> implemented on a GPP. For prototyping on GPPs Matlab or Gnu Radio.

Please, something libre - there's a cornucopia to choose from, from
GNU R to GNU Octave, Scilab and Sagemath.

https://www.gnu.org/software/octave/
https://en.wikipedia.org/wiki/GNU_Octave

https://www.r-project.org/
https://en.wikipedia.org/wiki/R_(programming_language)
https://rstudio.com/

https://opensource.com/alternatives/matlab

http://www.scilab.org/

http://www.sagemath.org/index.html

http://freemat.sourceforge.net/

http://www.jirka.org/genius.html

http://maxima.sourceforge.net/

http://www.numpy.org/
http://www.sympy.org/en/index.html

https://julialang.org/

...