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qam: optimize decoding by vectorization

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Roman Zeyde
2014-09-21 17:23:52 +03:00
parent e9972c7ef2
commit 5264620183
1 changed files with 18 additions and 19 deletions
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37
amodem/qam.py
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@@ -3,6 +3,9 @@ from . import common
class QAM(object):
buf_size = 16
def __init__(self, symbols):
self._enc = {}
symbols = np.array(list(symbols))
@@ -33,28 +36,24 @@ class QAM(object):
s = S - self.bias
real_index = round(s.real * self.real_factor)
imag_index = round(s.imag * self.imag_factor)
self.symbols_map[real_index, imag_index] = (S, self._dec[S])
self.real_max = max(k[0] for k in self.symbols_map)
self.imag_max = max(k[1] for k in self.symbols_map)
self.symbols_map[real_index + 1j * imag_index] = (S, self._dec[S])
self.real_max = max(k.real for k in self.symbols_map)
self.imag_max = max(k.imag for k in self.symbols_map)
def encode(self, bits):
for _, bits_tuple in common.iterate(bits, self.bits_per_symbol, tuple):
for bits_tuple in common.iterate(bits, self.bits_per_symbol, tuple):
yield self._enc[bits_tuple]
def decode(self, symbols, error_handler=None):
real_factor = self.real_factor
imag_factor = self.imag_factor
real_max = self.real_max
imag_max = self.imag_max
bias = self.bias
symbols_map = self.symbols_map
for S in symbols:
s = S - bias
real_index = min(max(s.real * real_factor, 0), real_max)
imag_index = min(max(s.imag * imag_factor, 0), imag_max)
key = (round(real_index), round(imag_index))
decoded_symbol, bits = symbols_map[key]
if error_handler:
error_handler(received=S, decoded=decoded_symbol)
yield bits
for syms in common.iterate(symbols, self.buf_size, truncate=False):
s = syms - self.bias
real_index = np.clip(s.real * self.real_factor, 0, self.real_max)
imag_index = np.clip(s.imag * self.imag_factor, 0, self.imag_max)
keys = np.round(real_index + 1j * imag_index)
for key, received in zip(keys, syms):
decoded_symbol, bits = symbols_map[key]
if error_handler:
error_handler(received=received, decoded=decoded_symbol)
yield bits