# TensorRT Custom Ops
- [TensorRT Custom Ops](#tensorrt-custom-ops)
- [MMCVRoIAlign](#mmcvroialign)
- [Description](#description)
- [Parameters](#parameters)
- [Inputs](#inputs)
- [Outputs](#outputs)
- [Type Constraints](#type-constraints)
- [ScatterND](#scatternd)
- [Description](#description-1)
- [Parameters](#parameters-1)
- [Inputs](#inputs-1)
- [Outputs](#outputs-1)
- [Type Constraints](#type-constraints-1)
- [NonMaxSuppression](#nonmaxsuppression)
- [Description](#description-2)
- [Parameters](#parameters-2)
- [Inputs](#inputs-2)
- [Outputs](#outputs-2)
- [Type Constraints](#type-constraints-2)
- [MMCVDeformConv2d](#mmcvdeformconv2d)
- [Description](#description-3)
- [Parameters](#parameters-3)
- [Inputs](#inputs-3)
- [Outputs](#outputs-3)
- [Type Constraints](#type-constraints-3)
- [grid_sampler](#grid_sampler)
- [Description](#description-4)
- [Parameters](#parameters-4)
- [Inputs](#inputs-4)
- [Outputs](#outputs-4)
- [Type Constraints](#type-constraints-4)
## MMCVRoIAlign
### Description
Perform RoIAlign on output feature, used in bbox_head of most two stage
detectors.
### Parameters
| Type | Parameter | Description |
| ------- | ---------------- | ------------------------------------------------------------------------------------------------------------- |
| `int` | `output_height` | height of output roi |
| `int` | `output_width` | width of output roi |
| `float` | `spatial_scale` | used to scale the input boxes |
| `int` | `sampling_ratio` | number of input samples to take for each output sample. `0` means to take samples densely for current models. |
| `str` | `mode` | pooling mode in each bin. `avg` or `max` |
| `int` | `aligned` | If `aligned=0`, use the legacy implementation in MMDetection. Else, align the results more perfectly. |
### Inputs
- inputs[0]: T
- Input feature map; 4D tensor of shape (N, C, H, W), where N is the batch size, C is the numbers of channels, H and W are the height and width of the data.
- inputs[1]: T
- RoIs (Regions of Interest) to pool over; 2-D tensor of shape (num_rois, 5) given as [[batch_index, x1, y1, x2, y2], ...]. The RoIs' coordinates are the coordinate system of inputs[0].
### Outputs
- outputs[0]: T
- RoI pooled output, 4-D tensor of shape (num_rois, C, output_height, output_width). The r-th batch element output[0][r-1] is a pooled feature map corresponding to the r-th RoI inputs[1][r-1].
-
### Type Constraints
- T:tensor(float32, Linear)
## ScatterND
### Description
ScatterND takes three inputs `data` tensor of rank r >= 1, `indices` tensor of rank q >= 1, and `updates` tensor of rank q + r - indices.shape[-1] - 1. The output of the operation is produced by creating a copy of the input `data`, and then updating its value to values specified by updates at specific index positions specified by `indices`. Its output shape is the same as the shape of `data`. Note that `indices` should not have duplicate entries. That is, two or more updates for the same index-location is not supported.
The `output` is calculated via the following equation:
```python
output = np.copy(data)
update_indices = indices.shape[:-1]
for idx in np.ndindex(update_indices):
output[indices[idx]] = updates[idx]
```
### Parameters
None
### Inputs
- inputs[0]: T
- Tensor of rank r>=1.
- inputs[1]: tensor(int32, Linear)
- Tensor of rank q>=1.
- inputs[2]: T
- Tensor of rank q + r - indices_shape[-1] - 1.
### Outputs
- outputs[0]: T
- Tensor of rank r >= 1.
### Type Constraints
- T:tensor(float32, Linear), tensor(int32, Linear)
## NonMaxSuppression
### Description
Filter out boxes has high IoU overlap with previously selected boxes or low score. Output the indices of valid boxes. Indices of invalid boxes will be filled with -1.
