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juce_FFT_test.cpp
/*
==============================================================================
This file is part of the JUCE library.
Copyright (c) 2022 - Raw Material Software Limited
JUCE is an open source library subject to commercial or open-source
licensing.
By using JUCE, you agree to the terms of both the JUCE 7 End-User License
Agreement and JUCE Privacy Policy.
End User License Agreement: www.juce.com/juce-7-licence
Privacy Policy: www.juce.com/juce-privacy-policy
Or: You may also use this code under the terms of the GPL v3 (see
www.gnu.org/licenses).
JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
DISCLAIMED.
==============================================================================
*/
namespace juce::dsp
{
struct FFTUnitTest final : public UnitTest
{
FFTUnitTest()
: UnitTest ("FFT", UnitTestCategories::dsp)
{}
static void fillRandom (Random& random, Complex<float>* buffer, size_t n)
{
for (size_t i = 0; i < n; ++i)
buffer[i] = Complex<float> ((2.0f * random.nextFloat()) - 1.0f,
(2.0f * random.nextFloat()) - 1.0f);
}
static void fillRandom (Random& random, float* buffer, size_t n)
{
for (size_t i = 0; i < n; ++i)
buffer[i] = (2.0f * random.nextFloat()) - 1.0f;
}
static Complex<float> freqConvolution (const Complex<float>* in, float freq, size_t n)
{
Complex<float> sum (0.0, 0.0);
for (size_t i = 0; i < n; ++i)
sum += in[i] * exp (Complex<float> (0, static_cast<float> (i) * freq));
return sum;
}
static void performReferenceFourier (const Complex<float>* in, Complex<float>* out,
size_t n, bool reverse)
{
auto base_freq = static_cast<float> (((reverse ? 1.0 : -1.0) * MathConstants<double>::twoPi)
/ static_cast<float> (n));
for (size_t i = 0; i < n; ++i)
out[i] = freqConvolution (in, static_cast<float> (i) * base_freq, n);
}
static void performReferenceFourier (const float* in, Complex<float>* out,
size_t n, bool reverse)
{
HeapBlock<Complex<float>> buffer (n);
for (size_t i = 0; i < n; ++i)
buffer.getData()[i] = Complex<float> (in[i], 0.0f);
float base_freq = static_cast<float> (((reverse ? 1.0 : -1.0) * MathConstants<double>::twoPi)
/ static_cast<float> (n));
for (size_t i = 0; i < n; ++i)
out[i] = freqConvolution (buffer.getData(), static_cast<float> (i) * base_freq, n);
}
//==============================================================================
template <typename Type>
static bool checkArrayIsSimilar (Type* a, Type* b, size_t n) noexcept
{
for (size_t i = 0; i < n; ++i)
if (std::abs (a[i] - b[i]) > 1e-3f)
return false;
return true;
}
struct RealTest
{
static void run (FFTUnitTest& u)
{
Random random (378272);
for (size_t order = 0; order <= 8; ++order)
{
auto n = (1u << order);
FFT fft ((int) order);
HeapBlock<float> input (n);
HeapBlock<Complex<float>> reference (n), output (n);
fillRandom (random, input.getData(), n);
performReferenceFourier (input.getData(), reference.getData(), n, false);
// fill only first half with real numbers
zeromem (output.getData(), n * sizeof (Complex<float>));
memcpy (reinterpret_cast<float*> (output.getData()), input.getData(), n * sizeof (float));
fft.performRealOnlyForwardTransform ((float*) output.getData());
u.expect (checkArrayIsSimilar (reference.getData(), output.getData(), n));
// fill only first half with real numbers
zeromem (output.getData(), n * sizeof (Complex<float>));
memcpy (reinterpret_cast<float*> (output.getData()), input.getData(), n * sizeof (float));
fft.performRealOnlyForwardTransform ((float*) output.getData(), true);
std::fill (reference.getData() + ((n >> 1) + 1), reference.getData() + n, std::complex<float> (0.0f));
u.expect (checkArrayIsSimilar (reference.getData(), output.getData(), (n >> 1) + 1));
memcpy (output.getData(), reference.getData(), n * sizeof (Complex<float>));
fft.performRealOnlyInverseTransform ((float*) output.getData());
u.expect (checkArrayIsSimilar ((float*) output.getData(), input.getData(), n));
}
}
};
struct FrequencyOnlyTest
{
static void run (FFTUnitTest& u)
{
Random random (378272);
for (size_t order = 0; order <= 8; ++order)
{
auto n = (1u << order);
FFT fft ((int) order);
std::vector<float> inout ((size_t) n << 1), reference ((size_t) n << 1);
std::vector<Complex<float>> frequency (n);
fillRandom (random, inout.data(), n);
zeromem (reference.data(), sizeof (float) * ((size_t) n << 1));
performReferenceFourier (inout.data(), frequency.data(), n, false);
for (size_t i = 0; i < n; ++i)
reference[i] = std::abs (frequency[i]);
for (auto ignoreNegative : { false, true })
{
auto inoutCopy = inout;
fft.performFrequencyOnlyForwardTransform (inoutCopy.data(), ignoreNegative);
auto numMatching = ignoreNegative ? (n / 2) + 1 : n;
u.expect (checkArrayIsSimilar (inoutCopy.data(), reference.data(), numMatching));
}
}
}
};
struct ComplexTest
{
static void run (FFTUnitTest& u)
{
Random random (378272);
for (size_t order = 0; order <= 7; ++order)
{
auto n = (1u << order);
FFT fft ((int) order);
HeapBlock<Complex<float>> input (n), buffer (n), output (n), reference (n);
fillRandom (random, input.getData(), n);
performReferenceFourier (input.getData(), reference.getData(), n, false);
memcpy (buffer.getData(), input.getData(), sizeof (Complex<float>) * n);
fft.perform (buffer.getData(), output.getData(), false);
u.expect (checkArrayIsSimilar (output.getData(), reference.getData(), n));
memcpy (buffer.getData(), reference.getData(), sizeof (Complex<float>) * n);
fft.perform (buffer.getData(), output.getData(), true);
u.expect (checkArrayIsSimilar (output.getData(), input.getData(), n));
}
}
};
template <class TheTest>
void runTestForAllTypes (const char* unitTestName)
{
beginTest (unitTestName);
TheTest::run (*this);
}
void runTest() override
{
runTestForAllTypes<RealTest> ("Real input numbers Test");
runTestForAllTypes<FrequencyOnlyTest> ("Frequency only Test");
runTestForAllTypes<ComplexTest> ("Complex input numbers Test");
}
};
static FFTUnitTest fftUnitTest;
} // namespace juce::dsp
juce::UnitTest::UnitTest
UnitTest(const String &name, const String &category=String())
Definition juce_UnitTest.cpp:26
juce::UnitTest::beginTest
void beginTest(const String &testName)
Definition juce_UnitTest.cpp:89
juce::UnitTest::runTest
virtual void runTest()=0
juce::MathConstants::twoPi
static constexpr FloatType twoPi
Definition juce_MathsFunctions.h:144