Nonlinear Regression

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1. General

For nonlinear regression, all statistical software packages available today, for example, SPSS, SAS, Statistical,Origin Pro, DataFit, Stata and Systat, need end-users to provide initial guess/start values, and the successful of regression computation is depended on those start values haveily. Unfortunately, for general users in most cases, the guess of the start values are nightmare. They have to try and try, and even so, the results are not guaranteed to be optimal ones since the drawbacks of local optimization algorithms adopted (the most used algorithms are Levenberg-Marquardt (LM), BFGS, Simplex)

   With our revolution algorithms of Global Levenberg-Marquardt (GLM) and Global BFGS, as well as many other global optimation algorithms, Auto2Fit is now no long to need end-users to guess/provide start values, but use freely random values.

2. NIST Test

    The nonlinear data set form NIST are widely used for the purpose of performance test. Almost all software developers in statistical/nonlinear areas claimed that they have passed the test data sets from NIST, but they have to use one of two start value sets provided already by NIST. Auto2Fit, however, use only free random values as initial guess, but with almost 100% successful, amazing? No any others may achieve so!!!. The test results are as followings:

Table.1  Results of Nonlinear Test Data Set from NIST

No.

Name of Test Set

Levels

No. of Parameters

Start Values

Algorithms

Rate of Success (%)

1

Misra1a

Low

2

Default random values between 0 to 5

LM + UGO

 

100

2

Chwirut2

3

100

3

Chwirut1

3

100

4

Lanczos3

6

100

5

Gauss1

8

> 90

6

Gauss2

8

> 90

7

DanWood

2

100

8

Misra1b

2

100

9

Kirby2

Average

5

100

10

Hahn1

7

100

11

Nelson

3

100

12

MGH17

5

100

13

Lanczos1

6

100

14

Lanczos2

6

100

15

Gauss3

8

> 90

16

Misra1c

2

100

17

Misra1d

2

100

18

Roszman1

4

100

19

ENSO

9

100

20

MGH09

High

4

100

21

Thurber

7

100

22

BoxBod

2

100

23

Rat42

3

100

24

MGH10

3

100

25

Eckerle4

3

100

26

Rat43

4

100

27

Bennett5

3

>90

*:SM:Simplex MethodMIO:Maximum Inheirt OPtimization

3. Challenge Test Data

    The test data sets from NIST are too simple for Auto2Fit. Here we provide below some more difficult test data. There is only one unique optimal solution of each data set. The results of RMSE and R-Square for each data set are given for reference.You may try any other softwares or tools.  If anyone can get correct answers using tools other than Auto2Fit, please write to here.

   Some of those test data are very hard, and may never get right answers without using Auto2Fit. Even for Auto2Fit, it does not ensure every run will be successful. The suggested algorithms for solving those problems in Auto2Fit are Global Levenberg-Marquard or Global BFGS. In some cases, you may try to change the control parameter of "Population Size" from default 30 to 50 or more

 

Test Data

Regression Equations

Variables

Parameters

RMSE

R^2

1

y=1/(p1+p2*X^p3)+p4*x^p5

x, y

p1 to p5

104.376667

0.99678004

2

y = (p1+p2*x1+p3*x2+p4*x3+p5*x4)/(1+a1*x1+a2*x2+a3*x3+a4*x4)

x1 to x4, y

p1 to p5, a1 to a4

0.3028129

0.9346422

3

y = p1/(1+p2/x+x/p3)

x, y

p1 to p3

0.8767278

0.969929562

4

y = (a0+a1*x1+a2*x2+a3*x3+a4*x4)/(1+b1*x1+b2*x2+b3*x3+b4*x4)

x1 to x4, y

a0 to a4, b1 to b4

48.05714

0.80514286

5

z = p1+p2*x^p3+p4*y^p5+p6*x^p7*y^p8

x, y, z

p1 to p8

0.2703296

0.994632848

6

y = a0+a1*x^k1+a2*x^k2+a3*x^k3

x, y

a0 to a3, k1 to k3

0.0214726136

0.999644261

7

z = (p1+p2*x+p3*y+p4*x*y)/(1+p5*x+p6*y+p7*x*y)

x, y, z

p1 to p7

1.00626078

0.9715471

8

y=p1/((p2+x1)*(1+p3*x2)*(x3-p4)^2)+p5*x3^p6

x, y

p1 to p6

0.01977698

0.995372

9

y=a*exp(b*abs(x+c)^d)

x, y

a, b, c, d

1.1546909

0.9704752

 

 

