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Implemented dDelta3; test passes

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Signed-off-by: Ian Bell <ian.h.bell@gmail.com>
This commit is contained in:
Ian Bell
2014-06-01 19:46:30 +02:00
parent c468339768
commit 3168f15efc
2 changed files with 21 additions and 1 deletions
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20
src/Helmholtz.cpp
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@@ -577,6 +577,26 @@ long double ResidualHelmholtzGERG2008Gaussian::dDelta2(const long double &tau, c
}
return std::accumulate(s.begin(), s.end(), 0.0);
};
long double ResidualHelmholtzGERG2008Gaussian::dDelta3(const long double &tau, const long double &delta) throw()
{
/**
Term derived in sympy using
from sympy import *
n_i, d_i, t_i, tau, delta, eta, gamma, beta, epsilon = symbols('n_i, d_i, t_i, tau, delta, eta, gamma, beta, epsilon')
psi = exp(-eta*(delta-epsilon)**2-beta*(delta-gamma))
I = n_i*delta**d_i*tau**t_i*psi
ccode(simplify(diff(I,delta,3)))
*/
for (std::size_t i=0; i<N; ++i)
{
ResidualHelmholtzGaussianElement &el = elements[i];
long double psi=exp(-el.eta*pow(delta-el.epsilon,2)-el.beta*(delta-el.gamma));
s[i] = el.n*pow(tau,el.t)*pow(delta,el.d-3)*psi*(3*el.d*pow(delta, 2)*(-2*el.eta + pow(el.beta + 2*el.eta*(delta - el.epsilon), 2)) + 3*el.d*delta*(el.beta - el.d*(el.beta + 2*el.eta*(delta - el.epsilon)) + 2*el.eta*(delta - el.epsilon)) + el.d*(pow(el.d, 2) - 3*el.d + 2) + pow(delta, 3)*(el.beta + 2*el.eta*(delta - el.epsilon))*(6*el.eta - pow(el.beta + 2*el.eta*(delta - el.epsilon), 2)));
}
return std::accumulate(s.begin(), s.end(), 0.0);
};
long double ResidualHelmholtzGERG2008Gaussian::dDelta_dTau(const long double &tau, const long double &delta) throw()
{
for (std::size_t i=0; i<N; ++i)