From 03c71534b31c7a81e7f0b8a460c6cea74aad1f1c Mon Sep 17 00:00:00 2001
From: Giovanni Bussi <giovanni.bussi@gmail.com>
Date: Tue, 10 Dec 2013 12:41:06 +0100
Subject: [PATCH] Added documentation to class SwitchingFunction
---
src/tools/SwitchingFunction.h | 56 +++++++++++++++++++++++++++++------
1 file changed, 47 insertions(+), 9 deletions(-)
diff --git a/src/tools/SwitchingFunction.h b/src/tools/SwitchingFunction.h
index 297fb97c5..60fa6bae6 100644
--- a/src/tools/SwitchingFunction.h
+++ b/src/tools/SwitchingFunction.h
@@ -30,29 +30,67 @@ class Log;
class Keywords;
/// \ingroup TOOLBOX
-/// Small class to compure switching functions in the form
-/// In the future we might extend it so as to be set using
-/// a string:
-/// void set(std::string);
-/// which can then be parsed for more complex stuff, e.g. exponentials
-/// tabulated functions from file, matheval, etc...
+/// Small class to compure switching functions.
+/// Switching functions are created using set() and
+/// then can be used with function calculate() or calculateSqr().
+/// Since this is typically computed on a distance vector,
+/// the second all (calculateSqr()) allows to skip the calculation
+/// of a square root in some case, thus potentially increasing
+/// performances.
class SwitchingFunction{
+/// This is to check that switching function has been initialized
bool init;
+/// Type of function
enum {spline,exponential,gaussian,smap} type;
- int nn,mm,a,b;
- double invr0,d0,dmax,c,d;
- double invr0_2,dmax_2;
+/// Inverse of scaling length.
+/// We store the inverse to avoid a division
+ double invr0;
+/// Minimum distance (before this, function is one)
+ double d0;
+/// Maximum distance (after this, function is zero)
+ double dmax;
+/// Exponents for rational function
+ int nn,mm;
+/// Parameters for smap function
+ int a,b;
+ double c,d;
+/// Square of invr0, useful in calculateSqr()
+ double invr0_2;
+/// Square of dmax, useful in calculateSqr()
+ double dmax_2;
+/// Parameters for stretching the function to zero at d_max
double stretch,shift;
+/// Low-level tool to compute rational functions.
+/// It is separated since it is called both by calculate() and calculateSqr()
double do_rational(double rdist,double&dfunc,int nn,int mm)const;
public:
static void registerKeywords( Keywords& keys );
+/// Constructor
SwitchingFunction();
+/// Set a "rational" switching function.
+/// Notice that a d_max is set automatically to a value such that
+/// f(d_max)=0.00001.
void set(int nn,int mm,double r_0,double d_0);
+/// Set an arbitrary switching function.
+/// Parse the string in definition and possibly returns errors
+/// in the errormsg string
void set(const std::string& definition, std::string& errormsg);
+/// Returns a string with a description of the switching function
std::string description() const ;
+/// Compute the switching function.
+/// Returns s(x). df will be set to the value of the derivative
+/// of the switching function _divided_by_x
double calculate(double x,double&df)const;
+/// Compute the switching function.
+/// Returns \f$ s(\sqrt{x})\f$ .
+/// df will be set to the \f$ \frac{1}{\sqrt{x}}\frac{ds}{d\sqrt{x}}= 2 \frac{ds}{dx}\f$
+/// (same as calculate()).
+/// The advantage is that in some case the expensive square root can be avoided
+/// (namely for rational functions, if nn and mm are even and d0 is zero)
double calculateSqr(double distance2,double&dfunc)const;
+/// Returns d0
double get_d0() const;
+/// Returns r0
double get_r0() const;
};
--
GitLab