src/nonbonded/SwitchingFunction.cpp

/*
 * Copyright (c) 2005 The University of Notre Dame. All Rights Reserved.
 *
 * The University of Notre Dame grants you ("Licensee") a
 * non-exclusive, royalty free, license to use, modify and
 * redistribute this software in source and binary code form, 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 "AS IS," without a warranty of any
 * kind. All express or implied conditions, representations and
 * warranties, including any implied warranty of merchantability,
 * fitness for a particular purpose or non-infringement, are hereby
 * excluded.  The University of Notre Dame and its licensors shall not
 * be liable for any damages suffered by licensee as a result of
 * using, modifying or distributing the software or its
 * derivatives. In no event will the University of Notre Dame or its
 * licensors be liable for any lost revenue, profit or data, or for
 * direct, indirect, special, consequential, incidental or punitive
 * damages, however caused and regardless of the theory of liability,
 * arising out of the use of or inability to use software, even if the
 * University of Notre Dame has been advised of the possibility of
 * such damages.
 *
 * SUPPORT OPEN SCIENCE!  If you use OpenMD or its source code in your
 * research, please cite the appropriate papers when you publish your
 * work.  Good starting points are:
 *                                                                      
 * [1]  Meineke, et al., J. Comp. Chem. 26, 252-271 (2005).             
 * [2]  Fennell & Gezelter, J. Chem. Phys. 124, 234104 (2006).          
 * [3]  Sun, Lin & Gezelter, J. Chem. Phys. 128, 24107 (2008).          
 * [4]  Vardeman & Gezelter, in progress (2009).                        
 */

#include <cmath>
#include <iostream>

#include "nonbonded/SwitchingFunction.hpp"
#include "utils/simError.h"

using namespace std;
namespace OpenMD {

  SwitchingFunction::SwitchingFunction() : np_(150), haveSpline_(false), 
                                           isCubic_(true), functionType_(cubic) {
    switchSpline_ = new CubicSpline();
  }

  void SwitchingFunction::setSwitchType(SwitchingFunctionType sft) {
    if ((sft == fifth_order_poly) || (sft == cubic)) {
      if (haveSpline_) {
        delete switchSpline_;
        switchSpline_ = new CubicSpline();
        setSwitch(rin_, rout_);
      } 
    } else {
      sprintf( painCave.errMsg,
               "SwitchingFunction::setSwitchType was given unknown function type\n");
      painCave.severity = OPENMD_ERROR;
      painCave.isFatal = 1;
      simError();          
    }
  }

  void SwitchingFunction::setSwitch(RealType rinner, RealType router) {
    if (router < rinner) {
          sprintf( painCave.errMsg,
                   "SwitchingFunction::setSwitch was given rinner (%lf) which was\n" 
                   "\tlarger than router (%lf).\n", rinner, router);
          painCave.severity = OPENMD_ERROR;
          painCave.isFatal = 1;
          simError();          
    }
    if (router < 0.0) {
          sprintf( painCave.errMsg,
                   "SwitchingFunction::setSwitch was given router (%lf) which was\n" 
                   "\tless than zero.\n", router);
          painCave.severity = OPENMD_ERROR;
          painCave.isFatal = 1;
          simError();           
    }   
    if (rinner < 0.0) {
          sprintf( painCave.errMsg,
                   "SwitchingFunction::setSwitch was given rinner (%lf) which was\n"
                   "\tless than zero.\n", router);
          painCave.severity = OPENMD_ERROR;
          painCave.isFatal = 1;
          simError();           
    }

    rin_ = rinner;
    rout_ = router;
    rin2_ = rin_ * rin_;
    rout2_ = rout_ * rout_;

    if ((router - rinner) < 1.0e-8) {
      // no reason to set up spline if the switching region is tiny
      return;
    }
    
    // setup r -> sw lookup spline
    if (functionType_ == fifth_order_poly) {
      isCubic_ = false;
      RealType c0 = 1.0;
      RealType c3 = -10.0;
      RealType c4 = 15.0;
      RealType c5 = -6.0;
 
      RealType dx, r, yval, rval, rval2, rval3, rval4, rval5;
      RealType rvaldi, rvaldi2, rvaldi3, rvaldi4, rvaldi5;

      dx = (rout_ - rin_) / RealType(np_-1);

      for (int i = 0; i < np_; i++) {
        r = rin_ + RealType(i)*dx;
        rval = ( r - rin_ );
        rval2 = rval*rval;
        rval3 = rval2*rval;
        rval4 = rval2*rval2;
        rval5 = rval3*rval2;
        rvaldi = 1.0 / ( rout_ - rin_ );
        rvaldi2 = rvaldi*rvaldi;
        rvaldi3 = rvaldi2*rvaldi;
        rvaldi4 = rvaldi2*rvaldi2;
        rvaldi5 = rvaldi3*rvaldi2;
        yval= c0 + c3*rval3*rvaldi3 + c4*rval4*rvaldi4 + c5*rval5*rvaldi5;
        switchSpline_->addPoint(r, yval);
      } 
    } else {
      // cubic splines only need 2 points to do a cubic switching function...
      isCubic_ = true;
      switchSpline_->addPoint(rin_, 1.0);
      switchSpline_->addPoint(rout_, 0.0);
    }
    haveSpline_ = true;
    return;
  }

  bool SwitchingFunction::getSwitch(const RealType &r2, RealType &sw, RealType &dswdr, 
                                    RealType &r) {

    sw = 1.0;
    dswdr = 0.0;

    bool in_switching_region = false;

