initial commit

Tests/PFFFTTests/PFFFTTests.swift

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+import Testing
+import ComplexModule
+@testable import PFFFT
+
+@Test func fftFloat() async throws {
+
+    let fft = try FFT<Complex<Float>>(n: 16)
+    let signal = fft.makeSignalBuffer()
+    let spectrum = fft.makeSpectrumBuffer()
+
+    signal.mutateEach { (i, v) in
+        v = Complex(Float(i) + 1.0, Float(i) - 2.0)
+    }
+
+    fft.forward(signal: signal, spectrum: spectrum)
+
+    let result = spectrum.map { $0 }
+    let expected: [Complex<Float>] = [
+      .init(136.0, 88.0),
+      .init(-48.218716, 32.218716),
+      .init(-27.31371, 11.313708),
+      .init(-19.972847, 3.972846),
+      .init(-16.0, 0.0),
+      .init(-13.345428, -2.6545706),
+      .init(-11.313709, -4.6862917),
+      .init(-9.591298, -6.408703),
+      .init(-8.0, -8.0),
+      .init(-6.408703, -9.591298),
+      .init(-4.6862917, -11.313708),
+      .init(-2.6545706, -13.345429),
+      .init(0.0, -16.0),
+      .init(3.972845, -19.972847),
+      .init(11.313707, -27.31371),
+      .init(32.218716, -48.218716),
+    ]
+    zip(result, expected).forEach { r, e in
+        #expect(r.isApproximatelyEqual(to: e))
+    }
+
+    fft.inverse(spectrum: spectrum, signal: signal)
+
+    let signalResult = signal.map { $0 }
+    let signalExpected = (0..<16).map { i in
+        Complex(Float(i) + 1.0, Float(i) - 2.0) * 16
+    }
+
+    zip(signalResult, signalExpected).forEach { r, e in
+        #expect(r.isApproximatelyEqual(to: e))
+    }
+}