import argparse import numpy as np import torch import glob from captum._utils.common import _get_module_from_name # compute rollout between attention layers def compute_rollout_attention(all_layer_matrices, start_layer=0): # adding residual consideration- code adapted from https://github.com/samiraabnar/attention_flow num_tokens = all_layer_matrices[0].shape[1] batch_size = all_layer_matrices[0].shape[0] eye = torch.eye(num_tokens).expand(batch_size, num_tokens, num_tokens).to(all_layer_matrices[0].device) all_layer_matrices = [all_layer_matrices[i] + eye for i in range(len(all_layer_matrices))] matrices_aug = [all_layer_matrices[i] / all_layer_matrices[i].sum(dim=-1, keepdim=True) for i in range(len(all_layer_matrices))] joint_attention = matrices_aug[start_layer] for i in range(start_layer+1, len(matrices_aug)): joint_attention = matrices_aug[i].bmm(joint_attention) return joint_attention class Generator: def __init__(self, model, key="bert.encoder.layer"): self.model = model self.key = key self.model.eval() def forward(self, input_ids, attention_mask): return self.model(input_ids, attention_mask) def _calculate_gradients(self, output, index, do_relprop=True): if index == None: index = np.argmax(output.cpu().data.numpy(), axis=-1) one_hot_vector = (torch.nn.functional .one_hot( # one_hot requires ints torch.tensor(index, dtype=torch.int64), num_classes=output.size(-1) ) # but requires_grad_ needs floats .to(torch.float) ).to(output.device) hot_output = torch.sum(one_hot_vector.clone().requires_grad_(True) * output) self.model.zero_grad() hot_output.backward(retain_graph=True) if do_relprop: return self.model.relprop(one_hot_vector, alpha=1) def generate_LRP(self, input_ids, attention_mask, index=None, start_layer=11): output = self.model(input_ids=input_ids, attention_mask=attention_mask)[0] if index == None: index = np.argmax(output.cpu().data.numpy(), axis=-1) self._calculate_gradients(output, index) cams = [] blocks = _get_module_from_name(self.model, self.key) for blk in blocks: grad = blk.attention.self.get_attn_gradients() cam = blk.attention.self.get_attn_cam() cam = cam[0].reshape(-1, cam.shape[-1], cam.shape[-1]) grad = grad[0].reshape(-1, grad.shape[-1], grad.shape[-1]) cam = grad * cam cam = cam.clamp(min=0).mean(dim=0) cams.append(cam.unsqueeze(0)) rollout = compute_rollout_attention(cams, start_layer=start_layer) rollout[:, 0, 0] = rollout[:, 0].min() return rollout[:, 0] def generate_LRP_last_layer(self, input_ids, attention_mask, index=None): output = self.model(input_ids=input_ids, attention_mask=attention_mask)[0] if index == None: index = np.argmax(output.cpu().data.numpy(), axis=-1) self._calculate_gradients(output, index) cam = _get_module_from_name(self.model, self.key)[-1].attention.self.get_attn_cam()[0] cam = cam.clamp(min=0).mean(dim=0).unsqueeze(0) cam[:, 0, 0] = 0 return cam[:, 0] def generate_full_lrp(self, input_ids, attention_mask, index=None): output = self.model(input_ids=input_ids, attention_mask=attention_mask)[0] if index == None: index = np.argmax(output.cpu().data.numpy(), axis=-1) cam = self._calculate_gradients(output, index) cam = cam.sum(dim=2) cam[:, 0] = 0 return cam def generate_attn_last_layer(self, input_ids, attention_mask, index=None): output = self.model(input_ids=input_ids, attention_mask=attention_mask)[0] cam = _get_module_from_name(self.model, self.key)[-1].attention.self.get_attn()[0] cam = cam.mean(dim=0).unsqueeze(0) cam[:, 0, 0] = 0 return cam[:, 0] def generate_rollout(self, input_ids, attention_mask, start_layer=0, index=None): self.model.zero_grad() output = self.model(input_ids=input_ids, attention_mask=attention_mask)[0] blocks = _get_module_from_name(self.model, self.key) all_layer_attentions = [] for blk in blocks: attn_heads = blk.attention.self.get_attn() avg_heads = (attn_heads.sum(dim=1) / attn_heads.shape[1]).detach() all_layer_attentions.append(avg_heads) rollout = compute_rollout_attention(all_layer_attentions, start_layer=start_layer) rollout[:, 0, 0] = 0 return rollout[:, 0] def generate_attn_gradcam(self, input_ids, attention_mask, index=None): output = self.model(input_ids=input_ids, attention_mask=attention_mask)[0] if index == None: index = np.argmax(output.cpu().data.numpy(), axis=-1) self._calculate_gradients(output, index) cam = _get_module_from_name(self.model, self.key)[-1].attention.self.get_attn() grad = _get_module_from_name(self.model, self.key)[-1].attention.self.get_attn_gradients() cam = cam[0].reshape(-1, cam.shape[-1], cam.shape[-1]) grad = grad[0].reshape(-1, grad.shape[-1], grad.shape[-1]) grad = grad.mean(dim=[1, 2], keepdim=True) cam = (cam * grad).mean(0).clamp(min=0).unsqueeze(0) cam = (cam - cam.min()) / (cam.max() - cam.min()) cam[:, 0, 0] = 0 return cam[:, 0] def generate_rollout_attn_gradcam(self, input_ids, attention_mask, index=None, start_layer=0): # rule 5 from paper def avg_heads(cam, grad): return (grad * cam).clamp(min=0).mean(dim=-3) # rule 6 from paper def apply_self_attention_rules(R_ss, cam_ss): return torch.matmul(cam_ss, R_ss) output = self.model(input_ids=input_ids, attention_mask=attention_mask)[0] blocks = _get_module_from_name(self.model, self.key) num_tokens = input_ids.size(-1) R = torch.eye(num_tokens).expand(output.size(0), -1, -1).clone().to(output.device) for i, blk in enumerate(model.roberta.encoder.layer): if i < start_layer: continue grad = blk.attention.self.get_attn_gradients().detach() cam = blk.attention.self.get_attn().detach() cam = avg_heads(cam, grad) joint = apply_self_attention_rules(R, cam) R += joint return R[:, 0, 1:-1]