boolean_mask_assign operator for future boolean indexing

src/operator/numpy/np_boolean_mask_assign.cc

@@ -0,0 +1,270 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*!
+ * \file np_boolean_assign.cc
+ * \brief CPU implementation of Boolean Mask Assign
+ */
+
+#include "../contrib/boolean_mask-inl.h"
+
+namespace mxnet {
+namespace op {
+
+template<bool scalar = false>
+struct BooleanAssignCPUKernel {
+ private:
+  static size_t bin_search(const size_t* idx,
+                           const size_t idx_size,
+                           const size_t i) {
+    size_t left = 0, right = idx_size, mid = (left + right) / 2;
+    while (left != right) {
+      if (idx[mid] == i + 1) {
+        if (idx[mid - 1] == i) {
+          mid -= 1;
+          break;
+        } else if (idx[mid - 1] == i + 1) {
+          right = mid;
+          mid = (left + right) / 2;
+        }
+      } else if (idx[mid] == i) {
+        if (idx[mid + 1] == i + 1) {
+          break;
+        } else {
+          left = mid;
+          mid = (left + right + 1) / 2;
+        }
+      } else if (idx[mid] < i + 1) {
+        left = mid;
+        mid = (left + right + 1) / 2;
+      } else if (idx[mid] > i + 1) {
+        right = mid;
+        mid = (left + right) / 2;
+      }
+    }
+    return mid;
+  }
+
+ public:
+  template<typename DType>
+  static void Map(int i,
+                  DType* data,
+                  const size_t* idx,
+                  const size_t idx_size,
+                  const size_t leading,
+                  const size_t middle,
+                  const size_t trailing,
+                  const DType val) {
+    // binary search for the turning point
+    size_t mid = bin_search(idx, idx_size, i);
+    // final answer is in mid
+    for (size_t l = 0; l < leading; ++l) {
+      for (size_t t = 0; t < trailing; ++t) {
+        data[(l * middle + mid) * trailing + t] = val;
+      }
+    }
+  }
+
+  template<typename DType>
+  static void Map(int i,
+                  DType* data,
+                  const size_t* idx,
+                  const size_t idx_size,
+                  const size_t leading,
+                  const size_t middle,
+                  const size_t trailing,
+                  DType* tensor) {
+    // binary search for the turning point
+    size_t mid = bin_search(idx, idx_size, i);
+    // final answer is in mid
+    for (size_t l = 0; l < leading; ++l) {
+      for (size_t t = 0; t < trailing; ++t) {
+        data[(l * middle + mid) * trailing + t] = (scalar) ? tensor[0] : tensor[i];
+      }
+    }
+  }
+};
+
+bool BooleanAssignShape(const nnvm::NodeAttrs& attrs,
+                        mxnet::ShapeVector *in_attrs,
+                        mxnet::ShapeVector *out_attrs) {
+  CHECK(in_attrs->size() == 2U || in_attrs->size() == 3U);
+  CHECK_EQ(out_attrs->size(), 1U);
+  const TShape& dshape = in_attrs->at(0);
+
+  // mask should have the same shape as the input
+  SHAPE_ASSIGN_CHECK(*in_attrs, 1, dshape);
+
+  // check if output shape is the same as the input data
+  SHAPE_ASSIGN_CHECK(*out_attrs, 0, dshape);
+
+  // for tensor version, the tensor should have less than 1 dimension
+  if (in_attrs->size() == 3U) {
+    CHECK_LE(in_attrs->at(2).ndim(), 1U)
+      << "boolean array indexing assignment requires a 0 or 1-dimensional input, input has "
+      << in_attrs->at(2).ndim() <<" dimensions";
+  }
+
+  return shape_is_known(out_attrs->at(0));
+}
+
+bool BooleanAssignType(const nnvm::NodeAttrs& attrs,
+                       std::vector<int> *in_attrs,
+                       std::vector<int> *out_attrs) {
+  CHECK(in_attrs->size() == 2U || in_attrs->size() == 3U);
+  CHECK_EQ(out_attrs->size(), 1U);
+
+  // input and output should always have the same type
+  TYPE_ASSIGN_CHECK(*out_attrs, 0, in_attrs->at(0));
+  TYPE_ASSIGN_CHECK(*in_attrs, 0, out_attrs->at(0));
+
+  if (in_attrs->size() == 3U) {
+    // if tensor version, the tensor should also have the same type as input
+    TYPE_ASSIGN_CHECK(*in_attrs, 2, in_attrs->at(0));
+    TYPE_ASSIGN_CHECK(*in_attrs, 0, in_attrs->at(2));
+    CHECK_NE(in_attrs->at(2), -1);
+  }
+
+  return out_attrs->at(0) != -1 && in_attrs->at(0) != -1 && in_attrs->at(1) != -1;
+}
+
+// calculate the number of valid (masked) values, also completing the prefix_sum vector
+template<typename DType>
+size_t GetValidNumCPU(const DType* idx, size_t* prefix_sum, const size_t idx_size) {
+  prefix_sum[0] = 0;
+  for (size_t i = 0; i < idx_size; i++) {
+    prefix_sum[i + 1] = prefix_sum[i] + ((idx[i]) ? 1 : 0);
+  }
+  return prefix_sum[idx_size];
+}
+
+void NumpyBooleanAssignForwardCPU(const nnvm::NodeAttrs& attrs,