Test Data 1

No      x           y

No      x           y

No      x           y

No      x           y

No      x           y

No      x           y

1       160.73  6266.7

2       159.82  6151.9

3       158.84  6035.1

4       157.86  5920.9

5       156.87  5812.6

6       155.88  5702.2

7       154.89  5594.9

8       153.96  5491.3

9       152.97  5385

10      151.98  5282.2

11      150.99  5181.3

12      150.06  5084.8

13      149.08  4988.8

14      148.09  4892.2

15      147.1   4796.9

16      146.17  4701

17      145.18  4608

18      144.2   4515.2

19      143.2   4429.6

20      142.21  4342.9

21      141.25  4255.6

22      140.2   4167.1

23      139.14  4077.6

24      138.05  3987.9

25      136.96  3898.9

26      135.94  3808.5

27      134.84  3717.7

28      133.74  3628.9

29      132.65  3543

30      131.57  3456.3

31      130.55  3372.5

32      129.47  3292.8

33      128.4   3212.7

34      127.33  3133.6

35      126.34  3056.6

36      125.29  2985.5

37      124.26  2912.5

38      123.23  2842.9

39      122.21  2774.1

40      121.21  2708.3

41      120.27  2642.1

42      119.27  2580.2

43      118.29  2518.7

44      117.32  2459.1

45      116.42  2401.1

46      115.48  2344.3

47      114.55  2290.9

48      113.62  2237.5

49      112.7   2189

50      111.85  2138.8

51      110.94  2089.4

52      110.03  2042.4

53      109.13  1998.1

54      108.28  1953.6

55      107.38  1906.6

56      106.48  1867.8

57      105.6   1824.5

58      104.72  1784.3

59      103.91  1745

60      103.05  1704.5

61      102.2   1668.7

62      101.35  1629

63      100.51  1590.4

64      99.739  1552.5

65      98.913  1514.7

66      98.103  1476.4

67      97.308  1444.3

68      96.513  1411.4

69      95.78   1378.5

70      95.002  1344.8

71      94.239  1307.8

72      93.482  1276.1

73      92.776  1243.5

74      92.039  1212.9

75      91.314  1178.7

76      90.604  1148.4

77      89.942  1115.9

78      89.244  1084.5

79      88.559  1051.5

80      87.889  1029.7

81      87.226  996.16

82      86.569  965.86

83      85.963  937.72

84      85.323  907.87

85      84.694  877.58

86      84.081  838.17

87      83.473  819.48

88      82.876  797.76

89      82.287  768.54

90      81.811  749.96

91      81.178  724.39

92      80.614  697.24

93      80.118  674.67

94      79.574  649.49

95      79.011  629.83

96      78.478  614.6

97      78.012  591.87

98      77.494  573.43

99      76.927  558.94

100     76.512  539.45

101     75.962  526.99

102     75.472  514.14

103     75.014  504.11

104     74.566  484.4

105     74.123  473.23

106     73.608  468.93

107     73.183  453.77

108     72.774  448.58

109     72.369  447.73

110     71.897  431.79

111     71.503  432.45

112     71.116  432.15

113     70.741  420.71

114     70.3    427.26

115     69.935  419.76

116     69.572  407.28

117     69.148  408.04

118     68.796  393.71

119     68.448  403.74

120     68.114  408.8

121     67.717  401.26

122     67.374  400.81

123     67.037  401.89

124     66.741  408.68

125     66.416  398.49

126     66.015  414.14

127     65.373  419.78

128     64.769  426.82

129     64.109  418.42

130     63.44   446.32

131     62.772  451.55

132     62.111  473.27

133     61.508  499.69

134     60.908  523.66

135     60.219  551.47

136     59.699  593.53

137     59.119  608.69

138     58.547  658.08

139     57.992  712.27

140     57.483  769.4

141     56.969  826.48

142     56.472  896.05

143     55.989  957.57

144     55.513  1065.1

145     55.088  1114.1

146     54.651  1195

147     54.237  1271.5

148     53.836  1355.6

149     53.318  1483.2

150     52.701  1690

151     52.08   2245.9

152     51.431  2470.4

153     50.877  2719.1

154     50.298  2957.5

155     49.74   3155.2

156     49.2    3279.4

157     48.702  3546.4

158     48.182  3741

159     47.681  4021

160     47.213  4015.1

161     46.768  4304.7

162     46.368  4127.9

163     45.956  4530.9

164     45.55   4802.9

165     45.157  5047.4

166     44.799  4804.3

167     44.43   5164.1

168     44.078  4781

169     43.727  5175.5

170     43.384  5708.6

171     43.079  5679.6

172     42.899  5161.8

173     42.719  5399.1

174     42.547  5483

175     42.253  4839.4

176     41.962  5360.7

177     41.691  5622

178     40.602  5772.3

 

 

