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juce_FFT_test.cpp
1/*
2 ==============================================================================
3
4 This file is part of the JUCE library.
5 Copyright (c) 2017 - ROLI Ltd.
6
7 JUCE is an open source library subject to commercial or open-source
8 licensing.
9
10 By using JUCE, you agree to the terms of both the JUCE 5 End-User License
11 Agreement and JUCE 5 Privacy Policy (both updated and effective as of the
12 27th April 2017).
13
14 End User License Agreement: www.juce.com/juce-5-licence
15 Privacy Policy: www.juce.com/juce-5-privacy-policy
16
17 Or: You may also use this code under the terms of the GPL v3 (see
18 www.gnu.org/licenses).
19
20 JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
21 EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
22 DISCLAIMED.
23
24 ==============================================================================
25*/
26
27 namespace juce
28{
29 namespace dsp
30{
31
32 struct FFTUnitTest : public UnitTest
33{
34 FFTUnitTest()
35 : UnitTest ("FFT", UnitTestCategories::dsp)
36 {}
37
38 static void fillRandom (Random& random, Complex<float>* buffer, size_t n)
39 {
40 for (size_t i = 0; i < n; ++i)
41 buffer[i] = Complex<float> ((2.0f * random.nextFloat()) - 1.0f,
42 (2.0f * random.nextFloat()) - 1.0f);
43 }
44
45 static void fillRandom (Random& random, float* buffer, size_t n)
46 {
47 for (size_t i = 0; i < n; ++i)
48 buffer[i] = (2.0f * random.nextFloat()) - 1.0f;
49 }
50
51 static Complex<float> freqConvolution (const Complex<float>* in, float freq, size_t n)
52 {
53 Complex<float> sum (0.0, 0.0);
54 for (size_t i = 0; i < n; ++i)
55 sum += in[i] * exp (Complex<float> (0, static_cast<float> (i) * freq));
56
57 return sum;
58 }
59
60 static void performReferenceFourier (const Complex<float>* in, Complex<float>* out,
61 size_t n, bool reverse)
62 {
63 auto base_freq = static_cast<float> (((reverse ? 1.0 : -1.0) * MathConstants<double>::twoPi)
64 / static_cast<float> (n));
65
66 for (size_t i = 0; i < n; ++i)
67 out[i] = freqConvolution (in, static_cast<float>(i) * base_freq, n);
68 }
69
70 static void performReferenceFourier (const float* in, Complex<float>* out,
71 size_t n, bool reverse)
72 {
73 HeapBlock<Complex<float>> buffer (n);
74
75 for (size_t i = 0; i < n; ++i)
76 buffer.getData()[i] = Complex<float> (in[i], 0.0f);
77
78 float base_freq = static_cast<float> (((reverse ? 1.0 : -1.0) * MathConstants<double>::twoPi)
79 / static_cast<float> (n));
80
81 for (size_t i = 0; i < n; ++i)
82 out[i] = freqConvolution (buffer.getData(), static_cast<float>(i) * base_freq, n);
83 }
84
85
86 //==============================================================================
87 template <typename Type>
88 static bool checkArrayIsSimilar (Type* a, Type* b, size_t n) noexcept
89 {
90 for (size_t i = 0; i < n; ++i)
91 if (std::abs (a[i] - b[i]) > 1e-3f)
92 return false;
93
94 return true;
95 }
96
97 struct RealTest
98 {
99 static void run (FFTUnitTest& u)
100 {
101 Random random (378272);
102
103 for (size_t order = 0; order <= 8; ++order)
104 {
105 auto n = (1u << order);
106
107 FFT fft ((int) order);
108
109 HeapBlock<float> input (n);
110 HeapBlock<Complex<float>> reference (n), output (n);
111
112 fillRandom (random, input.getData(), n);
113 performReferenceFourier (input.getData(), reference.getData(), n, false);
114
115 // fill only first half with real numbers
