Nonlinear Regression Preview

Nonlinear regression model:
logP=ABC+TC
Auxiliary Equations

logP=log10(P)
Boundaries
m(A)=8.752
m(B)=2035
m(C)=273
Data-Table
 TCP
1-36.71
2-19.65
3-11.510
4-2.620
57.640
615.460
726.1100
842.2200
960.6400
1080.1760

Program validated. Ready to Solve.
# Example 29 - Nonlinear Regression
# Pressure Data
# Verified Solution: A=5.76735, B=677.094, C=153.885
# Ref.: Comput. Appl. Eng. Educ. 6: 173, 1998

[
TC P
-36.7 1
-19.6 5
-11.5 10
-2.6 20
7.6 40
15.4 60
26.1 100
42.2 200
60.6 400
80.1 760
]

logP=log(P)

# nlinfit =
nlinfit logP = A-B/(C+TC)

# Initial guess of the regression model variables
m(A)= 8.752
m(B)= 2035
m(C)=273

Regression Model

logP = A-B/(C+TC)

where A, B, C are the variables to find based on logP = f(TC)

Model VariableInitial GuessValue95% confidence
A8.7525.7673466 0.152084
B2035677.09404 48.1591
C273153.88537 5.68709

R²adjRmsdVariance
0.9996880.9995990.004722810.000318642

Nonlinear Regression Fit
Chart
Nonlinear Regression logP Residuals
Chart

Data Table

 TClogPCalculated logPResidual %
1-36.70-0.010627326Infinity%
2-19.60.698970.72514420-3.745%
3-11.511.0119843-1.198%
4-2.61.301031.29173860.7142%
57.61.602061.57443411.724%
615.41.77815131.76762700.5919%
726.122.0054074-0.2704%
842.22.301032.3142893-0.5762%
960.62.602062.6105158-0.3250%
1080.12.88081362.87360150.2504%

Settings and Hints

 Name/SourceValueType
1 Algorithm LM Setting
2 Sample size 10 Setting
3 Model vars 3 Setting
4 Indep vars 1 Setting
5 Iterations 24 Setting
6 Elapsed time 0.152 ms Setting
7 #@NLR_SOLUTION_METHOD_INDEX 1 Setting
8 #@NLR_maxiter 128 Setting
9 #@NLR_miniter 1 Setting
10 Version 7.0.73 Setting
11 #@report_fix_digits = 8 Default (integer)
12 #@chart_size = 428,300 Default (array)
13 #@report_show_charts = true Default (boolean)
14 #@report_show_source = true Default (boolean)
15 #@report_show_header = false Default (boolean)
16 #@report_show_settings = true Default (boolean)
17 #@report_show_data_points = true Default (boolean)

Messages

 SeverityDescription
1Info-Infor- 2 Known vectors variables (TC, P)
2Info-Infor- 1 Explicit expressions (logP)
3Info-Infor- 3 Model Variables (, A, B, C)
4Info-Infor- Regression command: nlinfit logP = A-B/(C+TC)

Source

# Example 29 - Nonlinear Regression
# Pressure Data
# Verified Solution: A=5.76735, B=677.094, C=153.885
# Ref.: Comput. Appl. Eng. Educ. 6: 173, 1998

[
TC P
-36.7 1
-19.6 5
-11.5 10
-2.6 20
7.6 40
15.4 60
26.1 100
42.2 200
60.6 400
80.1 760
]

logP=log(P)

# nlinfit =
nlinfit logP = A-B/(C+TC)

# Initial guess of the regression model variables
m(A)= 8.752
m(B)= 2035
m(C)=273