ai.onnx.ConvTranspose

ai.onnx · standard ONNX operator · ONNX opset ≥ 11

Description

Computes the transpose of a convolution, also known as a fractionally strided convolution or deconvolution, from input tensor X, filter weights W, and an optional bias B. Output spatial dimensions follow the stride, dilation, padding, and optional output_padding attributes. Supports grouped convolution through group.

See the ONNX ConvTranspose spec for the reference semantics.

Inputs

Name Upstream name Logical dtype Rank Shape Description Presence
x X T — — Input data tensor of shape (N x C x D1 x ... x Dn), where N is batch size and C is the number of input channels. required
w W T — — Filter weight tensor of shape (C x M/group x k1 x ... x kn), where M is the number of output feature maps. required
bias B T 1 — Optional 1-D bias of length M added to each output channel. optional

Outputs

Name Upstream name Logical dtype Rank Shape Description Presence
y Y T same as x derived Output tensor whose spatial dimensions are computed from the input size, kernel shape, strides, dilations, and padding. required

Attributes

Attributes and default values (overridable per request):

Attribute Default Description
auto_pad "NOTSET" Padding mode: NOTSET uses explicit pads; SAME_UPPER and SAME_LOWER make output spatial size equal input size times stride, with any odd extra padding added at the end or beginning respectively; VALID applies no padding.
dilations — Dilation factors for each spatial axis; defaults to one on every axis.
group 1 Number of groups that input and output channels are divided into for grouped (depthwise) convolution.
kernel_shape — Kernel dimensions for each spatial axis. When omitted, they are inferred from the spatial dimensions of W.
output_padding — Additional size on the high-index end of each output spatial axis; each value must be smaller than the corresponding stride or dilation.
output_shape — Requested output spatial dimensions. When present, it must match the declared spatial shape of Y.
pads — Padding at the beginning of every spatial axis followed by padding at the end of every spatial axis; defaults to zeros.
strides — Stride factors for each spatial axis; defaults to one on every axis.

Type constraints

Variable Allowed dtypes
T float32, float16

Implementation variants

One implementation is selected per call from the device capabilities, the request shapes and the dtypes; these notes say what each one covers.

  • ncdhw3d_implicit_sgmat — Stride-1 transposed convolution as a forward convolution of the unchanged input with tap-reversed weights and begin pads of kernel-1-pad: the implicit-gather GEMM reads input windows directly and stores output elements directly, so no column matrix is materialized and no scatter pass runs, while the reduction spans the full in-channel-by-tap depth.
  • ncdhw3d_implicit_sgmat_bias — Stride-1 transposed convolution as a forward convolution of the unchanged input with tap-reversed weights and begin pads of kernel-1-pad: the implicit-gather GEMM reads input windows directly and stores output elements directly, so no column matrix is materialized and no scatter pass runs, while the reduction spans the full in-channel-by-tap depth.
  • nchw2d_grouped_stride_phase_blocked — Grouped stride-phase ConvTranspose where one invocation owns one output pixel and a block of that group's output channels: every gathered input sample feeds the whole block and the group's weight slab is staged once per workgroup. It serves grouped stride-two-or-more shapes whose per-group weights fit workgroup memory.
  • nchw2d_grouped_stride_phase_blocked_bias — Grouped stride-phase ConvTranspose where one invocation owns one output pixel and a block of that group's output channels: every gathered input sample feeds the whole block and the group's weight slab is staged once per workgroup. It serves grouped stride-two-or-more shapes whose per-group weights fit workgroup memory.

Device requirements

Some implementation variants require subgroup-matrix, shader-f16, and subgroups. These are route-specific capabilities, not package-wide requirements; availability also depends on the request shape and dtype.

Files

Use with @huggingface/kernels

npm install --save-exact @huggingface/kernels@0.0.1-preview.2

Required output shapes and logical data types are inferred from the supplied inputs and attributes; result tensors are allocated automatically.

The version: 1 option selects the published kernel contract; it is independent of any operator opset, contrib since_version, or model version. It follows the v1 branch as fixes land. To pin exact artifact bytes, pass a 40-character commit revision instead of version.

Replace each *Data placeholder with a typed array containing the corresponding input data.

import { getKernel } from "@huggingface/kernels";

const kernel = await getKernel("webgpu-kernels/ai.onnx.ConvTranspose", { version: 1 });
const { y } = await kernel({
  x: { data: xData, shape: [1, 1, 3] },
  w: { data: wData, shape: [1, 2, 2] },
});
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Requires WebGPU support. See the compatibility table.