Add new port math/nfft

NFFT is a software library, written in C, for computing non-equispaced fast
Fourier transforms and related variations. It implements the following
transforms:

1. Non-equispaced fast Fourier transform (NFFT)
 - forward transform (NFFT), i.e. frequency to time/space domain
 - adjoint transform (adjoint NFFT), i.e. time/space to frequency domain

2. Generalisations
 - to arbitrary nodes in time and frequency domain (NNFFT)
 - to real-valued data, i.e. (co)sine transforms, (NFCT, NFST)
 - to the sphere S^2 (NFSFT)
 - to the rotation group (NFSOFT)
 - to the hyperbolic cross (NSFFT)
3. Generalised inverse transformations based on iterative methods, e.g.
   CGNR/CGNE

PR:		223429
Submitted by:	Michael Danilov <mike.d.ft402@gmail.com>

1 files changed, 56 insertions, 0 deletions

diff --git a/math/nfft/files/cpow.c b/math/nfft/files/cpow.c
new file mode 100644
index 000000000000..082238b3a210
--- /dev/null
+++ b/math/nfft/files/cpow.c
@@ -0,0 +1,56 @@
+/* $NetBSD: cpow.c,v 1.1 2007/08/20 16:01:35 drochner Exp $ */
+
+/*-
+ * Copyright (c) 2007 The NetBSD Foundation, Inc.
+ * All rights reserved.
+ *
+ * This code is derived from software written by Stephen L. Moshier.
+ * It is redistributed by the NetBSD Foundation by permission of the author.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <complex.h>
+#include <math.h>
+
+double complex
+cpow(double complex a, double complex z)
+{
+	double complex w;
+	double x, y, r, theta, absa, arga;
+
+	x = creal(z);
+	y = cimag(z);
+	absa = cabs(a);
+	if (absa == 0.0) {
+		return (0.0 + 0.0 * I);
+	}
+	arga = carg(a);
+	r = pow(absa, x);
+	theta = x * arga;
+	if (y != 0.0) {
+		r = r * exp(-y * arga);
+		theta = theta + y * log(absa);
+	}
+	w = r * cos(theta) + (r * sin(theta)) * I;
+	return w;
+}