### Parameters
| Type | Parameter | Description |
| ------- | ---------------------------- | ------------------------------------------------------------------------------------------------------------------------------------ |
| `int` | `center_point_box` | 0 - the box data is supplied as [y1, x1, y2, x2], 1-the box data is supplied as [x_center, y_center, width, height]. |
| `int` | `max_output_boxes_per_class` | The maximum number of boxes to be selected per batch per class. Default to 0, number of output boxes equal to number of input boxes. |
| `float` | `iou_threshold` | The threshold for deciding whether boxes overlap too much with respect to IoU. Value range [0, 1]. Default to 0. |
| `float` | `score_threshold` | The threshold for deciding when to remove boxes based on score. |
| `int` | `offset` | 0 or 1, boxes' width or height is (x2 - x1 + offset). |
### Inputs
- inputs[0]: T
- Input boxes. 3-D tensor of shape (num_batches, spatial_dimension, 4).
- inputs[1]: T
- Input scores. 3-D tensor of shape (num_batches, num_classes, spatial_dimension).
### Outputs
- outputs[0]: tensor(int32, Linear)
- Selected indices. 2-D tensor of shape (num_selected_indices, 3) as [[batch_index, class_index, box_index], ...].
- num_selected_indices=num_batches* num_classes* min(max_output_boxes_per_class, spatial_dimension).
- All invalid indices will be filled with -1.
### Type Constraints
- T:tensor(float32, Linear)
## MMCVDeformConv2d
### Description
Perform Deformable Convolution on input feature, read [Deformable Convolutional Network](https://arxiv.org/abs/1703.06211) for detail.
### Parameters
| Type | Parameter | Description |
| -------------- | ------------------ | --------------------------------------------------------------------------------------------------------------------------------- |
| `list of ints` | `stride` | The stride of the convolving kernel. (sH, sW) |
| `list of ints` | `padding` | Paddings on both sides of the input. (padH, padW) |
| `list of ints` | `dilation` | The spacing between kernel elements. (dH, dW) |
| `int` | `deformable_group` | Groups of deformable offset. |
| `int` | `group` | Split input into groups. `input_channel` should be divisible by the number of groups. |
| `int` | `im2col_step` | DeformableConv2d use im2col to compute convolution. im2col_step is used to split input and offset, reduce memory usage of column. |
### Inputs
- inputs[0]: T
- Input feature; 4-D tensor of shape (N, C, inH, inW), where N is the batch size, C is the numbers of channels, inH and inW are the height and width of the data.
- inputs[1]: T
- Input offset; 4-D tensor of shape (N, deformable_group* 2* kH* kW, outH, outW), where kH and kW is the height and width of weight, outH and outW is the height and width of offset and output.
- inputs[2]: T
- Input weight; 4-D tensor of shape (output_channel, input_channel, kH, kW).
### Outputs
- outputs[0]: T
- Output feature; 4-D tensor of shape (N, output_channel, outH, outW).
### Type Constraints
- T:tensor(float32, Linear)
## grid_sampler
### Description
Perform sample from `input` with pixel locations from `grid`.
### Parameters
| Type | Parameter | Description |
| ----- | -------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `int` | `interpolation_mode` | Interpolation mode to calculate output values. (0: `bilinear` , 1: `nearest`) |
| `int` | `padding_mode` | Padding mode for outside grid values. (0: `zeros`, 1: `border`, 2: `reflection`) |
| `int` | `align_corners` | If `align_corners=1`, the extrema (`-1` and `1`) are considered as referring to the center points of the input's corner pixels. If `align_corners=0`, they are instead considered as referring to the corner points of the input's corner pixels, making the sampling more resolution agnostic. |
### Inputs
- inputs[0]: T
- Input feature; 4-D tensor of shape (N, C, inH, inW), where N is the batch size, C is the numbers of channels, inH and inW are the height and width of the data.
- inputs[1]: T
- Input offset; 4-D tensor of shape (N, outH, outW, 2), where outH and outW is the height and width of offset and output.
### Outputs
- outputs[0]: T
- Output feature; 4-D tensor of shape (N, C, outH, outW).
### Type Constraints
- T:tensor(float32, Linear)