from random import random import torch import torch.nn as nn import torch.nn.functional as F from torch import einsum from models.arch_util import AttentionBlock from models.lucidrains.x_transformers import ContinuousTransformerWrapper, Encoder from trainer.networks import register_model from utils.util import opt_get, checkpoint def exists(val): return val is not None def masked_mean(t, mask): t = t.masked_fill(~mask, 0.) return t.sum(dim = 1) / mask.sum(dim = 1) class InfoNCE(nn.Module): """ Calculates the InfoNCE loss for self-supervised learning. This contrastive loss enforces the embeddings of similar (positive) samples to be close and those of different (negative) samples to be distant. A query embedding is compared with one positive key and with one or more negative keys. References: https://arxiv.org/abs/1807.03748v2 https://arxiv.org/abs/2010.05113 Args: temperature: Logits are divided by temperature before calculating the cross entropy. reduction: Reduction method applied to the output. Value must be one of ['none', 'sum', 'mean']. See torch.nn.functional.cross_entropy for more details about each option. negative_mode: Determines how the (optional) negative_keys are handled. Value must be one of ['paired', 'unpaired']. If 'paired', then each query sample is paired with a number of negative keys. Comparable to a triplet loss, but with multiple negatives per sample. If 'unpaired', then the set of negative keys are all unrelated to any positive key. Input shape: query: (N, D) Tensor with query samples (e.g. embeddings of the input). positive_key: (N, D) Tensor with positive samples (e.g. embeddings of augmented input). negative_keys (optional): Tensor with negative samples (e.g. embeddings of other inputs) If negative_mode = 'paired', then negative_keys is a (N, M, D) Tensor. If negative_mode = 'unpaired', then negative_keys is a (M, D) Tensor. If None, then the negative keys for a sample are the positive keys for the other samples. Returns: Value of the InfoNCE Loss. Examples: >>> loss = InfoNCE() >>> batch_size, num_negative, embedding_size = 32, 48, 128 >>> query = torch.randn(batch_size, embedding_size) >>> positive_key = torch.randn(batch_size, embedding_size) >>> negative_keys = torch.randn(num_negative, embedding_size) >>> output = loss(query, positive_key, negative_keys) """ def __init__(self, temperature=0.1, reduction='mean', negative_mode='unpaired'): super().__init__() self.temperature = temperature self.reduction = reduction self.negative_mode = negative_mode def forward(self, query, positive_key, negative_keys=None): return info_nce(query, positive_key, negative_keys, temperature=self.temperature, reduction=self.reduction, negative_mode=self.negative_mode) def info_nce(query, positive_key, negative_keys=None, temperature=0.1, reduction='mean', negative_mode='unpaired'): # Check input dimensionality. if query.dim() != 2: raise ValueError(' must have 2 dimensions.') if positive_key.dim() != 2: raise ValueError(' must have 2 dimensions.') if negative_keys is not None: if negative_mode == 'unpaired' and negative_keys.dim() != 2: raise ValueError(" must have 2 dimensions if == 'unpaired'.") if negative_mode == 'paired' and negative_keys.dim() != 3: raise ValueError(" must have 3 dimensions if == 'paired'.") # Check matching number of samples. if len(query) != len(positive_key): raise ValueError(' and must must have the same number of samples.') if negative_keys is not None: if negative_mode == 'paired' and len(query) != len(negative_keys): raise ValueError("If negative_mode == 'paired', then must have the same number of samples as .") # Embedding vectors should have same number of components. if query.shape[-1] != positive_key.shape[-1]: raise ValueError('Vectors of and should have the same number of components.') if negative_keys is not None: if query.shape[-1] != negative_keys.shape[-1]: raise ValueError('Vectors of and should have the same number of components.') # Normalize to unit vectors query, positive_key, negative_keys = normalize(query, positive_key, negative_keys) if negative_keys is not None: # Explicit negative keys # Cosine between positive pairs positive_logit = torch.sum(query * positive_key, dim=1, keepdim=True) if negative_mode == 'unpaired': # Cosine between all query-negative combinations negative_logits = query @ transpose(negative_keys) elif negative_mode == 'paired': query = query.unsqueeze(1) negative_logits = query @ transpose(negative_keys) negative_logits = negative_logits.squeeze(1) # First index in last dimension are the positive samples logits = torch.cat([positive_logit, negative_logits], dim=1) labels = torch.zeros(len(logits), dtype=torch.long, device=query.device) else: # Negative keys are implicitly off-diagonal positive keys. # Cosine between all combinations logits = query @ transpose(positive_key) # Positive keys are the entries on the diagonal labels = torch.arange(len(query), device=query.device) return F.cross_entropy(logits / temperature, labels, reduction=reduction) def transpose(x): return x.transpose(-2, -1) def normalize(*xs): return [None if x is None else F.normalize(x, dim=-1) for x in xs] class CollapsingTransformer(nn.Module): def __init__(self, model_dim, output_dims, heads, dropout, depth, mask_percentage=0, **encoder_kwargs): super().__init__() self.transformer = ContinuousTransformerWrapper( max_seq_len=-1, use_pos_emb=False, attn_layers=Encoder( dim=model_dim, depth=depth, heads=heads, ff_dropout=dropout, ff_mult=1, attn_dropout=dropout, use_rmsnorm=True, ff_glu=True, rotary_pos_emb=True, **encoder_kwargs, )) self.pre_combiner = nn.Sequential(nn.Conv1d(model_dim, output_dims, 1), AttentionBlock(output_dims, num_heads=heads, do_checkpoint=False), nn.Conv1d(output_dims, output_dims, 1)) self.mask_percentage = mask_percentage def forward(self, x, **transformer_kwargs): h = self.transformer(x, **transformer_kwargs) h = h.permute(0,2,1) h = checkpoint(self.pre_combiner, h).permute(0,2,1) if self.training: mask = torch.rand_like(h.float()) > self.mask_percentage else: mask = torch.ones_like(h.float()).bool() return masked_mean(h, mask) class ConvFormatEmbedding(nn.Module): def __init__(self, *args, **kwargs): super().__init__() self.emb = nn.Embedding(*args, **kwargs) def forward(self, x): y = self.emb(x) return y.permute(0,2,1) class ContrastiveAudio(nn.Module): def __init__( self, model_dim=512, transformer_heads=8, dropout=.1, encoder_depth=8, mel_channels=80, latent_multiplier=1, mask_percent=.15, ): super().__init__() latent_dim = latent_multiplier*model_dim self.temperature = nn.Parameter(torch.tensor(1.)) self.emb = nn.Sequential(nn.Conv1d(mel_channels, model_dim // 2, kernel_size=5, stride=2, padding=2), nn.Conv1d(model_dim//2, model_dim, kernel_size=3, stride=2, padding=1)) self.transformer = CollapsingTransformer(model_dim, model_dim, transformer_heads, dropout, encoder_depth, mask_percent) self.to_latent = nn.Linear(latent_dim, latent_dim, bias=False) self.to_latent2 = nn.Linear(latent_dim, latent_dim, bias=False) self.to_latent2.weight.data = self.to_latent.weight.data self.to_latent2.weight.DO_NOT_TRAIN = True self.to_latent2.requires_grad = False def get_grad_norm_parameter_groups(self): return { 'emb': list(self.emb.parameters()), 'xform': list(self.transformer.parameters()), } def update_for_step(self, step, __): self.to_latent2.weight.data = self.to_latent2.weight.data * .99 + self.to_latent.weight.data * .01 def forward( self, mel_input1, mel_input2 ): if len(mel_input2.shape) == 4: mel_input2 = mel_input2[:, 0] if self.training: # Mask out big chunks of separate frequency bands for each clip. b, c, _ = mel_input1.shape mask = torch.rand(b,c,1, device=mel_input1.device) > .3 mel_input1 = mask * mel_input1 * (1-random()*.5) mask = torch.rand(b,c,1, device=mel_input2.device) > .3 mel_input2 = mask * mel_input2 * (1-random()*.5) h1 = self.emb(mel_input1).permute(0, 2, 1) h1 = self.transformer(h1) h1 = self.to_latent(h1) h2 = self.emb(mel_input2).permute(0, 2, 1) h2 = self.transformer(h2) h2 = self.to_latent2(h2).detach() loss = info_nce(h1, h2) return loss @register_model def register_contrastive_audio(opt_net, opt): return ContrastiveAudio(**opt_get(opt_net, ['kwargs'], {})) if __name__ == '__main__': clvp = ContrastiveAudio() clvp(torch.randn(2,80,100), torch.randn(2,80,95), return_loss=True) v = torch.randn(2,512) print(info_nce(v,v))