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, double max_res)
void	calculate_partialities (Crystal *cryst, PartialityModel pmodel)
void	update_predictions (Crystal *cryst)
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	(	Crystal *	cryst,
		PartialityModel	pmodel
	)

Parameters

cryst	A Crystal
pmodel	A PartialityModel

Calculates the partialities for the reflections in cryst, given the current crystal and image parameters. The crystal's image and reflection lists must be set. The specified PartialityModel will be used.

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,
		double	max_res
	)

Parameters

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

Calculates reflection positions for crys, up to maximum 1/d value max_res

Returns

A list of predicted reflections

update_predictions()

void update_predictions

(

Crystal *

cryst

)

Parameters

cryst

A Crystal

Updates the predicted reflections (positions and excitation errors, but not the actual partialities) of cryst's reflections according to the current state of the crystal (e.g. its unit cell parameters).

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