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root/OpenMD/branches/development/src/math/SphericalHarmonic.cpp
Revision: 1665
Committed: Tue Nov 22 20:38:56 2011 UTC (13 years, 5 months ago) by gezelter
File size: 8954 byte(s)
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updated copyright notices

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# User Rev Content
1 gezelter 1042 /*
2     * Copyright (c) 2005 The University of Notre Dame. All Rights Reserved.
3     *
4     * The University of Notre Dame grants you ("Licensee") a
5     * non-exclusive, royalty free, license to use, modify and
6     * redistribute this software in source and binary code form, provided
7     * that the following conditions are met:
8     *
9 gezelter 1390 * 1. Redistributions of source code must retain the above copyright
10 gezelter 1042 * notice, this list of conditions and the following disclaimer.
11     *
12 gezelter 1390 * 2. Redistributions in binary form must reproduce the above copyright
13 gezelter 1042 * notice, this list of conditions and the following disclaimer in the
14     * documentation and/or other materials provided with the
15     * distribution.
16     *
17     * This software is provided "AS IS," without a warranty of any
18     * kind. All express or implied conditions, representations and
19     * warranties, including any implied warranty of merchantability,
20     * fitness for a particular purpose or non-infringement, are hereby
21     * excluded. The University of Notre Dame and its licensors shall not
22     * be liable for any damages suffered by licensee as a result of
23     * using, modifying or distributing the software or its
24     * derivatives. In no event will the University of Notre Dame or its
25     * licensors be liable for any lost revenue, profit or data, or for
26     * direct, indirect, special, consequential, incidental or punitive
27     * damages, however caused and regardless of the theory of liability,
28     * arising out of the use of or inability to use software, even if the
29     * University of Notre Dame has been advised of the possibility of
30     * such damages.
31 gezelter 1390 *
32     * SUPPORT OPEN SCIENCE! If you use OpenMD or its source code in your
33     * research, please cite the appropriate papers when you publish your
34     * work. Good starting points are:
35     *
36     * [1] Meineke, et al., J. Comp. Chem. 26, 252-271 (2005).
37     * [2] Fennell & Gezelter, J. Chem. Phys. 124, 234104 (2006).
38     * [3] Sun, Lin & Gezelter, J. Chem. Phys. 128, 24107 (2008).
39 gezelter 1665 * [4] Kuang & Gezelter, J. Chem. Phys. 133, 164101 (2010).
40     * [5] Vardeman, Stocker & Gezelter, J. Chem. Theory Comput. 7, 834 (2011).
41 gezelter 1042 */
42    
43     #include <stdio.h>
44 gezelter 1051 #include <cmath>
45 gezelter 1042 #include <limits>
46     #include "math/SphericalHarmonic.hpp"
47     #include "utils/simError.h"
48    
49 gezelter 1390 using namespace OpenMD;
50 gezelter 1042
51     SphericalHarmonic::SphericalHarmonic() {
52     }
53    
54     ComplexType SphericalHarmonic::getValueAt(RealType costheta, RealType phi) {
55    
56     RealType p;
57    
