1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206 | #pragma once
#include <functional><--- Include file: not found. Please note: Cppcheck does not need standard library headers to get proper results.
#include <type_traits><--- Include file: not found. Please note: Cppcheck does not need standard library headers to get proper results.
#include "snippet/aliases.hpp"
#include "snippet/iterations.hpp"
#include "internal/dev_env.hpp"
#include "internal/types.hpp"
#include "adaptor/gnu/hash_table.hpp"
#include "numeric/limits.hpp"
namespace uni {
template<class Signature>
struct extremum_seeker;
template<class T, std::floating_point Arg>
struct extremum_seeker<T(Arg)> {
using value_type = T;
using arg_type = Arg;
private:
std::function<T(Arg)> _f;
template<const internal::size_t ITERATIONS>
std::pair<arg_type, arg_type> search(arg_type low, arg_type high, const auto comp) const noexcept(NO_EXCEPT) {
REP(ITERATIONS) {
const auto p = low + (high - low) / 3;
const auto q = high - (high - low) / 3;
if(comp(p, q)) high = q;
else low = p;
}
return { low, high };
}
public:
template<class F>
requires std::same_as<std::invoke_result_t<F, Arg>, T>
extremum_seeker(F&& f) noexcept(NO_EXCEPT) : _f(std::forward<F>(f)) {};<--- Struct 'extremum_seeker' has a constructor with 1 argument that is not explicit. [+]Struct 'extremum_seeker' has a constructor with 1 argument that is not explicit. Such, so called "Converting constructors", should in general be explicit for type safety reasons as that prevents unintended implicit conversions.
template<const internal::size_t ITERATIONS = 100'000>
std::pair<arg_type, arg_type> arg_min(
arg_type low = uni::numeric_limits<arg_type>::arithmetic_negative_infinity(),
arg_type high = uni::numeric_limits<arg_type>::arithmetic_infinity()
) const noexcept(NO_EXCEPT) {
const auto comp = [&](const arg_type lhs, const arg_type rhs) noexcept(NO_EXCEPT) {
return this->_f(lhs) < this->_f(rhs);
};
return this->search<ITERATIONS>(low, high, comp);
}
template<const internal::size_t ITERATIONS = 100'000>
std::pair<arg_type, arg_type> arg_max(
arg_type low = uni::numeric_limits<arg_type>::arithmetic_negative_infinity(),
arg_type high = uni::numeric_limits<arg_type>::arithmetic_infinity()
) const noexcept(NO_EXCEPT) {
const auto comp = [&](const arg_type lhs, const arg_type rhs) noexcept(NO_EXCEPT) {
return this->_f(lhs) > this->_f(rhs);
};
return this->search<ITERATIONS>(low, high, comp);
}
template<const internal::size_t ITERATIONS = 100'000>
auto min(
const arg_type _low = uni::numeric_limits<arg_type>::arithmetic_negative_infinity(),
const arg_type _high = uni::numeric_limits<arg_type>::arithmetic_infinity()
) const noexcept(NO_EXCEPT) {
const auto [ low, high ] = this->arg_min<ITERATIONS>(_low, _high);
auto res = std::min(this->_f(low), this->_f(high));
FOR(x, low, high) chmin(res, this->_f(x));
return res;
}
template<const internal::size_t ITERATIONS = 100'000>
auto max(
const arg_type _low = uni::numeric_limits<arg_type>::arithmetic_negative_infinity(),
const arg_type _high = uni::numeric_limits<arg_type>::arithmetic_infinity()
) const noexcept(NO_EXCEPT) {
const auto [ low, high ] = this->arg_max<ITERATIONS>(_low, _high);
auto res = std::max(this->_f(low), this->_f(high));
FOR(x, low, high) chmax(res, this->_f(x));
return res;
}
};
template<class T, std::integral Arg>
struct extremum_seeker<T(Arg)> {
using value_type = T;
using arg_type = Arg;
private:
std::function<T(Arg)> _f;
std::vector<arg_type> _fib = { 0, 1 };
gnu::gp_hash_table<arg_type, value_type> _cache;
auto _expand(const arg_type size) noexcept(NO_EXCEPT) {
assert(size >= 0);
this->_fib.reserve(std::bit_width(to_unsigned(size)));
if(this->_fib.back() < size) {
do {
this->_fib.emplace_back(
this->_fib[std::ranges::size(this->_fib) - 1] +
this->_fib[std::ranges::size(this->_fib) - 2]
);
} while(this->_fib.back() < size);
return std::ranges::prev(this->_fib.end());
}
return std::ranges::lower_bound(this->_fib, size);
}
auto _func(const arg_type size) noexcept(NO_EXCEPT) {
if(this->_cache.contains(size)) return this->_cache[size];
return this->_cache[size] = this->_f(size);
}
auto _search(arg_type low, const arg_type high, const auto comp) noexcept(NO_EXCEPT) {
if(low == high) return low;
auto _low = low - 1;
const auto itr = this->_expand(high - _low + 1);
auto _high = *itr + _low;
auto diff = *std::ranges::prev(itr);
while(true) {
const auto p = _high - diff;
const auto q = _low + diff;
if(p == q) return p;
if(comp(p, q)) _high = q;
else _low = p;
diff = diff - (q - p);
}
}
public:
template<class F>
requires std::same_as<std::invoke_result_t<F, Arg>, T>
extremum_seeker(F&& f, const arg_type init_size = 0) noexcept(NO_EXCEPT)<--- Struct 'extremum_seeker' has a constructor with 1 argument that is not explicit. [+]Struct 'extremum_seeker' has a constructor with 1 argument that is not explicit. Such, so called "Converting constructors", should in general be explicit for type safety reasons as that prevents unintended implicit conversions.
: _f(std::forward<F>(f))
{
this->_expand(init_size);
}
auto arg_min(
const arg_type low = uni::numeric_limits<arg_type>::arithmetic_negative_infinity(),
const arg_type high = uni::numeric_limits<arg_type>::arithmetic_infinity()
) noexcept(NO_EXCEPT) {
const auto comp = [&](const arg_type lhs, const arg_type rhs) noexcept(NO_EXCEPT) {
if(high < rhs) return true;
return this->_func(lhs) < this->_func(rhs);
};
return this->_search(low, high, comp);
}
auto arg_max(
const arg_type low = uni::numeric_limits<arg_type>::arithmetic_negative_infinity(),
const arg_type high = uni::numeric_limits<arg_type>::arithmetic_infinity()
) noexcept(NO_EXCEPT) {
const auto comp = [&](const arg_type lhs, const arg_type rhs) noexcept(NO_EXCEPT) {
if(high < rhs) return true;
return this->_func(lhs) > this->_func(rhs);
};
return this->_search(low, high, comp);
}
inline auto min(
const arg_type _low = uni::numeric_limits<arg_type>::arithmetic_negative_infinity(),
const arg_type high = uni::numeric_limits<arg_type>::arithmetic_infinity()
) noexcept(NO_EXCEPT) {
return this->_func(this->arg_min(_low, high));
}
inline auto max(
const arg_type _low = uni::numeric_limits<arg_type>::arithmetic_negative_infinity(),
const arg_type high = uni::numeric_limits<arg_type>::arithmetic_infinity()
) noexcept(NO_EXCEPT) {
return this->_func(this->arg_max(_low, high));
}
};
} // namespace uni
|