1 // ******************************************************************************
2 //
3 // Title: Force Field X.
4 // Description: Force Field X - Software for Molecular Biophysics.
5 // Copyright: Copyright (c) Michael J. Schnieders 2001-2025.
6 //
7 // This file is part of Force Field X.
8 //
9 // Force Field X is free software; you can redistribute it and/or modify it
10 // under the terms of the GNU General Public License version 3 as published by
11 // the Free Software Foundation.
12 //
13 // Force Field X is distributed in the hope that it will be useful, but WITHOUT
14 // ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
15 // FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
16 // details.
17 //
18 // You should have received a copy of the GNU General Public License along with
19 // Force Field X; if not, write to the Free Software Foundation, Inc., 59 Temple
20 // Place, Suite 330, Boston, MA 02111-1307 USA
21 //
22 // Linking this library statically or dynamically with other modules is making a
23 // combined work based on this library. Thus, the terms and conditions of the
24 // GNU General Public License cover the whole combination.
25 //
26 // As a special exception, the copyright holders of this library give you
27 // permission to link this library with independent modules to produce an
28 // executable, regardless of the license terms of these independent modules, and
29 // to copy and distribute the resulting executable under terms of your choice,
30 // provided that you also meet, for each linked independent module, the terms
31 // and conditions of the license of that module. An independent module is a
32 // module which is not derived from or based on this library. If you modify this
33 // library, you may extend this exception to your version of the library, but
34 // you are not obligated to do so. If you do not wish to do so, delete this
35 // exception statement from your version.
36 //
37 // ******************************************************************************
38 package ffx.numerics.fft;
39
40 /**
41 * The Complex FFT supports interleaved or blocked data.
42 * <p>
43 * For interleaved data, the complex data is stored in the following way:
44 * <PRE>
45 * Re(d[i]) = data[offset + stride*i]
46 * Im(d[i]) = data[offset + stride*i + 1]
47 * </PRE>
48 * <p>
49 * For blocked data, the complex data is stored in the following way:
50 * <PRE>
51 * Re(d[i]) = data[offset + stride*i]
52 * Im(d[i]) = data[offset + stride*i + im]
53 * where the offset to the imaginary part is specified by the im parameter.
54 * For BLOCKED_X, im = nX.
55 * For BLOCKED_XY, im >= nX*nY.
56 * </PRE>
57 */
58 public enum DataLayout2D {
59 /**
60 * Interleaved data layout.
61 */
62 INTERLEAVED,
63 /**
64 * Blocked data layout with im = nX.
65 */
66 BLOCKED_X,
67 /**
68 * Blocked data layout with im >= nX*nY.
69 */
70 BLOCKED_XY
71 }