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MueLu_ParameterListInterpreter.cpp
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4//
5// MueLu: A package for multigrid based preconditioning
6// Copyright 2012 Sandia Corporation
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46
47#include <cstring>
48#include <string>
49#include <vector>
50#include <algorithm>
51
52namespace MueLu {
53
54 size_t LevenshteinDistance(const char* s, size_t len_s, const char* t, size_t len_t) {
55 // degenerate cases
56 if (len_s == 0) return len_t;
57 if (len_t == 0) return len_s;
58 if (!strncmp(s, t, std::min(len_s, len_t))) return 0;
59
60 // create two work vectors of integer distances
61 size_t len = len_t + 1;
62 std::vector<size_t> v0(len);
63 std::vector<size_t> v1(len);
64
65 // initialize v0 (the previous row of distances)
66 // this row is A[0][i]: edit distance for an empty s
67 // the distance is just the number of characters to delete from t
68 for (size_t i = 0; i < len; i++)
69 v0[i] = i;
70
71 for (size_t i = 0; i < len_s; i++) {
72 // calculate v1 (current row distances) from the previous row v0
73
74 // first element of v1 is A[i+1][0]
75 // edit distance is delete (i+1) chars from s to match empty t
76 v1[0] = i + 1;
77
78 // use formula to fill in the rest of the row
79 for (size_t j = 0; j < len_t; j++) {
80 size_t cost = (s[i] == t[j]) ? 0 : 1;
81 v1[j+1] = std::min(v1[j] + 1,
82 std::min(v0[j + 1] + 1,
83 v0[j] + cost));
84 }
85
86 // copy v1 (current row) to v0 (previous row) for next iteration
87 for (size_t j = 0; j < len; j++)
88 v0[j] = v1[j];
89 }
90
91 return v1[len_t];
92 }
93
94}
Namespace for MueLu classes and methods.
size_t LevenshteinDistance(const char *s, size_t len_s, const char *t, size_t len_t)