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/**
* Copyright (C) 2018-present MongoDB, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the Server Side Public License, version 1,
* as published by MongoDB, Inc.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* Server Side Public License for more details.
*
* You should have received a copy of the Server Side Public License
* along with this program. If not, see
* <http://www.mongodb.com/licensing/server-side-public-license>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the Server Side Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#include "mongo/platform/basic.h"
#include <cmath>
#include <limits>
#include <vector>
#include "mongo/unittest/unittest.h"
#include "mongo/util/summation.h"
namespace mongo {
namespace {
using limits = std::numeric_limits<long long>;
std::vector<long long> longValues = {
limits::min(),
limits::min() + 1,
limits::min() / 2,
-(1LL << 53),
-(1LL << 52),
-(1LL << 32),
-0x100,
-0xff,
-0xaa,
-0x55,
-1,
0,
1,
2,
0x55,
0x80,
0xaa,
0x100,
512,
1024,
2048,
1LL << 31,
1LL << 32,
1LL << 52,
1LL << 53,
limits::max() / 2,
#pragma warning(push)
// C4308: negative integral constant converted to unsigned type
#pragma warning(disable : 4308)
static_cast<long long>(1ULL << 63) - (1ULL << (63 - 53 - 1)), // Halfway between two doubles
#pragma warning(pop)
limits::max() - 1,
limits::max()};
std::vector<double> doubleValues = {
1.4831356930199802e-05, -3.121724665346865, 3041897608700.073, 1001318343149.7166,
-1714.6229586696593, 1731390114894580.8, 6.256645803154374e-08, -107144114533844.25,
-0.08839485091750919, -265119153.02185738, -0.02450615965231944, 0.0002684331017079073,
32079040427.68358, -0.04733295911845742, 0.061381859083076085, -25329.59126796951,
-0.0009567520620034965, -1553879364344.9932, -2.1101077525869814e-08, -298421079729.5547,
0.03182394834273594, 22.201944843278916, -33.35667991109125, 11496013.960449915,
-40652595.33210472, 3.8496066090328163, 2.5074042398147304e-08, -0.02208724071782122,
-134211.37290639878, 0.17640433666616578, 4.463787499171126, 9.959669945399718,
129265976.35224283, 1.5865526187526546e-07, -4746011.710555799, -712048598925.0789,
582214206210.4034, 0.025236204812875362, 530078170.91147506, -14.865307666195053,
1.6727994895185032e-05, -113386276.03121366, -6.135827207137054, 10644945799901.145,
-100848907797.1582, 2.2404406961625282e-08, 1.315662618424494e-09, -0.832190208349044,
-9.779323414999364, -546522170658.2997};
const double doubleValuesSum = 1636336982012512.5; // simple summation will yield wrong result
std::vector<double> specialValues = {-std::numeric_limits<double>::infinity(),
std::numeric_limits<double>::infinity(),
std::numeric_limits<double>::quiet_NaN()};
} // namespace
TEST(Summation, AddLongs) {
int iter = 0;
for (auto x : longValues) {
for (auto y : longValues) {
for (auto z : longValues) {
iter++;
DoubleDoubleSummation sum;
// This checks for correct results mod 2**64, which helps with checking correctness
// around the 2**53 transition between both doubles of the DoubleDouble result in
// int64 additions, as well off-by-one errors.
uint64_t checkUint64 =
static_cast<uint64_t>(x) + static_cast<uint64_t>(y) + static_cast<uint64_t>(z);
sum.addLong(x);
sum.addLong(y);
sum.addLong(z);
ASSERT(sum.isInteger());
if (!sum.fitsLong()) {
ASSERT(std::abs(sum.getDouble()) >= limits::max());
// Reduce sum to fit in a 64-bit integer.
while (!sum.fitsLong()) {
sum.addDouble(sum.getDouble() < 0 ? std::ldexp(1, 64) : -std::ldexp(1, 64));
}
}
ASSERT_EQUALS(static_cast<uint64_t>(sum.getLong()), checkUint64);
}
}
}
}
TEST(Summation, AddSpecial) {
for (auto x : specialValues) {
DoubleDoubleSummation sum;
// Check that a special number will result in that special number.
sum.addLong(-42);
sum.addLong(100);
sum.addDouble(x);
ASSERT(!sum.fitsLong());
ASSERT(!sum.isInteger());
if (std::isnan(x)) {
ASSERT(std::isnan(sum.getDouble()));
} else {
ASSERT_EQUALS(sum.getDouble(), x);
}
// Check that adding more numbers doesn't reset the special value.
sum.addDouble(-1E22);
sum.addLong(limits::min());
ASSERT(!sum.fitsLong());
if (std::isnan(x)) {
ASSERT(std::isnan(sum.getDouble()));
} else {
ASSERT_EQUALS(sum.getDouble(), x);
}
}
}
TEST(Summation, AddInvalid) {
DoubleDoubleSummation sum;
sum.addDouble(std::numeric_limits<double>::infinity());
sum.addDouble(-std::numeric_limits<double>::infinity());
ASSERT(std::isnan(sum.getDouble()));
ASSERT(!sum.fitsLong());
ASSERT(!sum.isInteger());
}
TEST(Summation, LongOverflow) {
DoubleDoubleSummation positive;
// Overflow should result in number no longer fitting in a long.
positive.addLong(limits::max());
positive.addLong(limits::max());
ASSERT(!positive.fitsLong());
// However, actual stored overflow should not overflow or lose precision.
positive.addLong(-limits::max());
ASSERT_EQUALS(positive.getLong(), limits::max());
DoubleDoubleSummation negative;
// Similarly for negative numbers.
negative.addLong(limits::min());
negative.addLong(-1);
ASSERT(!negative.fitsLong());
negative.addDouble(-1.0 * limits::min());
ASSERT_EQUALS(negative.getLong(), -1);
}
TEST(Summation, AddDoubles) {
DoubleDoubleSummation sum;
double straightSum = 0.0;
for (auto x : doubleValues) {
sum.addDouble(x);
straightSum += x;
}
ASSERT_EQUALS(sum.getDouble(), doubleValuesSum);
ASSERT(straightSum != sum.getDouble());
}
} // namespace mongo
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