58     // associated Legendre polynomial
59 gezelter 1043 p = Ptilde(L, M, costheta);
60     ComplexType phase(0.0, (RealType)M * phi);
61    
62     return exp(phase) * (ComplexType)p;
63 gezelter 1042
64     }
65     //
66 gezelter 1043 // Routine to calculate the associated Legendre polynomials for m>=0
67 gezelter 1042 //
68 gezelter 1043 RealType SphericalHarmonic::LegendreP(int l,int m, RealType x) {
69    
70     RealType temp1, temp2, temp3, temp4, result;
71     RealType temp5;
72     int i, ll;
73    
74     if (fabs(x) > 1.0) {
75     printf("LegendreP: x out of range: l = %d\tm = %d\tx = %lf\n", l, m, x);
76 gezelter 1042 return std::numeric_limits <RealType>:: quiet_NaN();
77     }
78    
79 gezelter 1043 if (m>l) {
80     printf("LegendreP: m > l: l = %d\tm = %d\tx = %lf\n", l, m, x);
81     return std::numeric_limits <RealType>:: quiet_NaN();
82 gezelter 1042 }
83 gezelter 1043
84     if (m<0) {
85     printf("LegendreP: m < 0: l = %d\tm = %d\tx = %lf\n", l, m, x);
86     return std::numeric_limits <RealType>:: quiet_NaN();
87     } else {
88     temp3=1.0;
89    
90     if (m>0) {
91     temp1=sqrt(1.0-pow(x,2));
92     temp5 = 1.0;
93     for (i=1;i<=m;++i) {
94     temp3 *= -temp5*temp1;
95     temp5 += 2.0;
96 gezelter 1042 }
97     }
98 gezelter 1043 if (l==m) {
99     result = temp3;
100     } else {
101     temp4=x*(2.*m+1.)*temp3;
102     if (l==(m+1)) {
103     result = temp4;
104     } else {
105     for (ll=(m+2);ll<=l;++ll) {
106     temp2 = (x*(2.*ll-1.)*temp4-(ll+m-1.)*temp3)/(RealType)(ll-m);
107     temp3=temp4;
108     temp4=temp2;
109     }
110     result = temp2;
111     }
112     }
113 gezelter 1042 }
114 gezelter 1043 return result;
115 gezelter 1042 }
116    
117 gezelter 1043
118 gezelter 1042 //
119     // Routine to calculate the associated Legendre polynomials for all m...
120     //
121     RealType SphericalHarmonic::Legendre(int l, int m, RealType x) {
122     RealType result;
123     if ( m>l || m <-l ) {
124     printf("Legendre got a bad argument: l = %d\tm = %d\tx = %lf\n", l, m, x);
125     return std::numeric_limits <RealType>:: quiet_NaN();
126     } else if (m >= 0) {
127     result = LegendreP(l,m,x);
128     } else {
129 gezelter 1043 //result = mpow(-m)*LegendreP(l,-m,x);
130 gezelter 1042 result = mpow(-m)*Fact(l+m)/Fact(l-m)*LegendreP(l, -m, x);
131     }
132     result *=mpow(m);
133     return result;
134     }
135     //
136 gezelter 1043 // Routine to calculate the normalized associated Legendre polynomials...
137     //
138     RealType SphericalHarmonic::Ptilde(int l,int m, RealType x){
139    
140     RealType result;
141     if (m>l || m<-l) {
142     result = 0.;
143     } else {
144     RealType y=(RealType)(2.*l+1.)*Fact(l-m)/Fact(l+m);
145 gezelter 1051 result = mpow(m) * sqrt(y) * Legendre(l,m,x) / sqrt(4.0*M_PI);
146 gezelter 1043 }
147     return result;
148     }
149     //
150 gezelter 1042 // mpow returns (-1)**m
151     //
152     RealType SphericalHarmonic::mpow(int m) {
153     int result;
154     if (m<0) m=-m;
155     if (m & 0x1) result = -1;
156     else result = 1;
157     return result;
158     }
159     //
160     // factorial_list is a lookup table for n!
