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meyer_wavelet

Bases: discrete_wavelet

Source code in tinybig/koala/signal_processing/wavelet.py 
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class meyer_wavelet(discrete_wavelet):
    def __init__(self, name: str = 'meyer_wavelet', *args, **kwargs):
        super().__init__(name=name, *args, **kwargs)

    def psi(self, tau: torch.Tensor):
        result = torch.zeros_like(tau)

        zero_mask = (tau == 0)
        result[zero_mask] = 2.0/3.0 + 4.0/(3.0 * torch.pi)

        nonzero_mask = ~zero_mask
        t_nonzero = tau[nonzero_mask]
        result[nonzero_mask] = (
            (torch.sin((2.0 * torch.pi / 3.0) * t_nonzero) +
             4.0/3.0 * t_nonzero * torch.cos((4.0 * torch.pi / 3.0) * t_nonzero)) /
            (torch.pi * t_nonzero - (16.0 * torch.pi / 9.0) * t_nonzero ** 3)
        )
        return result