carries out an operation using amplitudes of
xrefin properties.
COMPlex
carries out an operation in complex space.
PHASe
carries out an operation using phases of
xrefin properties. Phases are
manipulated in degrees.
SCALe
involves an operation that multiplies the left-hand side
(lhs) by
a scale factor , which is defined as
(13.12)
where rhs represents the right-hand side of the equation.
The action of this statement is identical to the
scaling carried out when computing the value or the residual
(cf. Eqs. 13.1, 13.6), except that it refers
the scaling to the right-hand side of the equation, whereas
in the residual or value evaluation the scaling
refers to
.
Therefore, if the right-hand side of the scaling operation consists
of , the program refers only to but not to
to
.
xrefin-do-expression:==
xrefin-vflc
[ op xrefin-do-expression ]
represents a mathematical operation and
is defined in Section 2.16.
xrefin-vflc:==
function
xrefin-function
symbol real integer
complex xrefin-property
represents mathematical functions
and is defined in Section 2.16. Special
xrefin functions are defined below. The data
type of the function arguments has to match
the data type of the operands.
xrefin-property:==
FCALC
specifies calculated structure factors (complex).
FOBS
specifies observed structure factors (complex).
FPART
specifies partial structure factors (complex).
SIGMA
specifies values (real).
TEST
is an array for cross-validation that
allows one to compute the free value (see Chapter
17).
WEIGHT
specifies weights (real).
xrefin-function:==
H()
defines an array that consists of the Miller index h.
K()
defines an array that consists of the Miller index k.
L()
defines an array that consists of the Miller index l.
S()
defines an array that consists of the length of
the reciprocal lattice vector for each reflection h,k,l.