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Python function

flash_attention_gpu

flash_attention_gpu()

max.experimental.nn.common_layers.functional_kernels.flash_attention_gpu(q, k, v, mask_variant, scale, local_window_size=-1, valid_length=None)

source

Computes flash attention using a GPU-optimized kernel.

Parameters:

• q (TensorValue) – The query tensor, of shape [batch, seq_len, num_heads, head_dim].
• k (TensorValue) – The key tensor, of shape [batch, seq_len, num_heads, head_dim].
• v (TensorValue) – The value tensor, of shape [batch, seq_len, num_heads, head_dim].
• mask_variant (MHAMaskVariant) – The mask variant to use for attention.
• scale (float) – The scaling factor for attention scores.
• local_window_size (int) – The local window size for sliding window attention.
• valid_length (TensorValue | None) – The optional tensor of shape [batch] with dtype uint32. When provided, uses the padded kernel variant that respects the valid sequence lengths for each batch element.

Returns:

The output tensor, of shape [batch, seq_len, num_heads, head_dim].

Return type:

Tensor