utils.py 文件源码

def get_corrupted_input(rng, input, corruption_level, ntype='zeromask'):
    ''' depending on requirement, returns input corrupted by zeromask/gaussian/salt&pepper'''
    MRG = RNG_MRG.MRG_RandomStreams(rng.randint(2 ** 30))
    #theano_rng = RandomStreams()
    if corruption_level == 0.0:
        return input

    if ntype=='zeromask':
        return MRG.binomial(size=input.shape, n=1, p=1-corruption_level,dtype=theano.config.floatX) * input
    elif ntype=='gaussian':
        return input + MRG.normal(size = input.shape, avg = 0.0,
                std = corruption_level, dtype = theano.config.floatX)
    elif ntype=='salt_pepper':

        # salt and pepper noise
        print 'DAE uses salt and pepper noise'
        a = MRG.binomial(size=input.shape, n=1,\
                p=1-corruption_level,dtype=theano.config.floatX)
        b = MRG.binomial(size=input.shape, n=1,\
                p=corruption_level,dtype=theano.config.floatX)

        c = T.eq(a,0) * b
        return input * a + c