Test Data 2

Test Data 3

Test Data 4

Test Data 5

No      x1       x2        x3       x4      y

No      x      y

No      x1     x2       x3       x4      y

No.    x        y       z

1       15100   29000   508.0   180     3.40

2       20500   43350   453.7   141     3.00

3       80000   92610   487.9   132     2.70

4       91500   142775  572.3   182     3.37

5       82500   2123160 455.7   113     6.89

6       20000   227800  481.3   170     5.03

7       17800   140000  541.3   179     3.55

8       3900    15980   538.6   186     2.72

9       17300   223200  460.6   100     4.05

10      25700   229400  393.1   133     3.22

11      49400   424500  373.9   106     2.65

12      40700   561700  482.8   107     1.91

13      77000   563600  482.1   140     3.00

14      92900   557600  415.1   121     1.31

15      63300   528300  536.7   144     2.33

16      51600   488940  385.1   154     3.55

17      60000   480500  412.2   111     3.37

18      70000   530500  567.2   139     2.55

1       80.0    6.64

2       140.9   11.54

3       204.7   15.89

4       277.9   20.16

5       356.8   21.56

6       453.0   21.69

7       505.6   22.66

8       674.5   23.15

9       802.32  18.16

10      936.04  16.81

1       14      1.38    -34     16      582

2       10      0.52    -29     2       458

3       13      1.70    -32     13      559

4       24      0.80    24      1       322

5       12      1.83    41      11      399

6       6       1.77    -50     7       523

7       18      1.23    27      4       322

8       -10     0.28    -8      6       358

9       0       1.20    66      6       354

10      14      1.75    -60     6       574

11      12      1.78    -70     7       489

12      -18     1.37    -15     0       232

13      16      1.38    0       4       440

14      -4      0.29    -9      -7      421

15      -23     1.12    -12     -14     181

16      5       1.52    0       10      426

17      -16     0.63    34      1       364

18      -1      1.32    22      -7      375

19      -18     1.18    4       -11     224

20      8       1.50    -11     5       514

21      -8      1.43    4       -12     381

22      -11     0.74    10      0       275

23      -19     1.07    -5      0       426

1       500     25      1.5

2       500     50      2.25

3       500     100     3.15

4       500     200     4.0

5       500     300     4.2

6       500     400     4.3

7       1000    25      1.45

8       1000    50      2.35

9       1000    100     3.95

10      1000    200     6.95

11      1000    300     8.15

12      1000    400     8.4

13      1500    25      1.45

14      1500    50      2.45

15      1500    100     4.15

16      1500    200     7.45

17      1500    300     10.65

18      1500    400     11.85

19      2000    25      1.45

20      2000    50      2.5

21      2000    100     4.2

22      2000    200     7.75

23      2000    300     11.45

24      2000    400     14.3

 

 

Test Data 6

Test Data 7

Test Data 8

Test Data 9

No      x      y

No      x      y    z

No      x1      x2               x3          y

No      x      y

1       1.0     8.2

2       2.0     4.6

3       3.0     4.3

4       4.0     4.6

5       5.0     5.1

6       6.0     5.5

7       7.0     5.7

8       8.0     5.5

9       9.0     5.0

10      10.0    3.8

1       4332    26.94   43.70

2       4697    23.64   44.50

3       5062    25.19   47.70

4       5428    28.60   52.30

5       5793    28.74   54.21

6       6158    29.33   55.58

7       6523    32.92   55.70

8       6889    31.87   57.70

9       7254    33.07   58.60

10      7619    29.36   60.24

11      7984    27.96   59.13

12      8350    30.18   57.00

13      8715    37.84   57.30

14      9080    38.86   59.00

15      9445    35.18   60.20

16      9811    28.81   61.80

17      10176   34.57   63.17

18      10541   37.49   66.23

19      10906   29.30   61.80

20      11272   32.47   62.03

21      11637   38.24   65.30

1       34.9    0.043378        8       0.996556

2       34.9    0.216888        8       0.985708

3       34.9    0.433776        8       0.973826

4       58.2    0.026027        8       0.999409

5       58.2    0.130133        8       0.99817

6       58.2    0.260265        8       1.000176

7       93.1    0.016267        8       0.995131

8       93.1    0.081333        8       1.009887

9       93.1    0.162666        8       1.008251

10      34.9    0.043378        20      0.835576

11      34.9    0.216888        20      0.777734

12      34.9    0.433776        20      0.715483

13      58.2    0.026027        20      0.854949

14      58.2    0.130133        20      0.822743

15      58.2    0.260265        20      0.784273

16      93.1    0.016267        20      0.85902

17      93.1    0.081333        20      0.841512

18      93.1    0.162666        20      0.81895

19      34.9    0.043378        40      0.387322

20      34.9    0.216888        40      0.338941

21      34.9    0.433776        40      0.293558

22      58.2    0.026027        40      0.342388

23      58.2    0.130133        40      0.311761

24      58.2    0.260265        40      0.280112

25      93.1    0.016267        40      0.308071

26      93.1    0.081333        40      0.287257

27      93.1    0.162666        40      0.264443

1       27.25   1

2       27.75   3

3       28.25   6

4       28.75   13

5       29.25   18

6    &