$Warnings ON {/All or /Last}
Warnings can occur during calculations for a variety of reasons. For example, a warning may be generated by a property correlation if is used beyond its range of applicability. A warning may be generated if the equations that have been solved appear to be singular. A user-generated warning message can be displayed with the WARNING procedure.
Warning messages will not be generated unless they are enabled. A default setting for enabling warning messages is provided as an option in the Preferences dialog. However, this default setting is overridden by the $Warnings ON/OFF directives, which can be placed anywhere in the Equations window. $Warnings ON indicates that if a warning message is issued, it will be appear in the Warnings Information dialog. $Warnings OFF will cancel the display of any warning messages that occur in following calculations. It is possible to specifically select which equations can or can not issue warning messages by surrounding the equations with $Warning ON/OFF directives. In some situations, it is necessary to ensure that the warnings are set as you expect, particularly for Distributable programs. In this case, it is convenient to use the $Warning On/OFF directive, which overrides the setting in the Preferences dialog.
EES usually has to iteratively solve the equations in the Equations window to arrive at the correct solution. Warnings may occur during the iteration process and then not occur during the final iteration. This situation often results from one or more poor guess values for variables and it can be fixed by updating guess values after a successful solution. If /ALL appears in the $Warning directive, then all of the warnings, including those from previous iterations will be displayed. Alternatively, if /LAST appears in the directive, only the warnings from the last iteration will be displayed.
If warnings messages have been issued, EES will normally display the Warning Information dialog directly after calculations are completed. However, automatic display of this dialog can be controlled by the Warnings setting in the status bar of the Equations window. If the Warning setting in the status bar is set to off, the Warning Information dialog will not be automatically displayed. However, it is still can be viewed by selecting Warnings from the Windows menu.