|
|
| import torch |
| import custom_ctc_cpp |
|
|
| Tensor = torch.Tensor |
|
|
| class CustomCTCLossFunction(torch.autograd.Function): |
| @staticmethod |
| def forward( |
| ctx, |
| log_probs: Tensor, |
| targets: Tensor, |
| realval: Tensor, |
| targets_realval: Tensor, |
| input_lengths: Tensor, |
| target_lengths: Tensor, |
| sigma: float = 1, |
| blank: int = 0, |
| blank1: int = 0, |
| reduction: str = "mean", |
| zero_infinity: bool = False |
| ): |
| assert reduction in ['none', 'mean'] |
| if isinstance(input_lengths, list) : |
| input_lengths = Tensor(input_lengths).long().to(log_probs.device) |
| if isinstance(target_lengths, list) : |
| target_lengths = Tensor(target_lengths).long().to(log_probs.device) |
| neg_log_likelihood, log_alpha = custom_ctc_cpp.forward(log_probs, targets, realval, targets_realval, input_lengths, target_lengths, sigma, blank, blank1, zero_infinity) |
| ctx.save_for_backward(neg_log_likelihood, log_alpha, log_probs, targets, realval, targets_realval, input_lengths, target_lengths) |
| ctx.blank = blank |
| ctx.blank1 = blank1 |
| ctx.zero_infinity = zero_infinity |
| ctx.sigma = sigma |
| ctx.reduction = reduction |
| if reduction == 'mean' : |
| return (neg_log_likelihood / target_lengths.clamp_min(1)).mean() |
| return neg_log_likelihood |
|
|
| @staticmethod |
| def backward(ctx, grad_out): |
| neg_log_likelihood, log_alpha, log_probs, targets, realval, targets_realval, input_lengths, target_lengths = ctx.saved_tensors |
| if ctx.reduction == 'mean' : |
| if grad_out.numel() == 0 : |
| grad_out = torch.ones_like(neg_log_likelihood) |
| else : |
| grad_out = grad_out.view(1).tile(neg_log_likelihood.size(0)) |
| grad_out /= target_lengths.clamp_min(1) |
| grad_out /= log_probs.size(0) |
| outputs_cls, outputs_realval = custom_ctc_cpp.backward(grad_out, log_probs, targets, realval, targets_realval, input_lengths, target_lengths, neg_log_likelihood, log_alpha, ctx.sigma, ctx.blank, ctx.blank1, ctx.zero_infinity) |
| return outputs_cls, None, outputs_realval, None, None, None, None, None, None, None, None |
|
|