    if (r2 > rin2_) {
      if (r2 > rout2_) {
        sw = 0.0;
      } else {
        in_switching_region = true;
        r = sqrt(r2);
        pair<RealType, RealType> result = switchSpline_->getValueAndDerivativeAt(r);
        sw = result.first;
        dswdr = result.second;
      }
    }
    return in_switching_region;
  }
}
Revision:	1536
Committed:	Wed Jan 5 14:49:05 2011 UTC (14 years, 4 months ago) by gezelter
File size:	5910 byte(s)
Log Message:	compiles, builds and runs, but is very slow
#	User	Rev	Content
1	gezelter	1530	/*
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			* 1. Redistributions of source code must retain the above copyright
10			* notice, this list of conditions and the following disclaimer.
11			*
12			* 2. Redistributions in binary form must reproduce the above copyright
13			* 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			*
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			* [4] Vardeman & Gezelter, in progress (2009).
40			*/
41
42			#include <cmath>
43	gezelter	1536	#include <iostream>
44	gezelter	1530
45			#include "nonbonded/SwitchingFunction.hpp"
46			#include "utils/simError.h"
47
48			using namespace std;
49			namespace OpenMD {
50
51			SwitchingFunction::SwitchingFunction() : np_(150), haveSpline_(false),
52	gezelter	1536	isCubic_(true), functionType_(cubic) {
53			switchSpline_ = new CubicSpline();
54			}
55	gezelter	1530
56			void SwitchingFunction::setSwitchType(SwitchingFunctionType sft) {
57			if ((sft == fifth_order_poly) \|\| (sft == cubic)) {
58			if (haveSpline_) {
59			delete switchSpline_;
60	gezelter	1536	switchSpline_ = new CubicSpline();
61	gezelter	1530	setSwitch(rin_, rout_);
62			}
63			} else {
64			sprintf( painCave.errMsg,
65			"SwitchingFunction::setSwitchType was given unknown function type\n");
66			painCave.severity = OPENMD_ERROR;
67			painCave.isFatal = 1;
68			simError();
69			}
70			}
71
72			void SwitchingFunction::setSwitch(RealType rinner, RealType router) {
73			if (router < rinner) {
74			sprintf( painCave.errMsg,
75			"SwitchingFunction::setSwitch was given rinner (%lf) which was\n"
76			"\tlarger than router (%lf).\n", rinner, router);
77			painCave.severity = OPENMD_ERROR;
78			painCave.isFatal = 1;
79			simError();
80			}
81			if (router < 0.0) {
82			sprintf( painCave.errMsg,
83			"SwitchingFunction::setSwitch was given router (%lf) which was\n"
84			"\tless than zero.\n", router);
85			painCave.severity = OPENMD_ERROR;
86			painCave.isFatal = 1;
87			simError();
88			}
89			if (rinner < 0.0) {
90			sprintf( painCave.errMsg,
91			"SwitchingFunction::setSwitch was given rinner (%lf) which was\n"
92			"\tless than zero.\n", router);
93			painCave.severity = OPENMD_ERROR;
94			painCave.isFatal = 1;
95			simError();
96			}
97
98			rin_ = rinner;
99			rout_ = router;
100			rin2_ = rin_ * rin_;
101			rout2_ = rout_ * rout_;
102
103			if ((router - rinner) < 1.0e-8) {
104			// no reason to set up spline if the switching region is tiny
105			return;
106			}
107
108			// setup r -> sw lookup spline
109			if (functionType_ == fifth_order_poly) {
110			isCubic_ = false;
111			RealType c0 = 1.0;
112			RealType c3 = -10.0;
113			RealType c4 = 15.0;
114			RealType c5 = -6.0;
115
116			RealType dx, r, yval, rval, rval2, rval3, rval4, rval5;
117			RealType rvaldi, rvaldi2, rvaldi3, rvaldi4, rvaldi5;
118
119			dx = (rout_ - rin_) / RealType(np_-1);
120
121			for (int i = 0; i < np_; i++) {
122			r = rin_ + RealType(i)*dx;
123			rval = ( r - rin_ );
124			rval2 = rval*rval;
125			rval3 = rval2*rval;
126			rval4 = rval2*rval2;
127			rval5 = rval3*rval2;
128			rvaldi = 1.0 / ( rout_ - rin_ );
129			rvaldi2 = rvaldi*rvaldi;
130			rvaldi3 = rvaldi2*rvaldi;
131			rvaldi4 = rvaldi2*rvaldi2;
132			rvaldi5 = rvaldi3*rvaldi2;
133			yval= c0 + c3rval3rvaldi3 + c4rval4rvaldi4 + c5rval5rvaldi5;
134			switchSpline_->addPoint(r, yval);
135			}
136			} else {
137			// cubic splines only need 2 points to do a cubic switching function...
138			isCubic_ = true;
139			switchSpline_->addPoint(rin_, 1.0);
140			switchSpline_->addPoint(rout_, 0.0);
141			}
142			haveSpline_ = true;
143			return;
144			}
145
146	gezelter	1536	bool SwitchingFunction::getSwitch(const RealType &r2, RealType &sw, RealType &dswdr,
147			RealType &r) {
148
149	gezelter	1530	sw = 1.0;
150			dswdr = 0.0;
151	gezelter	1536
152	gezelter	1530	bool in_switching_region = false;
153
154			if (r2 > rin2_) {
155			if (r2 > rout2_) {
156			sw = 0.0;
157			} else {
158			in_switching_region = true;
159			r = sqrt(r2);
160			pair<RealType, RealType> result = switchSpline_->getValueAndDerivativeAt(r);
161			sw = result.first;
162			dswdr = result.second;
163			}
164			}
165	gezelter	1536	return in_switching_region;
166	gezelter	1530	}
167			}