comparison fft/nayukic/fft.h @ 32:ebc87a62321d

Add Nayuki fft.c compiled to JS

+/* 
+ * Free FFT and convolution (C)
+ * 
+ * Copyright (c) 2014 Project Nayuki
+ * http://www.nayuki.io/page/free-small-fft-in-multiple-languages
+ * 
+ * (MIT License)
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+ * the Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ * - The above copyright notice and this permission notice shall be included in
+ *   all copies or substantial portions of the Software.
+ * - The Software is provided "as is", without warranty of any kind, express or
+ *   implied, including but not limited to the warranties of merchantability,
+ *   fitness for a particular purpose and noninfringement. In no event shall the
+ *   authors or copyright holders be liable for any claim, damages or other
+ *   liability, whether in an action of contract, tort or otherwise, arising from,
+ *   out of or in connection with the Software or the use or other dealings in the
+ *   Software.
+ */
+
+
+/* 
+ * Computes the discrete Fourier transform (DFT) of the given complex vector, storing the result back into the vector.
+ * The vector can have any length. This is a wrapper function. Returns 1 (true) if successful, 0 (false) otherwise (out of memory).
+ */
+int transform(double real[], double imag[], size_t n);
+
+/* 
+ * Computes the inverse discrete Fourier transform (IDFT) of the given complex vector, storing the result back into the vector.
+ * The vector can have any length. This is a wrapper function. This transform does not perform scaling, so the inverse is not a true inverse.
+ * Returns 1 (true) if successful, 0 (false) otherwise (out of memory).
+ */
+int inverse_transform(double real[], double imag[], size_t n);
+
+/* 
+ * Computes the discrete Fourier transform (DFT) of the given complex vector, storing the result back into the vector.
+ * The vector's length must be a power of 2. Uses the Cooley-Tukey decimation-in-time radix-2 algorithm.
+ * Returns 1 (true) if successful, 0 (false) otherwise (n is not a power of 2, or out of memory).
+ */
+int transform_radix2(double real[], double imag[], size_t n);
+
+typedef struct {
+    double *cos;
+    double *sin;
+    int levels;
+} tables;
+
+tables *precalc(size_t n);
+void dispose(tables *);
+void transform_radix2_precalc(double real[], double imag[], int n, tables *tables);
+
+/* 
+ * Computes the discrete Fourier transform (DFT) of the given complex vector, storing the result back into the vector.
+ * The vector can have any length. This requires the convolution function, which in turn requires the radix-2 FFT function.
+ * Uses Bluestein's chirp z-transform algorithm. Returns 1 (true) if successful, 0 (false) otherwise (out of memory).
+ */
+int transform_bluestein(double real[], double imag[], size_t n);
+
+/* 
+ * Computes the circular convolution of the given real vectors. Each vector's length must be the same.
+ * Returns 1 (true) if successful, 0 (false) otherwise (out of memory).
+ */
+int convolve_real(const double x[], const double y[], double out[], size_t n);
+
+/* 
+ * Computes the circular convolution of the given complex vectors. Each vector's length must be the same.
+ * Returns 1 (true) if successful, 0 (false) otherwise (out of memory).
+ */
+int convolve_complex(const double xreal[], const double ximag[], const double yreal[], const double yimag[], double outreal[], double outimag[], size_t n);
+