mirror of
https://github.com/NGSolve/netgen.git
synced 2024-12-26 05:50:32 +05:00
112 lines
2.2 KiB
C++
112 lines
2.2 KiB
C++
#include <mystdlib.h>
|
|
|
|
#include <myadt.hpp>
|
|
#include <gprim.hpp>
|
|
|
|
namespace netgen
|
|
{
|
|
|
|
/*
|
|
// template <>
|
|
inline void CalcInverse (const Mat<2,2> & m, Mat<2,2> & inv)
|
|
{
|
|
double det = m(0,0) * m(1,1) - m(0,1) * m(1,0);
|
|
if (det == 0)
|
|
{
|
|
inv = 0;
|
|
return;
|
|
}
|
|
|
|
double idet = 1.0 / det;
|
|
inv(0,0) = idet * m(1,1);
|
|
inv(0,1) = -idet * m(0,1);
|
|
inv(1,0) = -idet * m(1,0);
|
|
inv(1,1) = idet * m(0,0);
|
|
}
|
|
*/
|
|
|
|
|
|
|
|
// template <>
|
|
void CalcInverse (const Mat<3,3> & m, Mat<3,3> & inv)
|
|
{
|
|
double det = Det (m);
|
|
if (det == 0)
|
|
{
|
|
inv = 0;
|
|
return;
|
|
}
|
|
|
|
double idet = 1.0 / det;
|
|
inv(0,0) = idet * (m(1,1) * m(2,2) - m(1,2) * m(2,1));
|
|
inv(1,0) = -idet * (m(1,0) * m(2,2) - m(1,2) * m(2,0));
|
|
inv(2,0) = idet * (m(1,0) * m(2,1) - m(1,1) * m(2,0));
|
|
|
|
inv(0,1) = -idet * (m(0,1) * m(2,2) - m(0,2) * m(2,1));
|
|
inv(1,1) = idet * (m(0,0) * m(2,2) - m(0,2) * m(2,0));
|
|
inv(2,1) = -idet * (m(0,0) * m(2,1) - m(0,1) * m(2,0));
|
|
|
|
inv(0,2) = idet * (m(0,1) * m(1,2) - m(0,2) * m(1,1));
|
|
inv(1,2) = -idet * (m(0,0) * m(1,2) - m(0,2) * m(1,0));
|
|
inv(2,2) = idet * (m(0,0) * m(1,1) - m(0,1) * m(1,0));
|
|
}
|
|
|
|
/*
|
|
// template <>
|
|
void CalcInverse (const Mat<2,3> & m, Mat<3,2> & inv)
|
|
{
|
|
Mat<2,2> a = m * Trans (m);
|
|
Mat<2,2> ainv;
|
|
CalcInverse (a, ainv);
|
|
inv = Trans (m) * ainv;
|
|
}
|
|
*/
|
|
|
|
|
|
|
|
double Det (const Mat<2,2> & m)
|
|
{
|
|
return m(0,0) * m(1,1) - m(0,1) * m(1,0);
|
|
}
|
|
|
|
double Det (const Mat<3,3> & m)
|
|
{
|
|
return
|
|
m(0,0) * m(1,1) * m(2,2)
|
|
+ m(1,0) * m(2,1) * m(0,2)
|
|
+ m(2,0) * m(0,1) * m(1,2)
|
|
- m(0,0) * m(2,1) * m(1,2)
|
|
- m(1,0) * m(0,1) * m(2,2)
|
|
- m(2,0) * m(1,1) * m(0,2);
|
|
}
|
|
|
|
|
|
void EigenValues (const Mat<3,3> & m, Vec<3> & ev)
|
|
{
|
|
const double pi = 3.141592;
|
|
double a, b, c, d;
|
|
double p, q;
|
|
double arg;
|
|
|
|
a = -1.;
|
|
b = m(0,0) + m(1,1) + m(2,2);
|
|
c = -( m(0,0)*m(2,2) + m(1,1)*m(2,2) + m(0,0)*m(1,1) - sqr(m(0,1)) - sqr(m(0,2)) - sqr(m(1,2)) );
|
|
d = Det (m);
|
|
p = 3.*a*c - sqr(b);
|
|
q = 27.*sqr(a)*d - 9.*a*b*c + 2.*sqr(b)*b;
|
|
|
|
|
|
arg = acos((-q/2)/sqrt(-(p*p*p)));
|
|
|
|
|
|
ev(0) = (2. * sqrt(-p) * cos(arg/3.) - b) / 3.*a;
|
|
ev(1) = (-2. * sqrt(-p) * cos(arg/3.+pi/3) - b) / 3.*a;
|
|
ev(2) = (-2. * sqrt(-p) * cos(arg/3.-pi/3)- b) / 3.*a;
|
|
|
|
|
|
|
|
}
|
|
|
|
|
|
}
|