[General Information]

Function Name=Chapman		; name show up in the select function dialog
Brief Description=Chapman Model
Function Type=Built-in		; source type, built-in, user-defined, external dll
Function Form=Expression	; function form;
Function Source=fgroup.Chapman
Number Of Parameters=3
Number Of Independent Variables=1
Number Of Dependent Variables=1


[Fitting Parameters]

Naming Method=user-defined
Names=a,b,c
Lower bounds=--,--,--
Upper bounds=--,--,--
Meanings=coefficient,coefficient,coefficient

[Independent Variables]

x =


[Dependent Variables]

y =


[Constants]


[Formula]

y =a*(1 - exp(-b*x))^c

[Constraints]

[Parameters Initialization]
sort( x_y_curve );
smooth( x_y_curve, 2 );
a = yatxmax( x_y_curve ); 
x_y_curve = x_y_curve / a;
if( yatxmin( x_y_curve ) > 1)
  x_y_curve = ln( x_y_curve - 1.0 );
else 
  x_y_curve = ln( 1.0 - x_y_curve );
double coeff[2];
fitpoly( x_y_curve, 1, coeff);  
c = coeff[0];
b = -coeff[1];

[Initializations]


[After fitting]


[Controls]
General Linear Constraints=Off
Initialization scripts=Off
Scripts After fitting=Off

