> On 19/06/2024 14:51, Jameson Collins wrote:
>> > I'm trying to use a callback to set a variable in an embedded python
>> > block. Using the tutorial
>> > (https://wiki.gnuradio.org/index.php/Embedded_Python_Block
>> > <https://wiki.gnuradio.org/index.php/Embedded_Python_Block>) as an
>> > example I added the function below. I've found that this callback
>> never
>> > gets called when I update this value from a GUI. Should it be?
>> >
>> > |def set_example_param(self, example_param): print("here")|
>>
>> Hi Jameson,
>>
>> I think Embedded Python blocks can only have (automatically generated)
>> callbacks for __init__() arguments that are assigned as
>>
>> self.foo = foo
>>
>> in the body of __init__() (the example template that you get when you
>> create a new Embedded Python block shows how this works).
>>
>> If you need more complex callbacks, I think you need to create a regular
>> Python block in an OOT module.
>>
>> Best,
>> Daniel.
>>
>>
>>