+                                  const OpContext &ctx,
+                                  const std::vector<TBlob> &inputs,
+                                  const std::vector<OpReqType> &req,
+                                  const std::vector<TBlob> &outputs) {
+  using namespace mshadow;
+  using namespace mxnet_op;
+  CHECK(inputs.size() == 2U || inputs.size() == 3U);
+  CHECK_EQ(outputs.size(), 1U);
+  CHECK_EQ(req.size(), 1U);
+  CHECK_EQ(req[0], kWriteInplace)
+    << "Only WriteInplace is supported for npi_boolean_assign";
+
+  Stream<cpu>* s = ctx.get_stream<cpu>();
+
+  const TBlob& data = inputs[0];
+  const TBlob& mask = inputs[1];
+  // Get valid_num
+  size_t valid_num = 0;
+  size_t mask_size = mask.shape_.Size();
+  std::vector<size_t> prefix_sum(mask_size + 1, 0);
+  MSHADOW_TYPE_SWITCH(mask.type_flag_, MType, {
+    valid_num = GetValidNumCPU(mask.dptr<MType>(), prefix_sum.data(), mask_size);
+  });
+  // If there's no True in mask, return directly
+  if (valid_num == 0) return;
+
+  if (inputs.size() == 3U) {
+    if (inputs[2].shape_.Size() != 1) {
+      // tensor case, check tensor size with the valid_num
+      CHECK_EQ(static_cast<size_t>(valid_num), inputs[2].shape_.Size())
+        << "boolean array indexing assignment cannot assign " << inputs[2].shape_.Size()
+        << " input values to the " << valid_num << " output values where the mask is true"
+        << std::endl;
+    }
+  }
+
+  size_t leading = 1U;
+  size_t middle = mask_size;
+  size_t trailing = 1U;
+
+  if (inputs.size() == 3U) {
+    MSHADOW_TYPE_SWITCH(data.type_flag_, DType, {
+      if (inputs[2].shape_.Size() == 1) {
+        Kernel<BooleanAssignCPUKernel<true>, cpu>::Launch(
+          s, valid_num, data.dptr<DType>(), prefix_sum.data(), prefix_sum.size(),
+          leading, middle, trailing, inputs[2].dptr<DType>());
+      } else {
+       Kernel<BooleanAssignCPUKernel<false>, cpu>::Launch(
+          s, valid_num, data.dptr<DType>(), prefix_sum.data(), prefix_sum.size(),
+          leading, middle, trailing, inputs[2].dptr<DType>());
+      }
+    });
+  } else {
+    CHECK(attrs.dict.find("value") != attrs.dict.end())
+      << "value needs be provided";
+    MSHADOW_TYPE_SWITCH(data.type_flag_, DType, {
+      Kernel<BooleanAssignCPUKernel<true>, cpu>::Launch(
+        s, valid_num, data.dptr<DType>(), prefix_sum.data(), prefix_sum.size(),
+        leading, middle, trailing, static_cast<DType>(std::stod(attrs.dict.at("value"))));
+    });
+  }
+}
+
+NNVM_REGISTER_OP(_npi_boolean_mask_assign_scalar)
+.describe(R"code(Scalar version of boolean assign)code" ADD_FILELINE)
+.set_num_inputs(2)
+.set_num_outputs(1)
+.set_attr<nnvm::FListInputNames>("FListInputNames",
+  [](const NodeAttrs& attrs) {
+    return std::vector<std::string>{"data", "mask"};
+})
+.set_attr<mxnet::FInferShape>("FInferShape", BooleanAssignShape)
+.set_attr<nnvm::FInferType>("FInferType", BooleanAssignType)
+.set_attr<FCompute>("FCompute<cpu>", NumpyBooleanAssignForwardCPU)
+.set_attr<nnvm::FInplaceOption>("FInplaceOption",
+  [](const NodeAttrs& attrs) {
+    return std::vector<std::pair<int, int> >{{0, 0}};
+  })
+.set_attr<FResourceRequest>("FResourceRequest",
+  [](const NodeAttrs& attrs) {
+    return std::vector<ResourceRequest>{ResourceRequest::kTempSpace};
+  })
+.set_attr<nnvm::FGradient>("FGradient", MakeZeroGradNodes)
+.add_argument("data", "NDArray-or-Symbol", "input")
+.add_argument("mask", "NDArray-or-Symbol", "mask")
+.add_argument("value", "float", "value to be assigned to masked positions");
+
+NNVM_REGISTER_OP(_npi_boolean_mask_assign_tensor)
+.describe(R"code(Tensor version of boolean assign)code" ADD_FILELINE)
+.set_num_inputs(3)
+.set_num_outputs(1)
+.set_attr<nnvm::FListInputNames>("FListInputNames",
+  [](const NodeAttrs& attrs) {
+    return std::vector<std::string>{"data", "mask", "value"};
+})
+.set_attr<mxnet::FInferShape>("FInferShape", BooleanAssignShape)
+.set_attr<nnvm::FInferType>("FInferType", BooleanAssignType)
+.set_attr<FCompute>("FCompute<cpu>", NumpyBooleanAssignForwardCPU)
+.set_attr<nnvm::FInplaceOption>("FInplaceOption",
+  [](const NodeAttrs& attrs) {
+    return std::vector<std::pair<int, int> >{{0, 0}};
+  })
+.set_attr<FResourceRequest>("FResourceRequest",
+  [](const NodeAttrs& attrs) {
+    return std::vector<ResourceRequest>{ResourceRequest::kTempSpace};
+  })
+.set_attr<nnvm::FGradient>("FGradient", MakeZeroGradNodes)
+.add_argument("data", "NDArray-or-Symbol", "input")
+.add_argument("mask", "NDArray-or-Symbol", "mask")
+.add_argument("value", "NDArray-or-Symbol", "assignment");
+
+}  // namespace op
+}  // namespace mxnet