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 import ffx.numerics.tornado.FFXTornado;
41 import uk.ac.manchester.tornado.api.ImmutableTaskGraph;
42 import uk.ac.manchester.tornado.api.TaskGraph;
43 import uk.ac.manchester.tornado.api.TornadoExecutionPlan;
44 import uk.ac.manchester.tornado.api.annotations.Parallel;
45 import uk.ac.manchester.tornado.api.common.TornadoDevice;
46 import uk.ac.manchester.tornado.api.runtime.TornadoRuntimeProvider;
47
48 import static uk.ac.manchester.tornado.api.enums.DataTransferMode.EVERY_EXECUTION;
49 import static uk.ac.manchester.tornado.api.math.TornadoMath.cos;
50 import static uk.ac.manchester.tornado.api.math.TornadoMath.floatPI;
51 import static uk.ac.manchester.tornado.api.math.TornadoMath.sin;
52
53 /**
54 * Proof-of-concept use of the TornadoVM for parallelization of Java code.
55 */
56 public class TornadoDFT {
57
58 float[] inReal;
59 float[] inImag;
60 float[] outReal;
61 float[] outImag;
62 long time;
63
64 /**
65 * Constructor.
66 *
67 * @param size The size of the DFT.
68 */
69 public TornadoDFT(int size) {
70 inReal = new float[size];
71 inImag = new float[size];
72 outReal = new float[size];
73 outImag = new float[size];
74 for (int i = 0; i < size; i++) {
75 inReal[i] = 1 / (float) (i + 2);
76 inImag[i] = 1 / (float) (i + 2);
77 }
78 }
79
80 /**
81 * Compute the Discrete Fourier Transform.
82 *
83 * @param inreal Input real values.
84 * @param inimag Input imaginary values.
85 * @param outreal Output real values.
86 * @param outimag Output imaginary values.
87 */
88 public static void computeDft(float[] inreal, float[] inimag, float[] outreal, float[] outimag) {
89 int n = inreal.length;
90 for (@Parallel int k = 0; k < n; k++) { // For each output element
91 float sumReal = 0;
92 float simImag = 0;
93 for (int t = 0; t < n; t++) { // For each input element
94 float angle = (2 * floatPI() * t * k) / n;
95 sumReal += inreal[t] * cos(angle) + inimag[t] * sin(angle);
96 simImag += -inreal[t] * sin(angle) + inimag[t] * cos(angle);
97 }
98 outreal[k] = sumReal;
99 outimag[k] = simImag;
100 }
101 }
102
103 /**
104 * Execute the Discrete Fourier Transform on a TornadoDevice.
105 *
106 * @param device The TornadoDevice to use.
107 */
108 public void execute(TornadoDevice device) {
109 TaskGraph graph =
110 new TaskGraph("DFT").transferToDevice(EVERY_EXECUTION, inReal, inImag)
111 .task("t0", TornadoDFT::computeDft, inReal, inImag, outReal, outImag)
112 .transferToHost(EVERY_EXECUTION, outReal, outImag);
113
114 ImmutableTaskGraph itg = graph.snapshot();
115 TornadoExecutionPlan executionPlan = new TornadoExecutionPlan(itg);
116 executionPlan.withWarmUp().withDevice(device);
117 time = -System.nanoTime();
118 executionPlan.execute();
119 time += System.nanoTime();
120 }
121
122 /**
123 * Execute the Discrete Fourier Transform on the default TornadoDevice.
124 */
125 public void execute() {
126 TornadoDevice device = TornadoRuntimeProvider.getTornadoRuntime().getDefaultDevice();
127 execute(device);
128 }
129
130 /**
131 * Validate the Discrete Fourier Transform on the default TornadoDevice.
132 *
133 * @param deviceID The device ID to use.
134 */
135 public void validate(int deviceID) {
136 TornadoDevice device = FFXTornado.getDevice(deviceID);
137 validate(device);
138 }
139
140 /**
141 * Validate the Discrete Fourier Transform on a TornadoDevice.
142 *
143 * @param device The TornadoDevice to use.
144 */
145 public void validate(TornadoDevice device) {
146 execute(device);
147
148 long javaTime = -System.nanoTime();
149 computeDft(inReal, inImag, outReal, outImag);
150 javaTime += System.nanoTime();
151
152 System.out.println(" ");
153 FFXTornado.logDevice(device);
154 double speedUp = (double) javaTime / (double) time;
155 System.out.printf(" %12s %8.6f (sec)\n %12s %8.6f (sec) Speed-Up %8.6f%n",
156 " Java", 1.0e-9 * javaTime, " OpenCL", 1.0e-9 * time, speedUp);
157
158 }
159 }