olb::entropicLbHelpers< T, DESCRIPTOR > Struct Template Reference

#include <entropicLbHelpers.h>

Collaboration diagram for olb::entropicLbHelpers< T, DESCRIPTOR >:

Static Public Member Functions
static T	equilibrium (int iPop, T rho, const T u[DESCRIPTOR::d])
	Computation of equilibrium distribution.
static T	equilibriumApprox (int iPop, T rho, const T u[DESCRIPTOR::d])
	Computation of equilibrium distribution.

Detailed Description

template<typename T, typename DESCRIPTOR>
struct olb::entropicLbHelpers< T, DESCRIPTOR >

Definition at line 36 of file entropicLbHelpers.h.

Member Function Documentation

equilibrium()

template<typename T , typename DESCRIPTOR >

static T olb::entropicLbHelpers< T, DESCRIPTOR >::equilibrium ( int iPop, T rho, const T u[DESCRIPTOR::d] )

inlinestatic

Computation of equilibrium distribution.

Definition at line 38 of file entropicLbHelpers.h.

  {
    typedef DESCRIPTOR L;
    const T invCs = util::sqrt(descriptors::invCs2<T,L>());
    const T sqt3 = util::sqrt(3.0);
    T prod = (T)1;
    for (int iD=0; iD < DESCRIPTOR::d; ++iD) {
      T uc = u[iD] * invCs; // u[iD] / c_s
 
      prod *= ((T)2 - util::sqrt(1.0+uc*uc)) *
              util::pow((2.0 / sqt3 * uc +
                         util::sqrt(1.0+uc*uc))/(1.0-uc/sqt3),
                        descriptors::c<L>(iPop,iD)/sqt3*invCs);
    }
    return rho*descriptors::t<T,L>(iPop)*prod-descriptors::t<T,L>(iPop);
  }

References olb::util::pow(), and olb::util::sqrt().

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equilibriumApprox()

template<typename T , typename DESCRIPTOR >

static T olb::entropicLbHelpers< T, DESCRIPTOR >::equilibriumApprox ( int iPop, T rho, const T u[DESCRIPTOR::d] )

inlinestatic

Computation of equilibrium distribution.

Definition at line 56 of file entropicLbHelpers.h.

  {
    typedef DESCRIPTOR L;
 
    T uSqr = util::normSqr<T,L::d>(u);
    T cu = T();
    for (int iD=0; iD < DESCRIPTOR::d; ++iD) {
      cu += descriptors::c<L>(iPop,iD)*u[iD];
    }
 
    return rho * descriptors::t<T,L>(iPop) * (1.0 +
           cu*descriptors::invCs2<T,L>() - 0.5 * uSqr*descriptors::invCs2<T,L>() + 0.5*util::pow(descriptors::invCs2<T,L>(),2)*cu*cu
           - 0.5*util::pow(descriptors::invCs2<T,L>(),2)*cu*uSqr + util::pow(cu,3)*util::pow(descriptors::invCs2<T,L>(),3)/6.0
           + 0.125*uSqr*uSqr*util::pow(descriptors::invCs2<T,L>(),2) - 0.25*cu*cu*uSqr*util::pow(descriptors::invCs2<T,L>(),3)
           + util::pow(cu,4)*util::pow(descriptors::invCs2<T,L>(),4)/24.0)-descriptors::t<T,L>(iPop);
  }

References olb::util::pow().

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The documentation for this struct was generated from the following file:

• src/dynamics/entropicLbHelpers.h