1// product-weight.h
2
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//     http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14//
15// Copyright 2005-2010 Google, Inc.
16// Author: riley@google.com (Michael Riley)
17//
18// \file
19// Product weight set and associated semiring operation definitions.
20
21#ifndef FST_LIB_PRODUCT_WEIGHT_H__
22#define FST_LIB_PRODUCT_WEIGHT_H__
23
24#include <stack>
25#include <string>
26
27#include <fst/pair-weight.h>
28#include <fst/weight.h>
29
30
31namespace fst {
32
33// Product semiring: W1 * W2
34template<class W1, class W2>
35class ProductWeight : public PairWeight<W1, W2> {
36 public:
37  using PairWeight<W1, W2>::Zero;
38  using PairWeight<W1, W2>::One;
39  using PairWeight<W1, W2>::NoWeight;
40  using PairWeight<W1, W2>::Quantize;
41  using PairWeight<W1, W2>::Reverse;
42
43  typedef ProductWeight<typename W1::ReverseWeight, typename W2::ReverseWeight>
44  ReverseWeight;
45
46  ProductWeight() {}
47
48  ProductWeight(const PairWeight<W1, W2>& w) : PairWeight<W1, W2>(w) {}
49
50  ProductWeight(W1 w1, W2 w2) : PairWeight<W1, W2>(w1, w2) {}
51
52  static const ProductWeight<W1, W2> &Zero() {
53    static const ProductWeight<W1, W2> zero(PairWeight<W1, W2>::Zero());
54    return zero;
55  }
56
57  static const ProductWeight<W1, W2> &One() {
58    static const ProductWeight<W1, W2> one(PairWeight<W1, W2>::One());
59    return one;
60  }
61
62  static const ProductWeight<W1, W2> &NoWeight() {
63    static const ProductWeight<W1, W2> no_weight(
64        PairWeight<W1, W2>::NoWeight());
65    return no_weight;
66  }
67
68  static const string &Type() {
69    static const string type = W1::Type() + "_X_" + W2::Type();
70    return type;
71  }
72
73  static uint64 Properties() {
74    uint64 props1 = W1::Properties();
75    uint64 props2 = W2::Properties();
76    return props1 & props2 & (kLeftSemiring | kRightSemiring |
77                              kCommutative | kIdempotent);
78  }
79
80  ProductWeight<W1, W2> Quantize(float delta = kDelta) const {
81    return PairWeight<W1, W2>::Quantize(delta);
82  }
83
84  ReverseWeight Reverse() const {
85    return PairWeight<W1, W2>::Reverse();
86  }
87
88
89};
90
91template <class W1, class W2>
92inline ProductWeight<W1, W2> Plus(const ProductWeight<W1, W2> &w,
93                                  const ProductWeight<W1, W2> &v) {
94  return ProductWeight<W1, W2>(Plus(w.Value1(), v.Value1()),
95                               Plus(w.Value2(), v.Value2()));
96}
97
98template <class W1, class W2>
99inline ProductWeight<W1, W2> Times(const ProductWeight<W1, W2> &w,
100                                   const ProductWeight<W1, W2> &v) {
101  return ProductWeight<W1, W2>(Times(w.Value1(), v.Value1()),
102                               Times(w.Value2(), v.Value2()));
103}
104
105template <class W1, class W2>
106inline ProductWeight<W1, W2> Divide(const ProductWeight<W1, W2> &w,
107                                    const ProductWeight<W1, W2> &v,
108                                    DivideType typ = DIVIDE_ANY) {
109  return ProductWeight<W1, W2>(Divide(w.Value1(), v.Value1(), typ),
110                               Divide(w.Value2(), v.Value2(), typ));
111}
112
113}  // namespace fst
114
115#endif  // FST_LIB_PRODUCT_WEIGHT_H__
116