**Uncert.ParDif and Uncert.Percent**

When the Uncertainty Propagation or Uncertainty Propagation Table has completed its calculations, the uncertainties of the calculated variable(s) are displayed in the Solution window. Also displayed are the partial derivatives of the calculated variables with respect to each of the measured variables and the % of the uncertainty that can be attributed to each of the measured variables. These uncertainty calculation results can be made available to EES variables with the Uncert.ParDif and Uncert.Percent functions.

Uncert.ParDif(X,Y) returns the partial derivative of variable X with respect to variable Y.

Uncert.Percent(X,Y) returns the percent of the total uncertainty in variable X that can be attributed to variable Y.

These functions are only applicable when the Uncertainty Propagation or Uncertainty Propagation Table commands are used. In this case, variable X must be one of the selected calculated variables and Y must be one of the selected measured variables in the uncertainty analysis.

An error will be displayed if these commands are used in non-uncertainty calculations. In order to avoid errors, it may be best to enclose the Uncert.ParDif and Uncert.Percent commands within the $IF Uncertainty (or $IF UncertaintyTable) $ENDIF directives, as indicated below.

$IF UNCERTAINTY

PD=Uncert.ParDif(X,Y)

PC=Uncert.Percent(X,Y)

$ENDIF