diff options
| author | Thomas White <taw@physics.org> | 2019-05-23 16:42:27 +0200 |
|---|---|---|
| committer | Thomas White <taw@physics.org> | 2019-05-29 10:42:14 +0200 |
| commit | 581f8e8ab1b1d2833fd689540a2758bea1fc93ee (patch) | |
| tree | f2d0f329ebced450a7451287f3be138ac0aabab5 /src/diffraction.c | |
| parent | 1380592a04cba4621341a11cfb9a5526ea9dc4bf (diff) | |
Normalise sampled spectrum weights to total 1
Diffstat (limited to 'src/diffraction.c')
| -rw-r--r-- | src/diffraction.c | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/src/diffraction.c b/src/diffraction.c index bcbc62e8..6f52df11 100644 --- a/src/diffraction.c +++ b/src/diffraction.c @@ -457,6 +457,7 @@ void get_diffraction(struct image *image, int na, int nb, int nc, double *lut_c; int i; double kmin, kmax, step; + double norm = 0.0; cell_get_cartesian(cell, &ax, &ay, &az, &bx, &by, &bz, &cx, &cy, &cz); @@ -466,14 +467,20 @@ void get_diffraction(struct image *image, int na, int nb, int nc, spectrum_get_range(image->spectrum, &kmin, &kmax); step = (kmax-kmin)/(n_samples+1); - STATUS("%i samples\n", n_samples); + + /* Determine normalisation factor such that weights add up to 1 after + * sampling (bins must have constant width) */ + for ( i=1; i<=n_samples; i++ ) { + double k = kmin + i*step; + norm += spectrum_get_density_at_k(image->spectrum, k); + } for ( i=1; i<=n_samples; i++ ) { double k = kmin + i*step; double prob; /* Probability = p.d.f. times step width */ - prob = step * spectrum_get_density_at_k(image->spectrum, k); + prob = spectrum_get_density_at_k(image->spectrum, k)/norm; STATUS("Wavelength: %e m, weight = %.5f\n", 1.0/k, prob); |