src/math/tnt_math_utils.hpp

#ifndef MATH_UTILS_H
#define MATH_UTILS_H

/* needed for fabs, sqrt() below */
#include <cmath>


namespace TNT
{
/**
        @returns hypotenuse of real (non-complex) scalars a and b by 
        avoiding underflow/overflow
        using (a * sqrt( 1 + (b/a) * (b/a))), rather than
        sqrt(a*a + b*b).
*/
template <class Real>
Real hypot(const Real &a, const Real &b)
{
        
        if (a== 0)
                return abs(b);
        else
        {
                Real c = b/a;
                return fabs(a) * sqrt(1 + c*c);
        }
}
} /* TNT namespace */


#endif
/* MATH_UTILS_H */
Revision:	1336
Committed:	Tue Apr 7 20:16:26 2009 UTC (16 years ago) by gezelter
File size:	494 byte(s)
Log Message:	adding jama and tnt libraries for various linear algebra routines
#	Content
1	#ifndef MATH_UTILS_H
2	#define MATH_UTILS_H
3
4	/* needed for fabs, sqrt() below */
5	#include <cmath>
6
7
8
9	namespace TNT
10	{
11	/**
12	@returns hypotenuse of real (non-complex) scalars a and b by
13	avoiding underflow/overflow
14	using (a * sqrt( 1 + (b/a) * (b/a))), rather than
15	sqrt(aa + bb).
16	*/
17	template <class Real>
18	Real hypot(const Real &a, const Real &b)
19	{
20
21	if (a== 0)
22	return abs(b);
23	else
24	{
25	Real c = b/a;
26	return fabs(a) * sqrt(1 + c*c);
27	}
28	}
29	} /* TNT namespace */
30
31
32
33	#endif
34	/* MATH_UTILS_H */