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git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@15547 f3b2605a-c512-4ea7-a41b-209d697bcdaa

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sjplimp
2016-09-06 21:55:39 +00:00
parent f9c106897f
commit 56945a56aa
2 changed files with 122 additions and 64 deletions
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115
src/compute_omega_chunk.cpp
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@ -18,11 +18,14 @@
#include "modify.h"
#include "compute_chunk_atom.h"
#include "domain.h"
#include "math_extra.h"
#include "memory.h"
#include "error.h"
using namespace LAMMPS_NS;
#define EPSILON 1.0e-6
/* ---------------------------------------------------------------------- */
ComputeOmegaChunk::ComputeOmegaChunk(LAMMPS *lmp, int narg, char **arg) :
@ -192,49 +195,97 @@ void ComputeOmegaChunk::compute_array()
MPI_Allreduce(&angmom[0][0],&angmomall[0][0],3*nchunk,
MPI_DOUBLE,MPI_SUM,world);
// compute omega for each chunk from L = Iw, inverting I to solve for w
// compute omega for each chunk
double ione[3][3],inverse[3][3];
double determinant,invdeterminant;
double idiag[3],ex[3],ey[3],ez[3],cross[3];
double ione[3][3],inverse[3][3],evectors[3][3];
double *iall,*mall;
for (m = 0; m < nchunk; m++) {
ione[0][0] = inertiaall[m][0];
ione[1][1] = inertiaall[m][1];
ione[2][2] = inertiaall[m][2];
ione[0][1] = inertiaall[m][3];
ione[1][2] = inertiaall[m][4];
ione[0][2] = inertiaall[m][5];
ione[1][0] = ione[0][1];
ione[2][1] = ione[1][2];
ione[2][0] = ione[0][2];
inverse[0][0] = ione[1][1]*ione[2][2] - ione[1][2]*ione[2][1];
inverse[0][1] = -(ione[0][1]*ione[2][2] - ione[0][2]*ione[2][1]);
inverse[0][2] = ione[0][1]*ione[1][2] - ione[0][2]*ione[1][1];
// determinant = triple product of rows of inertia matrix
inverse[1][0] = -(ione[1][0]*ione[2][2] - ione[1][2]*ione[2][0]);
inverse[1][1] = ione[0][0]*ione[2][2] - ione[0][2]*ione[2][0];
inverse[1][2] = -(ione[0][0]*ione[1][2] - ione[0][2]*ione[1][0]);
iall = &inertiaall[m][0];
determinant = iall[0] * (iall[1]*iall[2] - iall[4]*iall[4]) +
iall[3] * (iall[4]*iall[5] - iall[3]*iall[2]) +
iall[5] * (iall[3]*iall[4] - iall[1]*iall[5]);
inverse[2][0] = ione[1][0]*ione[2][1] - ione[1][1]*ione[2][0];
inverse[2][1] = -(ione[0][0]*ione[2][1] - ione[0][1]*ione[2][0]);
inverse[2][2] = ione[0][0]*ione[1][1] - ione[0][1]*ione[1][0];
ione[0][0] = iall[0];
ione[1][1] = iall[1];
ione[2][2] = iall[2];
ione[0][1] = ione[1][0] = iall[3];
ione[1][2] = ione[2][1] = iall[4];
ione[0][2] = ione[2][0] = iall[5];
double determinant = ione[0][0]*ione[1][1]*ione[2][2] +
ione[0][1]*ione[1][2]*ione[2][0] + ione[0][2]*ione[1][0]*ione[2][1] -
ione[0][0]*ione[1][2]*ione[2][1] - ione[0][1]*ione[1][0]*ione[2][2] -
ione[2][0]*ione[1][1]*ione[0][2];
// non-singular I matrix
// use L = Iw, inverting I to solve for w
if (determinant > 0.0)
if (determinant > EPSILON) {
inverse[0][0] = ione[1][1]*ione[2][2] - ione[1][2]*ione[2][1];
inverse[0][1] = -(ione[0][1]*ione[2][2] - ione[0][2]*ione[2][1]);
inverse[0][2] = ione[0][1]*ione[1][2] - ione[0][2]*ione[1][1];
inverse[1][0] = -(ione[1][0]*ione[2][2] - ione[1][2]*ione[2][0]);
inverse[1][1] = ione[0][0]*ione[2][2] - ione[0][2]*ione[2][0];
inverse[1][2] = -(ione[0][0]*ione[1][2] - ione[0][2]*ione[1][0]);
inverse[2][0] = ione[1][0]*ione[2][1] - ione[1][1]*ione[2][0];
inverse[2][1] = -(ione[0][0]*ione[2][1] - ione[0][1]*ione[2][0]);
inverse[2][2] = ione[0][0]*ione[1][1] - ione[0][1]*ione[1][0];
invdeterminant = 1.0/determinant;
for (i = 0; i < 3; i++)
for (j = 0; j < 3; j++)
inverse[i][j] /= determinant;
inverse[i][j] *= invdeterminant;
mall = &angmomall[m][0];
omega[m][0] = inverse[0][0]*mall[0] + inverse[0][1]*mall[1] +
inverse[0][2]*mall[2];
omega[m][1] = inverse[1][0]*mall[0] + inverse[1][1]*mall[1] +
inverse[1][2]*mall[2];
omega[m][2] = inverse[2][0]*mall[0] + inverse[2][1]*mall[1] +
inverse[2][2]*mall[2];
omega[m][0] = inverse[0][0]*angmom[m][0] + inverse[0][1]*angmom[m][1] +
inverse[0][2]*angmom[m][2];
omega[m][1] = inverse[1][0]*angmom[m][0] + inverse[1][1]*angmom[m][1] +
inverse[1][2]*angmom[m][2];
omega[m][2] = inverse[2][0]*angmom[m][0] + inverse[2][1]*angmom[m][1] +
inverse[2][2]*angmom[i][2];
// handle each (nearly) singular I matrix
// due to 2-atom chunk or linear molecule
// use jacobi() and angmom_to_omega() to calculate valid omega
} else {
int ierror = MathExtra::jacobi(ione,idiag,evectors);
if (ierror) error->all(FLERR,
"Insufficient Jacobi rotations for omega/chunk");
ex[0] = evectors[0][0];
ex[1] = evectors[1][0];
ex[2] = evectors[2][0];
ey[0] = evectors[0][1];
ey[1] = evectors[1][1];
ey[2] = evectors[2][1];
ez[0] = evectors[0][2];
ez[1] = evectors[1][2];
ez[2] = evectors[2][2];
// enforce 3 evectors as a right-handed coordinate system
// flip 3rd vector if needed
MathExtra::cross3(ex,ey,cross);
if (MathExtra::dot3(cross,ez) < 0.0) MathExtra::negate3(ez);
// if any principal moment < scaled EPSILON, set to 0.0
double max;
max = MAX(idiag[0],idiag[1]);
max = MAX(max,idiag[2]);
if (idiag[0] < EPSILON*max) idiag[0] = 0.0;
if (idiag[1] < EPSILON*max) idiag[1] = 0.0;
if (idiag[2] < EPSILON*max) idiag[2] = 0.0;
// calculate omega using diagonalized inertia matrix
MathExtra::angmom_to_omega(&angmomall[m][0],ex,ey,ez,idiag,&omega[m][0]);
}
}
}