Options

Rfactor recognizes four options. These options can be set with the OPTION statement described in the ``Standard TNT Data Statements'' section of the ``Shared I/O Properties" chapter. The first two options simply affect how the agreement statistics are printed in the log file. The SIGMA option makes a substantive change to the refinement method. As an example, the activation of the SIGMA option would require the statement

OPTION SET SIGMA

• FOM

  This option causes the Rfactor command ``REPORT RFACTOR'' to print additional statistics describing the agreement between the two data sets. These statistics are weighted by the figure of merit and show the means and RMS's when those reflections which are well phased are given greater weight.

• INTENSITY

  This option causes the Rfactor command ``REPORT RFACTOR'' to list the statistics in intensity shells instead of the usual resolution shells.

• SIGMA

  This option causes Rfactor to weight each reflection by when calculating the function value, curvature, and Fourier coefficients. The SIGMA option is preferred if the sigmas in the FO file are reliable. When this option is set additional statistics are printed in the log file. Sigma weighting is used when calculating scale factors, anisotropic temperature factors, Sim weighting coefficients, the RFACTOR function value and curvature, the ROTATION function value and curvature, and difference coefficients.

• VERBOSE

  The Verbose option causes the program to write additional information to the log file about the choices it makes.