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/* Copyright 2023 Yann ORLAREY
*
* Licensed 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.
*/
#include <algorithm>
#include <functional>
#include <random>
#include "bitwiseOperations.hh"
#include "check.hh"
#include "interval_algebra.hh"
#include "interval_def.hh"
namespace itv {
//------------------------------------------------------------------------------------------
// Interval Xor
// interval Xor(const interval& x, const interval& y);
// void testXor();
static double myXor(double x, double y)
{
auto a = saturatedIntCast(x);
auto b = saturatedIntCast(y);
int c = a ^ b;
return double(c);
}
// BRUTE FORCE
interval interval_algebra::Xor(const interval& x, const interval& y)
{
if (x.isEmpty() || y.isEmpty()) {
return empty();
}
auto x0 = saturatedIntCast(x.lo());
auto x1 = saturatedIntCast(x.hi());
auto y0 = saturatedIntCast(y.lo());
auto y1 = saturatedIntCast(y.hi());
SInterval z = bitwiseSignedXOr({x0, x1}, {y0, y1});
int precision = std::min(
x.lsb(), y.lsb()); // output precision cannot be finer than that of the input intervals
// if both intervals are singletons, the lsb is the least significant bit of the only element of
// the interval
if ((x0 == x1) && (y0 == y1)) {
int v = x0 ^ y0;
precision = 0;
while (((v & 1) == 0) && (v != 0)) { // while we encounter zeroes at the lower end of v
v = v / 2;
precision++;
}
}
// if only one of the intervals is a singleton, all of the variation is due to the other
// interval, which transmits its lsb
if (x0 == x1) {
precision = y.lsb();
}
if (y1 == y0) {
precision = x.lsb();
}
return {double(z.lo), double(z.hi), precision};
}
void interval_algebra::testXor()
{
std::random_device R;
std::default_random_engine generator(R());
std::uniform_int_distribution lx(0, 10);
std::uniform_int_distribution ly(0, 10);
analyzeBinaryMethod(10, 20000, "Xor", interval(-1000, -800, lx(generator)),
interval(127, 127, ly(generator)), myXor, &interval_algebra::Xor);
analyzeBinaryMethod(10, 20000, "Xor", interval(-1000, -800, lx(generator)),
interval(127, 127, ly(generator)), myXor, &interval_algebra::Xor);
analyzeBinaryMethod(10, 20000, "Xor", interval(-1000, -800, lx(generator)),
interval(123, 123, ly(generator)), myXor, &interval_algebra::Xor);
analyzeBinaryMethod(10, 20000, "Xor", interval(-1000, -800, lx(generator)),
interval(123, 123, ly(generator)), myXor, &interval_algebra::Xor);
analyzeBinaryMethod(10, 20000, "Xor", interval(-128, 128, lx(generator)),
interval(127, 127, ly(generator)), myXor, &interval_algebra::Xor);
analyzeBinaryMethod(10, 20000, "Xor", interval(-128, 128, lx(generator)),
interval(127, 127, ly(generator)), myXor, &interval_algebra::Xor);
analyzeBinaryMethod(10, 20000, "Xor", interval(0, 1000, lx(generator)),
interval(63, 127, ly(generator)), myXor, &interval_algebra::Xor);
analyzeBinaryMethod(10, 20000, "Xor", interval(0, 1000, lx(generator)),
interval(63, 127, ly(generator)), myXor, &interval_algebra::Xor);
analyzeBinaryMethod(10, 20000, "Xor", interval(-1000, 1000, lx(generator)),
interval(63, 127, ly(generator)), myXor, &interval_algebra::Xor);
analyzeBinaryMethod(10, 20000, "Xor", interval(-1000, 1000, lx(generator)),
interval(63, 127, ly(generator)), myXor, &interval_algebra::Xor);
analyzeBinaryMethod(10, 2000, "Xor", interval(10, 20), interval(0), myXor,
&interval_algebra::Xor);
analyzeBinaryMethod(10, 2000, "Xor", interval(0), interval(15, 25), myXor,
&interval_algebra::Xor);
analyzeBinaryMethod(10, 2000, "Xor", interval(0), interval(0), myXor, &interval_algebra::Xor);
}
} // namespace itv
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