diff options
Diffstat (limited to 'src/cell.c')
| -rw-r--r-- | src/cell.c | 30 |
1 files changed, 30 insertions, 0 deletions
@@ -206,3 +206,33 @@ void cell_get_reciprocal(UnitCell *cell, *bsz = gsl_matrix_get(inv, 2, 1); *csz = gsl_matrix_get(inv, 2, 2); } + + +double resolution(UnitCell *cell, signed int h, signed int k, signed int l) +{ + const double a = cell->a; + const double b = cell->b; + const double c = cell->c; + const double alpha = cell->alpha; + const double beta = cell->beta; + const double gamma = cell->gamma; + + const double Vsq = a*a*b*b*c*c*(1 - cos(alpha)*cos(alpha) + - cos(beta)*cos(beta) + - cos(gamma)*cos(gamma) + + 2*cos(alpha)*cos(beta)*cos(gamma) ); + + const double S11 = b*b*c*c*sin(alpha)*sin(alpha); + const double S22 = a*a*c*c*sin(beta)*sin(beta); + const double S33 = a*a*b*b*sin(gamma)*sin(gamma); + const double S12 = a*b*c*c*(cos(alpha)*cos(beta) - cos(gamma)); + const double S23 = a*a*b*c*(cos(beta)*cos(gamma) - cos(alpha)); + const double S13 = a*b*b*c*(cos(gamma)*cos(alpha) - cos(beta)); + + const double brackets = S11*h*h + S22*k*k + S33*l*l + + 2*S12*h*k + 2*S23*k*l + 2*S13*h*l; + const double oneoverdsq = brackets / Vsq; + const double oneoverd = sqrt(oneoverdsq); + + return oneoverd / 2; +} |