import torch import torch.nn.functional as F def fused_linear_ce(X: torch.Tensor, W: torch.Tensor, B: torch.Tensor, targets: torch.Tensor) -> torch.Tensor: """ Baseline fused linear cross entropy implementation using PyTorch. Args: X: Input tensor of shape (M, K) - input features (float16) W: Weight tensor of shape (K, N) - weight matrix (float16) B: Bias tensor of shape (N,) - bias vector (float32) targets: Target tensor of shape (M,) - target class indices (int64) Returns: Output tensor of shape (M,) - negative log-likelihood loss per sample (float32) """ logits = (X @ W).float() + B.float() return F.cross_entropy(logits, targets, reduction='none')