64 lines · cpp
1//===-- unittests/Runtime/Random.cpp ----------------------------*- C++ -*-===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8 9#include "flang/Runtime/random.h"10#include "gtest/gtest.h"11#include "flang-rt/runtime/descriptor.h"12#include "flang-rt/runtime/type-code.h"13#include <cmath>14 15using namespace Fortran::runtime;16 17TEST(RandomNumber, Real4) {18 StaticDescriptor<1> statDesc;19 Descriptor &harvest{statDesc.descriptor()};20 static constexpr int n{10000};21 float xs[n]{};22 SubscriptValue extent[1]{n};23 harvest.Establish(TypeCategory::Real, 4, xs, 1, extent);24 RTNAME(RandomNumber)(harvest, __FILE__, __LINE__);25 double sum{0};26 for (int j{0}; j < n; ++j) {27 sum += xs[j];28 }29 double mean{sum / n};30 std::fprintf(stderr, "mean of %d random numbers: %g\n", n, mean);31 EXPECT_GE(mean, 0.95 * 0.5); // mean of uniform dist [0..1] is of course 0.532 EXPECT_LE(mean, 1.05 * 0.5);33 double sumsq{0};34 for (int j{0}; j < n; ++j) {35 double diff{xs[j] - mean};36 sumsq += diff * diff;37 }38 double sdev{std::sqrt(sumsq / n)};39 std::fprintf(stderr, "stddev of %d random numbers: %g\n", n, sdev);40 double expect{1.0 / std::sqrt(12.0)}; // stddev of uniform dist [0..1]41 EXPECT_GE(sdev, 0.95 * expect);42 EXPECT_LT(sdev, 1.05 * expect);43}44 45TEST(RandomNumber, RandomSeed) {46 StaticDescriptor<1> statDesc[2];47 Descriptor &desc{statDesc[0].descriptor()};48 std::int32_t n;49 desc.Establish(TypeCategory::Integer, 4, &n, 0, nullptr);50 RTNAME(RandomSeedSize)(&desc, __FILE__, __LINE__);51 EXPECT_EQ(n, 1);52 SubscriptValue extent[1]{1};53 desc.Establish(TypeCategory::Integer, 4, &n, 1, extent);54 RTNAME(RandomSeedGet)(&desc, __FILE__, __LINE__);55 Descriptor &harvest{statDesc[1].descriptor()};56 float x;57 harvest.Establish(TypeCategory::Real, 4, &x, 1, extent);58 RTNAME(RandomNumber)(harvest, __FILE__, __LINE__);59 float got{x};60 RTNAME(RandomSeedPut)(&desc, __FILE__, __LINE__); // n from RandomSeedGet()61 RTNAME(RandomNumber)(harvest, __FILE__, __LINE__);62 EXPECT_EQ(x, got);63}64