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.