geometry.h File Reference

Data Structures
struct	polarisation

Enumerations
enum	PartialityModel {   PMODEL_UNITY ,   PMODEL_XSPHERE ,   PMODEL_OFFSET ,   PMODEL_RANDOM ,   PMODEL_GGPM }

Functions
RefList *	predict_to_res (Crystal *cryst, struct image *image, double max_res)
void	calculate_partialities (RefList *list, Crystal *cryst, struct image *image, PartialityModel pmodel)
void	update_predictions (RefList *list, Crystal *cryst, struct image *image)
struct polarisation	parse_polarisation (const char *text)
void	polarisation_correction (RefList *list, UnitCell *cell, struct polarisation p)
double	sphere_fraction (double rlow, double rhigh, double pr)
double	gaussian_fraction (double rlow, double rhigh, double pr)

Detailed Description

Geometry of diffraction

This contains the prediction and partiality calculation functions.

Enumeration Type Documentation

PartialityModel

enum PartialityModel

A PartialityModel describes a geometrical model which can be used to calculate spot partialities and Lorentz correction factors.

Enumerator
PMODEL_UNITY	Set all partialities and Lorentz factors to 1.
PMODEL_XSPHERE	Flat sphere model with super-Gaussian spectrum
PMODEL_OFFSET	Ewald offset model for monochromatic beam
PMODEL_RANDOM	Randomly assigned partialities
PMODEL_GGPM	Generalised gaussian prediction model

Function Documentation

calculate_partialities()

void calculate_partialities ( RefList * list, Crystal * cryst, struct image * image, PartialityModel pmodel )

extern

Parameters

list	A RefList
cryst	A Crystal
image	An image structure
pmodel	A PartialityModel

Calculates the partialities for the reflections in list, given the current state of cryst and image.

If pmodel is PMODEL_RANDOM or PMODEL_UNITY, then cryst can be NULL. If pmodel is PMODEL_UNITY, then image can also be NULL.

You must not have changed the crystal or image parameters since you last called predict_to_res or update_predictions, because this function relies on the limiting wavelength values calculated by those functions.

predict_to_res()

RefList * predict_to_res ( Crystal * cryst, struct image * image, double max_res )

extern

Parameters

cryst	A Crystal
image	An image structure
max_res	Maximum resolution to predict to (m^-1)

Calculates reflection positions for crys, as seen in image, up to maximum 1/d value max_res

Returns

A list of predicted reflections

update_predictions()

void update_predictions ( RefList * list, Crystal * cryst, struct image * image )

extern

Parameters

list	A RefList
cryst	A Crystal
image	An image structure

Updates the predicted reflections (positions and excitation errors, but not the actual partialities) in list, to match the current statea of crys as seen in image.

If you need to update the partialities as well, call calculate_partialities afterwards.