consult.1

c4.5的源码决策树最全面最经典的版本

.EN
.TH C4.5 1
.SH NAME
.PP
consult \- classify items using a decision tree
.SH SYNOPSIS
.PP
.B consult
[ \fB-f\fR FNS ]
[ \fB-t\fR ]
.SH DESCRIPTION
.PP
.I Consult
reads a decision tree produced by c4.5 and
uses this to classify items whose description
is provided by the user.
The decision tree read is
.I filestem.tree,
where
.I filestem
is the file name stem (see manual entry for c4.5).
.PP
.I Consult
prompts for the value of an attribute when needed.
Unknown attribute values are specified as '?'.
.PP
If the attribute has discrete values, its value
can be specified either as
.ti 8
.I v
.br
where v is one of the permissible values of the attribute, or as
.ti 8
.I "v1:p1, v2:p2, ... , vn:pn"
.br
where the vi's are some or all of the permissible values of the
attribute and the pi's are corresponding probabilities.
If the sum of the pi's is less than 1, the remaining probability
is distributed equally among the unspecified values of the
attribute.  For example, if attribute A has possible values
X, Y and Z, the reply
.ti 8
X:0.5
.br
is the same as
.ti 8
X:0.5, Y:0.25, Z:0.25
.PP
If the attribute has real values, its value can be
specified either as
.ti 8
.I r
.br
where r is a real number, or as
.ti 8
.I r1 - r2
.br
where r1 and r2 are real numbers.  The latter form is
taken to mean "somewhere in the interval [r1,r2]".
.PP
To display the subtree of the decision tree with the
current node at the root, '?t' may be entered in
response to a request for an attribute value.
.PP
When all relevant attributes have been determined,
consult will give one or more classes that the item
might belong to.  The likelihood of a class may be
indicated by a probability, followed sometimes by a
probability interval.  For example,
.ti 8
.I "C1  CF = 0.9 [0.85 - 1]"
.br
means "class C1 with probability in the interval 0.85 - 1,
and with best guess probability 0.9".
.PP
At the end of each item, consult will prompt for
retrial of the same item, a new item, or end of session.
When retrying an item, the previous values of queried
attributes are displayed in square brackets.  If the
value is unchanged, reply with a carriage return;
otherwise, specify the changed value.
.PP
Options and their meanings are:
.PP
.TP 12
.BI \-f filestem\^
Specify the filename stem (default
.B DF)
.TP
.B \-t
Display the decision tree at the start of the consulting
session.
.SH FILES
.PP
.in 8
consult
.br
filestem.names
.br
filestem.tree
.in 0
.PP
.SH SEE ALSO
.PP
c4.5(1)
.PP
.SH BUGS