161     //
162     static RealType factorial_list[171]=
163     {1.,1.,2.,6.,24.,120.,720.,5040.,40320.,362880.,3.6288e6,3.99168e7,4.790016e8,6.2270208e9,
164     8.71782912e10,1.307674368e12,2.0922789888e13,3.55687428096e14,6.402373705728e15,
165     1.21645100408832e17,
166     2.43290200817664e18,5.109094217170944e19,1.1240007277776077e21,2.585201673888498e22,
167     6.204484017332394e23,1.5511210043330986e25,4.0329146112660565e26,1.0888869450418352e28,
168     3.0488834461171387e29,8.841761993739702e30,2.6525285981219107e32,8.222838654177922e33,
169     2.631308369336935e35,8.683317618811886e36,2.9523279903960416e38,1.0333147966386145e40,
170     3.7199332678990125e41,1.3763753091226346e43,5.230226174666011e44,2.0397882081197444e46,
171     8.159152832478977e47,3.345252661316381e49,1.40500611775288e51,6.041526306337383e52,
172     2.658271574788449e54,1.1962222086548019e56,5.502622159812089e57,2.5862324151116818e59,
173     1.2413915592536073e61,6.082818640342675e62,3.0414093201713376e64,1.5511187532873822e66,
174     8.065817517094388e67,4.2748832840600255e69,2.308436973392414e71,1.2696403353658276e73,
175     7.109985878048635e74,4.0526919504877214e76,2.3505613312828785e78,1.3868311854568984e80,
176     8.32098711274139e81,5.075802138772248e83,3.146997326038794e85,1.98260831540444e87,
177     1.2688693218588417e89,8.247650592082472e90,5.443449390774431e92,3.647111091818868e94,
178     2.4800355424368305e96,1.711224524281413e98,1.1978571669969892e100,8.504785885678623e101,
179     6.1234458376886085e103,4.4701154615126844e105,3.307885441519386e107,2.48091408113954e109,
180     1.8854947016660504e111,1.4518309202828587e113,1.1324281178206297e115,8.946182130782976e116,
181     7.156945704626381e118,5.797126020747368e120,4.753643337012842e122,3.945523969720659e124,
182     3.314240134565353e126,2.81710411438055e128,2.4227095383672734e130,2.107757298379528e132,
183     1.8548264225739844e134,1.650795516090846e136,1.4857159644817615e138,1.352001527678403e140,
184     1.2438414054641308e142,1.1567725070816416e144,1.087366156656743e146,1.032997848823906e148,
185     9.916779348709496e149,9.619275968248212e151,9.426890448883248e153,9.332621544394415e155,
186     9.332621544394415e157,9.42594775983836e159,9.614466715035127e161,9.90290071648618e163,
187     1.0299016745145628e166,1.081396758240291e168,1.1462805637347084e170,1.226520203196138e172,
188     1.324641819451829e174,1.4438595832024937e176,1.588245541522743e178,1.7629525510902446e180,
189     1.974506857221074e182,2.2311927486598138e184,2.5435597334721877e186,2.925093693493016e188,
190     3.393108684451898e190,3.969937160808721e192,4.684525849754291e194,5.574585761207606e196,
191     6.689502913449127e198,8.094298525273444e200,9.875044200833601e202,1.214630436702533e205,
192     1.506141741511141e207,1.882677176888926e209,2.372173242880047e211,3.0126600184576594e213,
193     3.856204823625804e215,4.974504222477287e217,6.466855489220474e219,8.47158069087882e221,
194     1.1182486511960043e224,1.4872707060906857e226,1.9929427461615188e228,2.6904727073180504e230,
195     3.659042881952549e232,5.012888748274992e234,6.917786472619489e236,9.615723196941089e238,
196     1.3462012475717526e241,1.898143759076171e243,2.695364137888163e245,3.854370717180073e247,
197     5.5502938327393044e249,8.047926057471992e251,1.1749972043909107e254,1.727245890454639e256,
198     2.5563239178728654e258,3.80892263763057e260,5.713383956445855e262,8.62720977423324e264,
199     1.3113358856834524e267,2.0063439050956823e269,3.0897696138473508e271,4.789142901463394e273,
200     7.471062926282894e275,1.1729568794264145e278,1.853271869493735e280,2.9467022724950384e282,
201     4.7147236359920616e284,7.590705053947219e286,1.2296942187394494e289,2.0044015765453026e291,
202     3.287218585534296e293,5.423910666131589e295,9.003691705778438e297,1.503616514864999e300,
203     2.5260757449731984e302,4.269068009004705e304,7.257415615307999e306};
204    
205     //
206     // Routine to return the factorial of j
207     //
208     RealType SphericalHarmonic::Fact(int j) {
209     if (j <= 170 && j>=0) return factorial_list[j];
210    
211     sprintf( painCave.errMsg,
212     "Fact(j) for j >= 171\n");
213     painCave.isFatal = 0;
214     simError();
215     return 0.;
216     }

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