116 zeromem (output.getData(), n * sizeof (Complex<float>));
117 memcpy (reinterpret_cast<float*> (output.getData()), input.getData(), n * sizeof (float));
118
119 fft.performRealOnlyForwardTransform ((float*) output.getData());
120 u.expect (checkArrayIsSimilar (reference.getData(), output.getData(), n));
121
122 // fill only first half with real numbers
123 zeromem (output.getData(), n * sizeof (Complex<float>));
124 memcpy (reinterpret_cast<float*> (output.getData()), input.getData(), n * sizeof (float));
125
126 fft.performRealOnlyForwardTransform ((float*) output.getData(), true);
127 std::fill (reference.getData() + ((n >> 1) + 1), reference.getData() + n, std::complex<float> (0.0f));
128 u.expect (checkArrayIsSimilar (reference.getData(), output.getData(), (n >> 1) + 1));
129
130 memcpy (output.getData(), reference.getData(), n * sizeof (Complex<float>));
131 fft.performRealOnlyInverseTransform ((float*) output.getData());
132 u.expect (checkArrayIsSimilar ((float*) output.getData(), input.getData(), n));
133 }
134 }
135 };
136
137 struct FrequencyOnlyTest
138 {
139 static void run(FFTUnitTest& u)
140 {
141 Random random (378272);
142 for (size_t order = 0; order <= 8; ++order)
143 {
144 auto n = (1u << order);
145
146 FFT fft ((int) order);
147
148 HeapBlock<float> inout (n << 1), reference (n << 1);
149 HeapBlock<Complex<float>> frequency (n);
150
151 fillRandom (random, inout.getData(), n);
152 zeromem (reference.getData(), sizeof (float) * (n << 1));
153 performReferenceFourier (inout.getData(), frequency.getData(), n, false);
154
155 for (size_t i = 0; i < n; ++i)
156 reference.getData()[i] = std::abs (frequency.getData()[i]);
157
158 fft.performFrequencyOnlyForwardTransform (inout.getData());
159
160 u.expect (checkArrayIsSimilar (inout.getData(), reference.getData(), n));
161 }
162 }
163 };
164
165 struct ComplexTest
166 {
167 static void run(FFTUnitTest& u)
168 {
169 Random random (378272);
170
171 for (size_t order = 0; order <= 7; ++order)
172 {
173 auto n = (1u << order);
174
175 FFT fft ((int) order);
176
177 HeapBlock<Complex<float>> input (n), buffer (n), output (n), reference (n);
178
179 fillRandom (random, input.getData(), n);
180 performReferenceFourier (input.getData(), reference.getData(), n, false);
181
182 memcpy (buffer.getData(), input.getData(), sizeof (Complex<float>) * n);
183 fft.perform (buffer.getData(), output.getData(), false);
184
185 u.expect (checkArrayIsSimilar (output.getData(), reference.getData(), n));
186
187 memcpy (buffer.getData(), reference.getData(), sizeof (Complex<float>) * n);
188 fft.perform (buffer.getData(), output.getData(), true);
189
190
191 u.expect (checkArrayIsSimilar (output.getData(), input.getData(), n));
192 }
193 }
194 };
195
196 template <class TheTest>
197 void runTestForAllTypes (const char* unitTestName)
198 {
199 beginTest (unitTestName);
200
201 TheTest::run (*this);
202 }
203
204 void runTest() override
205 {
206 runTestForAllTypes<RealTest> ("Real input numbers Test");
207 runTestForAllTypes<FrequencyOnlyTest> ("Frequency only Test");
208 runTestForAllTypes<ComplexTest> ("Complex input numbers Test");
209 }
210};
211
212 static FFTUnitTest fftUnitTest;
213
214} // namespace dsp
215} // namespace juce
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::MathConstants::twoPi
static const FloatType twoPi
Definition: juce_MathsFunctions.h:368