CVAR
CVAR, IR
, IA
, IB
, ITYPE
, DATUM
, Name
Computes covariance between two quantities.
IR
Arbitrary reference number assigned to the resulting variable (2 to
NV
(NUMVAR)). If this number is the same as for a previous variable, the previous variable will be overwritten with this result.IA
,IB
Reference numbers of the two variables to be operated on. If only one, leave
IB
blank.ITYPE
Defines the type of response PSD to be calculated:
0,1
—
Displacement (default).
2
—
Velocity.
3
—
Acceleration.
DATUM
Defines the reference with respect to which covariance is to be calculated:
1
—
Absolute value.
2
—
Relative to base (default).
Name
Thirty-two character name for identifying the variable on listings and displays. Embedded blanks are compressed upon output.
Notes
This command computes the covariance value for the variables referenced by the reference
numbers IA
and IB
. If
DATUM
= 2, the variable referenced by IR
will contain the individual modal contributions (that is, the dynamic or relative values). If
DATUM
= 1, the variable referenced by IR
will contain the modal contributions followed by the contributions of pseudo-static and
covariance between dynamic and pseudo-static responses. File.psd must be
available for the calculations to occur.