pyPhix 0.1

Description:

pyPhix 0.1

pyPhix, the Python Fixed Point module
pyPhix is a python package for fixed point number representation.
It is intended to support the implementation of digital signal processing systems.
As such only fix-point addition, subtraction and multiplication operations are implemented.
You can find more information about the module objects and functionalities at
readthedocs project page.
Features

virtually unlimited number length (depending on your RAM size)
based on NumPy
customizable rounding method (SymInf, SymZero, NonSymPos,
NonSymNeg, ConvEven, ConvOdd, Floor, Ceil)
customizable wrapping method (Sat, Wrap)
support various representation formats (bin, hex, int, float)
perform single or array based operations with customizable output format (+, -, *)

License
pyPhix
pyPhix is an open source python module released under the terms of
Mozilla Public License Version 2.0.
NumPy
NumPy is the fundamental package needed for scientific computing with Python and it is released under these
terms.
Install
The pyPhix package is available on pypi.org.
You can install it by running:
$ pip install pyphix.
Alternatively you can clone the pyPhix repository and from the folder containing the setup.py file run:
$ python setup install
This package requires Python 3.6 to work.
You can also directly download the tar.gz archive from pypi.org.
The archive can be easily verified by adding the gpg public key
1E948096166391C0
to your keyring.
Usage Examples
Fix Format
This object is used to indicate the number of bits the user wants to use for value reprensetation.
Create fix-point format objets:
>>> from pyphix import fix
>>> fmt_a=fix.FixFmt(True, 2, 10)
>>> fmt_b=fix.FixFmt(False, 0, 7)

Print the maximum representable ranges and test if a value is included in the range:
>>> fmt_a.fixrange
(-4.0, 3.9990234375)

>>> fmt_b.fixrange
(0.0, 0.9921875)

>>> -10 in fmt_a
False

>>> 0 in fmt_b
True

Different representations are available:
>>> fmt_a.tuplefmt
(True, 2, 10)

>>> fmt_b.listfmt
[False, 0, 7]

>>> print(fmt_b)
(False, 0, 7)

Fix Number
This object contain fix-point number represenation.
Round methods comparison, assuming format (True, 4, 5):



Round method
Pos odd fraction
Pos even fraction
Neg odd fraction
Neg even fraction




Real value
7.296875
2.325
-1.078125
-1.08125


Mult by 2^5
233.5
74.4
-34.5
-34.6


SymInf
7.3125
2.3125
-1.09375
-1.09375


SymZero
7.28125
2.3125
-1.0625
-1.09375


NonSymPos
7.3125
2.3125
-1.0625
-1.09375


NonSymNeg
7.28125
2.3125
-1.09375
-1.09375


ConvEven
7.3125
2.3125
-1.0625
-1.09375


ConvOdd
7.28125
2.3125
-1.09375
-1.09375


Floor
7.28125
2.3125
-1.09375
-1.09375


Ceil
7.3125
2.34375
-1.0625
-1.0625



A small usage example:
>>> from pyphix import fix
>>> from pyphix.fix import ERoundMethod, EOverMethod
>>> fmt = fix.FixFmt(True, 4, 5)
>>> fix_vec = fix.FixNum(
[7.296875, 2.325 , -1.078125, -1.08125], fmt,
rnd=ERoundMethod.CONV_ODD, over=EOverMethod.WRAP)
>>> fix_val = fix.FixNum(
1.16, fmt,
rnd=ERoundMethod.CONV_ODD, over=EOverMethod.WRAP)

Perform a full resolution addition:
>>> fix_vec + fix_val
[8.4375 3.46875 0.0625 0.0625 ]

fmt: (True, 5, 5)
rnd: ERoundMethod.CONV_ODD
over: EOverMethod.WRAP

Perform a multiplication and cast result to a small format:
>>> fix_val.mult(
fix_vec, out_fmt=fix.FixFmt(False, 3, 2),
rnd=ERoundMethod.SYM_INF, over=EOverMethod.SAT)
[7.75 2.75 0. 0. ]

fmt: (False, 3, 2)
rnd: ERoundMethod.SYM_INF
over: EOverMethod.SAT