ONNX: GatherElements, Xor (#2568)

candle-onnx/src/eval.rs

@@ -670,6 +670,49 @@ fn simple_eval_(
                 };
                 values.insert(node.output[0].clone(), xs);
             }
+            // https://onnx.ai/onnx/operators/onnx__GatherElements.html#gatherelements
+            // A Note to fellow lurkers:
+            // The numpy based `gather_elements` implementation in `onnx` tests [here](https://github.com/onnx/onnx/blob/main/onnx/backend/test/case/node/gatherelements.py)
+            // and examples is incorrect.
+            // Use `torch.gather` for the validating/ verifying against the proper behaviour
+            "GatherElements" => {
+                let data = get(&node.input[0])?;
+                let indices = get(&node.input[1])?;
+
+                let rank = data.rank();
+                if rank != indices.rank() {
+                    bail!("indices must have same rank as input data. Data rank [{}] != indices rank [{}]", data.rank(), indices.rank());
+                }
+
+                let axis = {
+                    let axis_i64 = get_attr_opt::<i64>(node, "axis")?.copied().unwrap_or(0);
+                    let axis = data.normalize_axis(axis_i64)?;
+
+                    if axis >= rank {
+                        bail!(
+                            "axis ({}) out of accepted range [-rank, rank-1] which was [-{rank}, {}]",
+                            axis_i64,
+                            rank - 1
+                        )
+                    }
+
+                    axis
+                };
+
+                // index_select does not support negative indices, so normalize them
+                // to positive indices.
+                let indices = &{
+                    let zeros = Tensor::zeros(indices.shape(), indices.dtype(), indices.device())?;
+                    let max = Tensor::new(data.dims()[axis] as i64, indices.device())?
+                        .to_dtype(indices.dtype())?;
+                    let mask = indices.lt(&zeros)?;
+                    mask.to_dtype(indices.dtype())?
+                        .broadcast_mul(&max)?
+                        .add(indices)?
+                };
+
+                values.insert(node.output[0].clone(), data.gather(indices, axis)?);
+            }
             "Shape" => {
                 // https://github.com/onnx/onnx/blob/main/docs/Operators.md#Shape
                 let xs = get(&node.input[0])?;
@@ -1891,6 +1934,16 @@ fn simple_eval_(
                     );
                 }
             }
+            // https://onnx.ai/onnx/operators/onnx__Xor.html
+            "Xor" => {
+                // Since we don't have a `DType::Bool` yet, this ensures that we are working with `0`(False) & `1`(True)
+                let a = get(&node.input[0])?.gt(0_u8)?;
+                let b = get(&node.input[1])?.gt(0_u8)?;
+
+                let out = a.broadcast_add(&b)?.eq(1_u8)?;
+
+                values.insert(node.output[0].clone(), out);
+            }
             op_type => bail!("unsupported op_type {op_type} for op {node:?}"),
         }
     }