view swig/python/test.py @ 214:f28f66faa016

Add "stateful" feature type with initial feature "last n"

Stateful feature extraction functions are functions that require state to be maintained between successive calls.  This is necessary, for example when an accumulation of values is required, or changes need to be measured over time.

The initial xtract_last_n() function accumulates the last N (single) values from *data and writes them to *result

#!/usr/bin/python

try:
    import libxtract.xtract as xtract
except ImportError:
    print 'Failed to load the library "xtract"'

print '\nRunning libxtract Python bindings test...\n'

len = 8

a = xtract.doubleArray(len)
temp = []

for i in range(0, len):
    a[i] = 2 * i
    temp.append(str(a[i]))

mean = xtract.xtract_mean(a,len,None)[1]

print 'The mean of ' + ', '.join(temp) + ' is: %.2f' % mean

argv = xtract.doubleArray(1)
argv[0] = mean

variance = xtract.xtract_variance(a, len, argv)[1]

print 'The variance is %.2f' % variance

print 'Computing spectrum...'

argv = xtract.doubleArray(1)
argv[0] = 44100.0 / len  # Fake sample rate

xtract.xtract_init_fft(len, xtract.XTRACT_SPECTRUM);

result = xtract.doubleArray(len)

xtract.xtract_spectrum(a,len,argv, result)


for i in range(len):
    print result[i]


print 'Computing windowed subframes...'

for i in range(0, len):
    a[i] = 1.0

window = xtract.xtract_init_window(len / 2, xtract.XTRACT_HANN)
xtract.xtract_features_from_subframes(a, len, xtract.XTRACT_WINDOWED, window, result) 

for i in range(len):
    print result[i]

print '\nFinished!\n'