[26] | 1 | .EN |
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| 2 | .TH C4.5 1 |
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| 3 | .SH NAME |
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| 4 | .PP |
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| 5 | consult \- classify items using a decision tree |
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| 6 | .SH SYNOPSIS |
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| 7 | .PP |
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| 8 | .B consult |
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| 9 | [ \fB-f\fR FNS ] |
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| 10 | [ \fB-t\fR ] |
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| 11 | .SH DESCRIPTION |
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| 12 | .PP |
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| 13 | .I Consult |
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| 14 | reads a decision tree produced by c4.5 and |
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| 15 | uses this to classify items whose description |
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| 16 | is provided by the user. |
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| 17 | The decision tree read is |
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| 18 | .I filestem.tree, |
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| 19 | where |
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| 20 | .I filestem |
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| 21 | is the file name stem (see manual entry for c4.5). |
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| 22 | .PP |
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| 23 | .I Consult |
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| 24 | prompts for the value of an attribute when needed. |
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| 25 | Unknown attribute values are specified as '?'. |
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| 26 | .PP |
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| 27 | If the attribute has discrete values, its value |
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| 28 | can be specified either as |
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| 29 | .ti 8 |
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| 30 | .I v |
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| 31 | .br |
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| 32 | where v is one of the permissible values of the attribute, or as |
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| 33 | .ti 8 |
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| 34 | .I "v1:p1, v2:p2, ... , vn:pn" |
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| 35 | .br |
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| 36 | where the vi's are some or all of the permissible values of the |
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| 37 | attribute and the pi's are corresponding probabilities. |
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| 38 | If the sum of the pi's is less than 1, the remaining probability |
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| 39 | is distributed equally among the unspecified values of the |
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| 40 | attribute. For example, if attribute A has possible values |
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| 41 | X, Y and Z, the reply |
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| 42 | .ti 8 |
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| 43 | X:0.5 |
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| 44 | .br |
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| 45 | is the same as |
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| 46 | .ti 8 |
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| 47 | X:0.5, Y:0.25, Z:0.25 |
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| 48 | .PP |
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| 49 | If the attribute has real values, its value can be |
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| 50 | specified either as |
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| 51 | .ti 8 |
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| 52 | .I r |
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| 53 | .br |
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| 54 | where r is a real number, or as |
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| 55 | .ti 8 |
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| 56 | .I r1 - r2 |
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| 57 | .br |
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| 58 | where r1 and r2 are real numbers. The latter form is |
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| 59 | taken to mean "somewhere in the interval [r1,r2]". |
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| 60 | .PP |
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| 61 | To display the subtree of the decision tree with the |
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| 62 | current node at the root, '?t' may be entered in |
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| 63 | response to a request for an attribute value. |
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| 64 | .PP |
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| 65 | When all relevant attributes have been determined, |
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| 66 | consult will give one or more classes that the item |
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| 67 | might belong to. The likelihood of a class may be |
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| 68 | indicated by a probability, followed sometimes by a |
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| 69 | probability interval. For example, |
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| 70 | .ti 8 |
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| 71 | .I "C1 CF = 0.9 [0.85 - 1]" |
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| 72 | .br |
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| 73 | means "class C1 with probability in the interval 0.85 - 1, |
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| 74 | and with best guess probability 0.9". |
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| 75 | .PP |
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| 76 | At the end of each item, consult will prompt for |
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| 77 | retrial of the same item, a new item, or end of session. |
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| 78 | When retrying an item, the previous values of queried |
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| 79 | attributes are displayed in square brackets. If the |
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| 80 | value is unchanged, reply with a carriage return; |
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| 81 | otherwise, specify the changed value. |
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| 82 | .PP |
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| 83 | Options and their meanings are: |
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| 84 | .PP |
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| 85 | .TP 12 |
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| 86 | .BI \-f filestem\^ |
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| 87 | Specify the filename stem (default |
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| 88 | .B DF) |
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| 89 | .TP |
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| 90 | .B \-t |
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| 91 | Display the decision tree at the start of the consulting |
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| 92 | session. |
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| 93 | .SH FILES |
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| 94 | .PP |
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| 95 | .in 8 |
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| 96 | consult |
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| 97 | .br |
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| 98 | filestem.names |
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| 99 | .br |
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| 100 | filestem.tree |
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| 101 | .in 0 |
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| 102 | .PP |
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| 103 | .SH SEE ALSO |
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| 104 | .PP |
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| 105 | c4.5(1) |
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| 106 | .PP |
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| 107 | .SH BUGS |
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