I would like to use optimize parameters with the “Parameter Optimization Loop nodes” for a rando forest model.
Parameters to be optimized:
Number of Trees (numTrees):
Start vakue: 200
Stop value: 350
Step size: 50
Tree Depth (maxDepth):
Start value : 10
Stop value: 18
Step size: 4
Minimum Node Size (minNodeSize):
Start value: 10
Stop value: 30
Step size: 10
Minimum Child Size (minChildSize):
Start value: 5
Stop value: 15
Step size: 5
Unfortunately, I always get the same error message: “Invalid minimum child size (10); must be at most 2 x minimum node size (10)”. I have tried countless other combination. The error remains.
Minimum split node size is the minimum number of records in a decision tree node so that another split is attempted. If enabled, this number needs to be at least twice as large as the minimum child node size (as otherwise for binary splits one of the two children would have less records than specified).
Minimum child node size is the minimum number of records in child nodes. It can be at most half of the minimum split node size (see above).
Your parameters result in a situation where the minimum child node size can equal more than 1/2 of the minimum node split size. Or said the other way around, the minimum node split size can be less than 2x the minimum child node size.
This is not allowed.
For example, if you’re using a brute force search, then iteration 36 will be the first to fail :
Iteration
minChildSize
minNodeSize
maxDeph
numTrees
0.5 x minNodeSize
is minChildSize acceptable?
0
5
10
10
200
5
Pass
1
5
10
10
250
5
Pass
2
5
10
10
300
5
Pass
3
5
10
10
350
5
Pass
4
5
10
14
200
5
Pass
5
5
10
14
250
5
Pass
6
5
10
14
300
5
Pass
7
5
10
14
350
5
Pass
8
5
10
18
200
5
Pass
9
5
10
18
250
5
Pass
10
5
10
18
300
5
Pass
11
5
10
18
350
5
Pass
12
5
20
10
200
10
Pass
13
5
20
10
250
10
Pass
14
5
20
10
300
10
Pass
15
5
20
10
350
10
Pass
16
5
20
14
200
10
Pass
17
5
20
14
250
10
Pass
18
5
20
14
300
10
Pass
19
5
20
14
350
10
Pass
20
5
20
18
200
10
Pass
21
5
20
18
250
10
Pass
22
5
20
18
300
10
Pass
23
5
20
18
350
10
Pass
24
5
30
10
200
15
Pass
25
5
30
10
250
15
Pass
26
5
30
10
300
15
Pass
27
5
30
10
350
15
Pass
28
5
30
14
200
15
Pass
29
5
30
14
250
15
Pass
30
5
30
14
300
15
Pass
31
5
30
14
350
15
Pass
32
5
30
18
200
15
Pass
33
5
30
18
250
15
Pass
34
5
30
18
300
15
Pass
35
5
30
18
350
15
Pass
36
10
10
10
200
5
Fail
37
10
10
10
250
5
Fail
38
10
10
10
300
5
Fail
39
10
10
10
350
5
Fail
40
10
10
14
200
5
Fail
41
10
10
14
250
5
Fail
42
10
10
14
300
5
Fail
43
10
10
14
350
5
Fail
44
10
10
18
200
5
Fail
45
10
10
18
250
5
Fail
46
10
10
18
300
5
Fail
47
10
10
18
350
5
Fail
48
10
20
10
200
10
Pass
49
10
20
10
250
10
Pass
50
10
20
10
300
10
Pass
51
10
20
10
350
10
Pass
52
10
20
14
200
10
Pass
53
10
20
14
250
10
Pass
54
10
20
14
300
10
Pass
55
10
20
14
350
10
Pass
56
10
20
18
200
10
Pass
57
10
20
18
250
10
Pass
58
10
20
18
300
10
Pass
59
10
20
18
350
10
Pass
60
10
30
10
200
15
Pass
61
10
30
10
250
15
Pass
62
10
30
10
300
15
Pass
63
10
30
10
350
15
Pass
64
10
30
14
200
15
Pass
65
10
30
14
250
15
Pass
66
10
30
14
300
15
Pass
67
10
30
14
350
15
Pass
68
10
30
18
200
15
Pass
69
10
30
18
250
15
Pass
70
10
30
18
300
15
Pass
71
10
30
18
350
15
Pass
72
15
10
10
200
5
Fail
73
15
10
10
250
5
Fail
74
15
10
10
300
5
Fail
75
15
10
10
350
5
Fail
76
15
10
14
200
5
Fail
77
15
10
14
250
5
Fail
78
15
10
14
300
5
Fail
79
15
10
14
350
5
Fail
80
15
10
18
200
5
Fail
81
15
10
18
250
5
Fail
82
15
10
18
300
5
Fail
83
15
10
18
350
5
Fail
84
15
20
10
200
10
Fail
85
15
20
10
250
10
Fail
86
15
20
10
300
10
Fail
87
15
20
10
350
10
Fail
88
15
20
14
200
10
Fail
89
15
20
14
250
10
Fail
90
15
20
14
300
10
Fail
91
15
20
14
350
10
Fail
92
15
20
18
200
10
Fail
93
15
20
18
250
10
Fail
94
15
20
18
300
10
Fail
95
15
20
18
350
10
Fail
96
15
30
10
200
15
Pass
97
15
30
10
250
15
Pass
98
15
30
10
300
15
Pass
99
15
30
10
350
15
Pass
100
15
30
14
200
15
Pass
101
15
30
14
250
15
Pass
102
15
30
14
300
15
Pass
103
15
30
14
350
15
Pass
104
15
30
18
200
15
Pass
105
15
30
18
250
15
Pass
106
15
30
18
300
15
Pass
107
15
30
18
350
15
Pass
My advice is to specify either the Minimum node split size or the Minimum child node size, not both.