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Partial adjustments - withdrawing bases

 


tex2html_wrap_inline33790 tex2html_wrap_inline33790 Syntax

BD>adjust : [- / D tex2html_wrap_inline33794 + D tex2html_wrap_inline33798 + ...+ D tex2html_wrap_inline36896 ] tex2html_wrap_inline33712

where tex2html_wrap_inline36864 are the names of bases or elements.

tex2html_wrap_inline33806 tex2html_wrap_inline33806

In addition to adding quantities to a fit, we can withdraw them. This form of the command assumes that there is a current adjustment: suppose that it is tex2html_wrap_inline36988 where B is the collection being adjusted; tex2html_wrap_inline36990 are collections which have been fitted explicitly, and F comprises the remaining collections fitted. The effect of the command is now to carry out the adjustment tex2html_wrap_inline36992 (dropping tex2html_wrap_inline36880 ), which becomes the new current adjustment. The difference between this and the previous adjustment is a partial adjustment which quantifies the effect of losing tex2html_wrap_inline36880 as an information source. This process continues, dropping a tex2html_wrap_inline36882 at each stage until the final current adjustment is tex2html_wrap_inline36916 .

The base notation discussed in §9.1.2 may be used. Any base which is presented for use during an adjustment must contain only elements having beliefs, and no data elements. Note that influence diagrams are not drawn when withdrawing quantities from an adjustment.

We emphasize that bases being withdrawn must have been explicitly added. That is, the following sequence of commands is not useful:

BD>adjust : [B/D1+D2] tex2html_wrap_inline33712

BD>adjust : [-/D3] tex2html_wrap_inline33712

as the base D3 would not have been explicitly fitted during the current adjustment, and so cannot be removed.



David Wooff
Wed Oct 21 15:14:31 BST 1998