Accessing potentials for adjustments

 

The following results are available under the following scenario: suppose that base has been adjusted initially by base and then partially by . We will use the notation

to mean the collection with excluded. Suppose that we might observe and (otherwise, data-related results are not available). For the following results we need to have issued the ADJUST:  command with either the noinfluence  control switched off, or with the influence  option switched on. For example, we might have issued the commands

BD>control  -noinfluence 

BD>adjust  [+/F1+F2]

where and are the names of bases. Typically, the results we are about to describe are used to label the arcs of influence diagrams. These labels can require some time and effort to calculate, and so we don't normally bother - we can switch off the noinfluence  control to force their calculation if we need them. Under these conditions, the following results are available.

Source arc influence

 

Usage

• arcin  operator; one argument in parenthesis. is the name of an element or base.

Under the conditions described above, returns

the partial resolution in the base B resulting from adding as well as D to the adjustment. This value remains until overwritten, so using this quantity if the above conditions are not satisfied can give unpredictable results. The arcin  operator thus is a measures of the worth of the base as a solitary carrier of information. The corresponding operator arcind  gives the corresponding size ratio as a diagnostic for this quantity when data is available.  

Source arc influence diagnostic

 

Usage

• arcind  operator; one argument in parenthesis. is the name of an element or base.

Under the conditions described above, and when data is available, returns

This is the observed size of the partial adjustment, divided by its expected size, being the trace of the corresponding partial resolution matrix, resulting from adding as well as D to the adjustment of B. This value remains until overwritten, so using this quantity if the above conditions are not satisfied can give unpredictable results. The corresponding operator arcin  gives the partial resolution used in the divisor.  

Destination arc influence

 

Usage

• arcout  operator; one argument in parenthesis. is the name of an element or base.

Under the conditions described above, returns

the partial loss in resolution due to withdrawing from the overall adjustment. This value remains until overwritten, so using this quantity if the above conditions are not satisfied can give unpredictable results. The arcout  operator thus is a measures of the worth of the base in supplying information about B that no other source gives. The corresponding operator arcoutd  gives a diagnostic for this quantity when data is available.  

Destination arc influence diagnostic

 

Usage

• arcoutd  operator; one argument in parenthesis. is the name of an element or base.

Under the conditions described above, and when data is available, returns

the observed size of the partial loss, divided by its expected size, being the trace of the corresponding partial resolution matrix, due to withdrawing from the adjustment. This value remains until overwritten, so using this quantity if the above conditions are not satisfied can give unpredictable results. The corresponding operator arcout  gives the partial loss in resolution used in the divisor.  

Arc path correlation

 

Usage

• arcpc  operator; one argument in parenthesis. is the name of an element or base.

Under the conditions described above, and when data is available, returns , the path correlation between the bearing for the node and the aggregated bearing for the remaining nodes being used for the adjustment. Zero is returned if the path correlation is undefined. See [31, section 5.5,]. This measures the observed degree of concordance between the information sources and . The value remains until overwritten, so using this quantity if the above conditions are not satisfied can give unpredictable results.