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lammps/lib/atc/XT_Function.h
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XT_Function.h
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#ifndef XT_FUNCTION_H
#define XT_FUNCTION_H
#include <math.h>
#include <string>
#include <vector>
#include <cstdlib>
using namespace std;
namespace ATC {
//------------------------------------------------------------------------
// base class
//------------------------------------------------------------------------
class XT_Function {
public:
XT_Function(int nargs, double* args);
~XT_Function(void) {};
const string & get_tag() { return tag;}
/** function value */
virtual inline double f(double* x, double t) {return 0.0;};
/** time derivative of function */
virtual inline double dfdt(double* x, double t) {return 0.0;};
/** 2nd time derivative of funtion */
virtual inline double ddfdt(double* x, double t) {return 0.0;};
/** 3rd time derivative of funtion */
virtual inline double dddfdt(double* x, double t) {return 0.0;};
protected:
/** mask : masks x,y,z dependence, x0 : origin */
double mask[3], x0[3];
/** tag : name of function */
string tag;
};
//------------------------------------------------------------------------
// manager
//------------------------------------------------------------------------
class XT_Function_Mgr {
public:
/** Static instance of this class */
static XT_Function_Mgr * instance();
XT_Function* get_function(string & type, int nargs, double * arg);
XT_Function* get_function(char ** arg, int nargs);
XT_Function* get_constant_function(double c);
XT_Function* copy_XT_function(XT_Function* other);
protected:
XT_Function_Mgr() {};
~XT_Function_Mgr();
/** Vector of ptrs to functions created thus far */
std::vector<XT_Function *> xtFunctionVec_;
private:
static XT_Function_Mgr * myInstance_;
};
//------------------------------------------------------------------------
// derived classes
//------------------------------------------------------------------------
/** a constant */
class ConstantFunction : public XT_Function {
public:
ConstantFunction(int nargs, double* args);
~ConstantFunction(void) {};
inline double f(double* x, double t)
{return C0;};
private :
double C0;
};
/** a linear in x-y-z */
class LinearFunction : public XT_Function {
public:
LinearFunction(int nargs, double* args);
~LinearFunction(void) {};
inline double f(double* x, double t)
{return mask[0]*(x[0]-x0[0])+mask[1]*(x[1]-x0[1])+mask[2]*(x[2]-x0[2]) + C0;};
private :
double C0;
};
/** a quadratic in x-y-z */
class QuadraticFunction : public XT_Function {
public:
QuadraticFunction(int nargs, double* args);
~QuadraticFunction(void) {};
inline double f(double* x, double t)
{return
C2[0]*(x[0]-x0[0])*(x[0]-x0[0])+
C2[1]*(x[1]-x0[1])*(x[1]-x0[1])+
C2[2]*(x[2]-x0[2])*(x[2]-x0[2])+
2.0*C2[3]*(x[0]-x0[0])*(x[1]-x0[1]) +
2.0*C2[4]*(x[0]-x0[0])*(x[2]-x0[2]) +
2.0*C2[5]*(x[1]-x0[1])*(x[2]-x0[2]) +
mask[0]*(x[0]-x0[0])+mask[1]*(x[1]-x0[1])+mask[2]*(x[2]-x0[2]) + C0;};
private :
double C0, C2[6]; // C2 1:xx 2:yy 3:zz 4:xy|yx 5:xz|zx 6:yz|zy
};
class SineFunction : public XT_Function {
public:
SineFunction(int nargs, double* args);
~SineFunction(void);
inline double f(double* x, double t)
{return C*sin( mask[0]*(x[0]-x0[0])
+mask[1]*(x[1]-x0[1])
+mask[2]*(x[2]-x0[2]) - w*t);};
private :
double C, w;
};
/** a spatial gaussian function */
class GaussianFunction : public XT_Function {
public:
GaussianFunction(int nargs, double* args);
~GaussianFunction(void){};
// 1/(2 pi \sigma)^(n/2) exp(-1/2 x.x/\sigma^2 ) for n = dimension
inline double f(double* x, double t)
{return C*exp(-(mask[0]*(x[0]-x0[0])*(x[0]-x0[0])
+mask[1]*(x[1]-x0[1])*(x[1]-x0[1])
+mask[2]*(x[2]-x0[2])*(x[2]-x0[2]))/tau/tau) + C0;};
protected:
double tau, C, C0;
};
/** a spatial gaussian function that has variables ramp up in time */
class GaussianTemporalRamp : public GaussianFunction {
public:
GaussianTemporalRamp(int nargs, double* args);
~GaussianTemporalRamp(void){};
double f(double* x, double t);
double dfdt(double* x, double t);
protected:
double tau_initial, tau_slope;
double C_initial, C_slope;
double C0_initial, C0_slope;
};
/** a ramp in time */
class TemporalRamp : public XT_Function {
public:
TemporalRamp(int nargs, double* args);
~TemporalRamp(void) {};
inline double f(double* x, double t)
{return f_initial + slope*t;};
inline double dfdt(double* x, double t)
{return slope;};
private :
double f_initial, slope;
};
}
#endif
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