Trace: • r

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# r

**[ randomi**

*z*

*e_file_out_normal***$file]**

Randomizes the calculated pattern Y_{c} using a Normal distribution and writes Y_{c} to the file $file.

**[ rand_xyz !E]**

If *continue_after_convergence* is defined then *rand_xyz* is executed at the end of a refinement cycle. It adds to the site fractional coordinate a vector **u**,the direction of which is random and the magnitude in Å is:

|**u**| = T *rand_xyz*

where T is the current *temperature*. Thus to add a shift to an atom between 0 and 1 Å the following could be used:

temperature 1

site . . . occ 1 C beq 1 rand_xyz = Rand(0,1);

Note that only fractional coordinates (*x*, *y*, *z*) that are independent parameters are randomized.

**[ r_bragg #]**

Reports on the R-Bragg value. R-Bragg is independent of hkl's and thus can be calculated for all phase types that contain phase peaks.

**[ rebin_with_dx_of !E]**

*rebin_with_dx*_of rebins the observed data, see example CLAY.INP. It can be a function of the reserved parameter X as demonstrated in tof_bank2_1.inp. If *rebin_with_dx*_of evaluates to a constant then the observed data is re-binned to equal x-axis steps. For observed data that is of unequal x-axis steps then re-binning provides a means of converting to equal x-axis steps.

**[ rigid]…**

**[ point_for_site $site [ux|ua E] [uy|ub E] [uz|uc E] ]…**

**[ in_cartesian] [in_FC]**

**[ z_matrix $atom_1 [$atom_2 E] [$atom_3 E] [$atom_4 E] ] …**

**[ rotate E [qx|qa E] [qy|qb E] [qz|qc E] ]…**

**[ operate_on_points $sites]**

**[ in_cartesian] [in_FC]**

**[ translate [tx|ta E] [ty|tb E] [tz|tc E] ]…**

**[ operate_on_points $sites]**

**[ rand_xyz #displacement]**

**[ in_cartesian] [in_FC]**

**[ start_values_from_site $unique_site_name]**

*rigid* defines a rigid body and associated translation and rotation operations. These operations are capable of creating and manipulating rigid bodies with hinges (torsion angles).

*point_for_site* defines a point in space with Cartesian coordinates given by the parameters *ux, uy uz*. Fractional equivalents can be defined using *ua*, *ub* and *uc*. $site is the *site* that the *point_for_site* represents.

*z_matrix* defines a point in space with coordinates given in Z-matrix format as follows::

- E can be an equation, constant or a parameter name with a value.
- $atom_1 specifies the site that the new Z-matrix point represents.
- The E after $atom_2 specifies the distance in Å between $atom_2 and $atom_1. $atom_2 must exist if $atom_1 is preceded by at least one point.
- The E $atom_3 specifies the angle in degrees between $atom_3-$atom_2- $atom_1. $atom_3 must exist if $atom_1 is preceded by at least two points.
- The E $atom_4 specifies the dihedral angle in degrees between the plane formed by $atom_3-$atom_2-$atom_1 and the plane formed by $atom_4-$atom_3-$atom_2. This angle is drawn using the right hand rule with the thumb pointing in the direction $atom_3 to $atom_2. $atom_4 must exist if $atom_1 is preceded by at least three sites of the rigid body.
- If $atom_1 is the first point of the rigid body then it is placed at Cartesian (0, 0, 0). If $atom_1 is the second point of the rigid body then it is placed on the positive z-axis at Cartesian (0, 0, E) where E corresponds to the E in [$atom_2 E]. If $atom_1 is the third point of the rigid body then it is placed in the x-y plane.

*rotate* rotates *point_for_site*’s an amount as defined by the *rotate* E equation around the vector defined by the Cartesian vector *qx*, *qy*, *qz*. The vector can be defined in fractional coordinates using *qa*, *qb* and *qc* instead.

*translate* performs a translation of *point_for_site*’s an amount in Cartesian equal to *tx*, *ty*, *tz*. The amount can be defined in fractional coordinates using *ta*, *tb* and *tc* instead.

If *in_cartesian* or *in_FC* is defined then the coordinates are interpreted as Cartesian or fractional atomic coordinates, respectively.

*rotate* and *translate* operates on any previously defined *point_for_site*’s; alternatively, *point_for_site*’s operated on can be identified using the *operate_on_points* keyword*.* The *operate_on_points* keyword must refer to previously defined *point_for_site*’s (see section 7.6 for a description of how to identify sites).

When *continue_after_convergence* is defined, *rand_xyz* processes are initiated after convergence. It introduces a random displacement to the translate fractional coordinates (*tx*, *ty*, *tz*) that are independent parameters. The size of the random displacement is given by the current *temperature* multiplied by #displacement where #displacement is in Å.

*start_values_from_site* initializes the values *ta*, *tb*, *tc* with corresponding values taken from the site $unique_site_name.

See section 7.10 for a description of rigid bodies.

**[ Rp #] [Rs #]**

Defines the primary and secondary radius of the diffractometer in mm. The default is 217.5 mm.

**[ r_p #] [r_p_dash #] [r_wp #] [r_wp_dash #] [r_exp #] [r_exp_dash #] [gof #]**

**[ weighted_Durbin_Watson #]**

*xdd* dependent or global refinement indicators. Keywords ending in “_dash” correspond to background subtracted values, see section 5.6.