diff options
| -rw-r--r-- | src/relrod.c | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/src/relrod.c b/src/relrod.c index 9595e110..bbb5fb68 100644 --- a/src/relrod.c +++ b/src/relrod.c @@ -66,6 +66,7 @@ void get_reflections(struct image *image, UnitCell *cell) double bsx, bsy, bsz; /* "b*" lattice parameter */ double csx, csy, csz; /* "c*" lattice parameter */ signed int h, k, l; + double res_max; /* Get the reciprocal unit cell */ cell_get_reciprocal(cell, &asx, &asy, &asz, @@ -78,6 +79,22 @@ void get_reflections(struct image *image, UnitCell *cell) omega = image->omega; wavenumber = 1.0/image->lambda; + /* Calculate (roughly) the maximum resolution */ + if ( image->fmode == FORMULATION_CLEN ) { + double w2, h2; + w2 = image->width/2; h2 = image->height/2; + w2 = pow(w2, 2.0); h2 = pow(h2, 2.0); + res_max = sqrt(w2 + h2) / image->resolution; + res_max *= (wavenumber / image->camera_len); + } else { + fprintf(stderr, + "Unrecognised formulation mode in get_reflections" + " (resolution cutoff calculation)\n"); + return; + } + printf("Resolution cutoff is %5.2f nm^-1\n", res_max/1e9); + res_max = pow(res_max, 2.0); + /* Calculate the (normalised) incident electron wavevector */ mapping_rotate(0.0, 0.0, 1.0, &nx, &ny, &nz, omega, tilt); kx = nx / image->lambda; @@ -106,6 +123,9 @@ void get_reflections(struct image *image, UnitCell *cell) g_sq = modulus_squared(xl, yl, zl); gn = xl*nx + yl*ny + zl*nz; + /* Early bailout if resolution is clearly too high */ + if ( g_sq > res_max ) continue; + /* Next, solve the relrod equation to calculate * the excitation error */ a = 1.0; |