# frac_to_orth: From fractional to orthogonal coordinates In cry: Statistics for Structural Crystallography

## Description

This function transforms any number of fractional coordinates (x_f,y_f,z_f), arranged as a vector or in a matrix or data frame, into the corresponding number of orthogonal coordinates (x,y,z), arranged in the same format.

1. ochoice = 1: X axis along a; Y axis normal to a, in the (a,b) plane; Z axis normal to X and Y (and therefore parallel to c*).

2. ochoice = 2: this is also called "Cambridge setting". The X axis is along a*; the Y axis lies in the (a*,b*) plane; the Z axis is, consequently, along c.

## Usage

 1 frac_to_orth(xyzf, a, b, c, aa, bb, cc, ochoice = 1) 

## Arguments

 xyzf A vector or n\times 3 matrix or data frame of fractional crystal coordinates. a A real number. One of the unit cell's side lengths, in angstroms. b A real number. One of the unit cell's side lengths, in angstroms. c A real number. One of the unit cell's side lengths, in angstroms. aa A real number. One of the unit cell's angles, in degrees. bb A real number. One of the unit cell's angles, in degrees. cc A real number. One of the unit cell's angles, in degrees. ochoice A natural integer indicating the choice of orthogonal transformation. 1 corresponds to the first choice and 2 to the second choice in Giacovazzo's book (see xtal_mat01 and xtal_mat02).

## Value

A n\times 3 matrix or data frame of orthogonal coordinates corresponding to the fractional coordinates provided in the input.

## Examples

 1 2 3 4 5 # Matrix containing 3 fractional coordinates xyzf <- matrix(c(0.1,0.2,0.3,0.2,0.6,0.7,0.15,0.28,0.55),ncol=3,byrow=TRUE) # Cartesian coordinates xyz <- frac_to_orth(xyzf,10,30,20,90,90,90,1) 

cry documentation built on May 3, 2021, 9:06 a.m.