[object Object][object Object][object Object]undefined[object Object]

• API function: Computes the attention backpropagation output in training scenarios, which is the backpropagation of . Compared with the API, this API has the [object Object] parameter added.

  • Ascend 950PR/Ascend 950DT: The softmaxInLayout parameter is not supported currently.
  • When the shape and actual data layout of the input [object Object] and [object Object] are TND, [object Object] must be set to [object Object].
  • When the shape of the input [object Object] and [object Object] is TND but the actual data layout is NTD, [object Object] must be set to [object Object].
  • In the original [object Object] API, the output format of [object Object] and [object Object] is NTD. The [object Object] API allows the input of the string parameter [object Object] to control whether to output [object Object] and [object Object] with both shape and data layout in TND format.

• Formula:

  The forward propagation formula for attention is as follows:

  $$Y=Dropout(Softmax(Mask(\frac{QK^T+pse}{\sqrt{d}}),atten\_mask),keep\_prob)V$$

  For convenience, the formula can be represented using variables $S$ and $P$:

  $$S=Mask(\frac{QK^T+pse}{\sqrt{d}}),atten\_mask$$ $$P=Dropout(Softmax(S),keep\_prob)$$ $$Y=PV$$

  Then the backward propagation formula for attention is as follows:

  $$dV=P^TdY$$ $$dQ=\frac{((dS)*K)}{\sqrt{d}}$$ $$dK=\frac{((dS)^T*Q)}{\sqrt{d}}$$

[object Object]

Each operator has calls. First, [object Object] is called to obtain the workspace size required for computation and the executor that contains the operator computation process. Then, [object Object] is called to perform computation.

[object Object]

• Parameters

  [object Object]

• Returns:

  [object Object]: status code. For details, see .

  The first-phase API implements input parameter verification. The following errors may be thrown.

  [object Object]

[object Object]

• Parameters

  [object Object]

• Returns:

  [object Object]: status code. For details, see .

[object Object]

• Deterministic computing:

  • [object Object] defaults to a non-deterministic implementation. You can call [object Object] to enable deterministic computing.

• When this API is used together with PyTorch, ensure that the CANN package versions match the PyTorch package versions.

• B (batch size) of the input [object Object], [object Object], [object Object], and [object Object] must be the same.

• The [object Object] of the input [object Object], [object Object], [object Object], and [object Object] must be the same.

• The input data types of [object Object], [object Object], [object Object], and [object Object] must be the same.

• The shapes of the input [object Object] and [object Object] must be the same. If the D values of [object Object], [object Object], and [object Object] are the same, the shapes of [object Object] and [object Object] must be the same. Note: In the current version, the D values of [object Object], [object Object], and [object Object] must be the same.

• N of the input [object Object] can be different from N of the [object Object] or [object Object], but they must be proportional. That is, Nq/Nkv must be a non-zero integer and the value of Nq ranges from 1 to 256.

• The following uses the [object Object] TND as an example to describe the constraints on the shape:

  • T(B*S): The value ranges from 1 to 1M.
  • B: The value ranges from 1 to 2K. When prefixOptional is carried, B supports a maximum of 1K.
  • N: The value ranges from 1 to 256.
  • S: The value ranges from 1 to 1M.
  • D: The value ranges from 1 to 768.
  • KeepProb: The value range is (0, 1].

• The data format of [object Object], [object Object], and [object Object] can only be TND. T indicates the data closely arranged on the B and S axes (SeqLenQ and SeqLenKV of each batch). B (Batch) indicates the batch size of the input sample, and S (Seq-Length) indicates the length of the input sample sequence. H (Head-Size) indicates the size of the hidden layer, N (Head-Num) indicates the number of heads. D (Head-Dim) indicates the minimum unit size of the hidden layer (D = H/N).

• pseShiftOptional: If Sq is greater than 1024, the sequence length of each batch is the same as that of Skv, and the sparseMode is 0, 2, or 3, the alibi positional encoding compression can be enabled. In this case, only the last 1024 rows of the original PSE need to be input for memory optimization. That is, alibi_compress = ori_pse[:, :, -1024:, :]. The details are as follows:

  • If the parameters of each batch are different, the shape is BNHSkv (H=1024).
  • When each batch is the same, the shape is 1NHSkv (H=1024).
  • If this parameter is not used, a null pointer can be passed.

• The constraints for [object Object] are as follows:

  • If the shape values of all [object Object] are the same and less than 2048, you are advised to use the default mode to reduce memory usage.
  • When this parameter is set to 1, 2, or 3, the configured preTokens and nextTokens do not take effect.
  • When the value is set to 0 or 4, ensure that the ranges of [object Object], [object Object], and [object Object] are consistent.
  • If no specific value is required, you are advised to set it to 0.
  • For details about the sparse modes, see .
  • When this parameter is set to 7, the optional input pseShiftOptional is not supported.

• In some scenarios, if the computation load is too large, the operator execution may time out (AI Core error, errorStr: timeout or trap error). In this case, you are advised to perform axis splitting. Note: The computation load is affected by parameters such as B, S, N, and D. Larger values indicate larger computation loads.

• The [object Object] sparse computing supports only compression scenarios ([object Object]). When Sq > Skv, the value range of N of [object Object] is [0, Skv]. When Sq ≤ Skv, the value range of N of [object Object] is [Skv – Sq, Skv].

• The [object Object] input supports the S length of 0 in a batch. In this case, the [object Object] input is not supported.

• Constraints on the [object Object] and [object Object] parameters: The input format is fixed at [B, N, S, 8], except TND format, which is [T, N, 8]. Note: T = B x S.

• The value of [object Object] must be the same as the value of N in [object Object].

• When the data layout of [object Object] and [object Object] is TND, [object Object] must be set to [object Object].

[object Object]

The following example is for reference only. For details, see .