CVAR

CVAR

CVAR, IR, IA, IB, ITYPE, DATUM, Name
Computes covariance between two quantities.

POST26: Special Purpose

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 (i.e., 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.

Menu Paths

Main Menu>TimeHist Postpro>Calc Covariance