index_map.h

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 * 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
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#ifndef TVM_TIR_INDEX_MAP_H_
#define TVM_TIR_INDEX_MAP_H_

#include <tvm/ir/expr.h>
#include <tvm/runtime/container/array.h>
#include <tvm/runtime/object.h>
#include <tvm/tir/var.h>

#include <utility>

namespace tvm {
namespace arith {
class Analyzer;
}
}  // namespace tvm

namespace tvm {
namespace tir {

class IndexMapNode : public Object {
 public:
  Array<Var> initial_indices;

  Array<PrimExpr> final_indices;

  Optional<ObjectRef> inverse_index_map;

  IndexMapNode() {}

  Array<PrimExpr> MapIndices(const Array<PrimExpr>& indices,
                             arith::Analyzer* analyzer = nullptr) const;

  Array<Range> MapRanges(const Array<Range>& ranges, arith::Analyzer* analyzer = nullptr) const;

  Array<PrimExpr> MapShape(const Array<PrimExpr>& shape, arith::Analyzer* analyzer = nullptr) const;

  /* \brief Map an NDArray according to this index map
   *
   * \param arr_src The NDArray whose layout is transformed by this index map.
   *
   * \returns The transformed NDArray.
   */
  runtime::NDArray MapNDArray(runtime::NDArray arr_src) const;

  String ToPythonString(
      const std::function<Optional<String>(const Var& var)>& f_name_map = nullptr) const;

  void VisitAttrs(AttrVisitor* v) {
    v->Visit("initial_indices", &initial_indices);
    v->Visit("final_indices", &final_indices);
    v->Visit("inverse_index_map", &inverse_index_map);
  }

  bool SEqualReduce(const IndexMapNode* other, SEqualReducer equal) const {
    return equal.DefEqual(initial_indices, other->initial_indices) &&
           equal(final_indices, other->final_indices);
  }

  void SHashReduce(SHashReducer hash_reduce) const {
    hash_reduce.DefHash(initial_indices);
    hash_reduce(final_indices);
  }

  static constexpr const char* _type_key = "tir.IndexMap";
  static constexpr const bool _type_has_method_sequal_reduce = true;
  static constexpr const bool _type_has_method_shash_reduce = true;
  TVM_DECLARE_FINAL_OBJECT_INFO(IndexMapNode, Object);
};

class IndexMap : public ObjectRef {
 public:
  IndexMap(Array<Var> initial_indices, Array<PrimExpr> final_indices,
           Optional<IndexMap> inverse_index_map = NullOpt);

  static IndexMap FromFunc(int ndim, runtime::TypedPackedFunc<Array<PrimExpr>(Array<Var>)> func,
                           Optional<IndexMap> inverse_index_map = NullOpt);

  IndexMap Inverse(Array<Range> initial_ranges) const;

  IndexMap RenameVariables(
      const std::function<Optional<String>(const Var& var)>& f_name_map = nullptr) const;

  std::pair<IndexMap, PrimExpr> NonSurjectiveInverse(Array<Range> initial_ranges) const;

  TVM_DEFINE_OBJECT_REF_METHODS(IndexMap, ObjectRef, IndexMapNode);
};

IndexMap Substitute(const IndexMap& index_map,
                    std::function<Optional<PrimExpr>(const Var& var)> f_subst);

}  // namespace tir
}  // namespace tvm

#endif  // TVM_TIR_INDEX_MAP_H_