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From: | Tim Huggins |
Subject: | Re: Problem initializing parameters in Gnuradio Python Block? |
Date: | Thu, 14 Jan 2021 17:07:22 +0000 (UTC) |
Hi Tim and Jeff,Thanks for your help and insights. Being new to Python, I was looking at some Python videos and found my solution, I will make the numpy parameter vectors in the my_init() method "global" and that should solve the problem.Thank you!Regards,GeorgeOn Thu, Jan 14, 2021 at 9:57 AM Tim Huggins <huggins.timothy@yahoo.com> wrote:George,"My understanding is the self.x, etc. is used to initialize param arguments in the def __init__() method and in my case, the only argument in this method is start"This is not correct, you can add a self.v in there so it looks like:def __init__(self, start = True): # only default arguments heregr.sync_block.__init__(
self,
name='text', # will show up in GRC
in_sig=[()],
out_sig=[()]
)
# if an attribute with the same name as a parameter is found,
# a callback is registered (properties work, too).
self.start = startself.v = self.my_init() #or whatever you want the initial value to beTimOn Thursday, January 14, 2021, 10:38:36 AM EST, George Edwards <gedwards.eng@gmail.com> wrote:Hi Jeff,So I am new to Python programming, so some of the nuances I am not up on yet. My understanding is the self.x, etc. is used to initialize param arguments in the def __init__() method and in my case, the only argument in this method is start, there is no v for me to use self.v = v. v is used the work() and my_init() methods. At program startup work() calls my_init() method to get the initial values for the numpy array v (my_init() function will be called once only at startup when self.start is True). After initialization and v is passed back to the work(), the values in the numpy array v inside work will change on a sample to sample computation basis. My problem is how do I assign v its initial seed value at start up. If my program was simple with only one parameter v, I would initialize it inside the work() method, however, I have a bunch of other vector variables to initialize which is why I want to initialize all parameters inside a my_init() method that work() calls at startup.Thanks for the help.GeorgeOn Thu, Jan 14, 2021 at 8:14 AM Jeff Long <willcode4@gmail.com> wrote:You are already initializing self.start in exactly the same way you should be initializing self.v, right?On Wed, Jan 13, 2021 at 10:46 PM George Edwards <gedwards.eng@gmail.com> wrote:Hi Jeff,Thanks for your answer. You are right, it crashes on the second call.So how do I write the program to initialize a bunch of vectors in a "method strictly for initialization" when it first starts running? If this cannot be done, then I guess the only solution is to initialize them in the work() method even though it would make the work() method bulky?Thanks again for your help.Regards,GeorgeOn Wed, Jan 13, 2021 at 8:12 PM Jeff Long <willcode4@gmail.com> wrote:'v' is a local variable in work(). It is probably crashing on the second call, where my_init() is not called, and thus there is no 'v'.On Wed, Jan 13, 2021 at 7:38 PM George Edwards <gedwards.eng@gmail.com> wrote:Hello,I am using a Gnuradio Python Block in my GRC signal processing and am having problems initializing my parameters. My system has a number of vector parameters to be initialized at startup. I will provide the gist of my goal in a scaled down version of my work.1. In the def __init__(self, start = True) method, "start" is the parameter that will be used in the program to run the initialization process and is set as follows:self.start = start2. In the work(self, input_items, output_items) method, I have the following at the start of the method:if self.start == True:v = self.my_init() # go initialize all vectorsoutput_items[0][:] = in0*v[0] + in1*v[1] + in2*v[2] #computation using v# with 3-inputs to the block3. In the my_init(self) method I have:self.start = False # set start to Falsev = np.array([1., 2., 3.]) #hypothetical to make this simplereturn vWhen I run the GRC model, it tells me that "v" is referenced before assignment. I am confused because I thought that the method my_init() would have been called before the computation and would return the values for "v". On the other hand if I do the assignment in the work(...) method as v = np.array([1., 2., 3.]), it works perfectly.Question: Why was the my_init() method not called properly to get the values for the numpy array v?Thanks for the help!Regards,George
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