Regress.NLinRegress Method

Overload List

#SignatureDescription
1function NLinRegress(const X: TVec; const Y: TVec; RegFun: TRegressFun; DeriveProc: TDeriveProc; const B: TVec; Method: TOptMethod; out StopReason: TOptStopReason; const Weights: TVec; const YCalc: TVec; SoftSearch: Boolean; MaxIter: Integer; Tol: Double; GradTol: Double; const Verbose: TStrings): Integer;General non-linear regression.
2function NLinRegress(const X: TVec; const Y: TVec; RegFun: TRegressFun; DeriveProc: TDeriveProc; const B: TVec; const BLowerB: TVec; const BUpperB: TVec; Method: TOptMethod; out StopReason: TOptStopReason; const Weights: TVec; const YCalc: TVec; SoftSearch: Boolean; MaxIter: Integer; Tol: Double; GradTol: Double; const Verbose: TStrings): Integer;Non-linear regression with lower and upper bounds.
3function NLinRegress(const X: TVecList; const Y: TVec; RegFun: TMultiRegressFun; DeriveProc: TMultiDeriveProc; const B: TVec; Method: TOptMethod; out StopReason: TOptStopReason; const Weights: TVec; const YCalc: TVec; SoftSearch: Boolean; MaxIter: Integer; Tol: Double; GradTol: Double; const Verbose: TStrings): Integer;General vectorized non-linear regression.
4function NLinRegress(const X: TVecList; const Y: TVec; RegFun: TMultiRegressFun; DeriveProc: TMultiDeriveProc; const B: TVec; const BLowerB: TVec; const BUpperB: TVec; Method: TOptMethod; out StopReason: TOptStopReason; const Weights: TVec; const YCalc: TVec; SoftSearch: Boolean; MaxIter: Integer; Tol: Double; GradTol: Double; const Verbose: TStrings): Integer;Non-linear regression with lower and upper bounds.

Overload 1: function NLinRegress(const X: TVec; const Y: TVec; RegFun: TRegressFun; DeriveProc: TDeriveProc; const B: TVec; Method: TOptMethod; out StopReason: TOptStopReason; const Weights: TVec; const YCalc: TVec; SoftSearch: Boolean; MaxIter: Integer; Tol: Double; GradTol: Double; const Verbose: TStrings): Integer;

General non-linear regression.

#NameDescription
1XVector of the independent variable.
2YVector of dependent variable.
3RegFunRegression function.
4DeriveProcProcedure to calculate the derivatives of RegFun. You can define the exact derivative or use Regress.NumericDerive routine as numerical approximation.
5BHolds initial estimate for regression parameters. After the call to NLinRegress b returns calculated regression parameters.
6MethodDefines which optimization method will be used to find regression parameters (see MtxVec.hlp TOptMethod type to learn more about this).
7StopReasonReturns why regression parameters search stopped (see MtxVec.hlp TOptStopReason type to learn more about different stop reasons).
8WeightsWeights (optional).
9YCalcReturns calculated values (optional).
10SoftSearchIf true, internal line search algoritm will use soft line search method. Set this parameter to true if you're using numerical approximation for derivative. If this parameter is set to false, internal line search algorithm will use exact line search method. Set this parameter to false if you're using *exact* derivative.
11MaxIterMaximum allowed numer of allowed iterations.
12TolDesired regression parameters tolerance.
13GradTolMinimum allowed gradient C-Norm.
14VerboseIf assigned, stores Fun, evaluated at each iteration step. Optionally, you can also pass TOptControl object to the Verbose parameter. This allows the optimization procedure to be interrupted from another thread and optionally also allows logging and iteration count monitoring.

Returns: Int32 - Number of iterations needed to calculate regression parameters with specified tolerance.

Remarks:

The routine fits equations to data by minimizing the sum of squared residuals :

SS = Sum [y(k) - ycalc(k)]^2 ,

where y(k) and ycalc(k) are respectively the observed and calculated value of the dependent variable for observation k. ycalc(k) is a function of the regression parameters b(0), b(1) ... Here the observed values obey the following (non-linear) equation:

y(k) = RegFun[x(k), b(0), b(1), ... ]
Y = RegFun[X,b(0),b(1), ...]

where RegFun is the regression function and b(0),..b(i) are the regression parameters.

Examples
Uses MtxExp, Math387, Regress, Optimization, MtxVecTee;
// function definition
function Eckerle4(const B: TVec; X: double): double;
begin
    Eckerle4 := B[0]/B[1] * Exp(-0.5*Sqr((X-B[2])/B[1]));
end;
procedure Example;
var x,y,b,yhat: Vector;
StopReason: TOptStopReason;
begin
    x.SetIt(false,[400.0, 405.0, 410.0, 415.0,
    420.0, 425.0, 430.0, 435.0,
    436.5, 438.0, 439.5, 441.0,
    442.5, 444.0, 445.5, 447.0,
    448.5, 450.0, 451.5, 453.0,
    454.5, 456.0, 457.5, 459.0,
    460.5, 462.0, 463.5, 465.0,
    470.0, 475.0, 480.0, 485.0,
    490.0, 495.0, 500.0]);
    y.SetIt(false,[0.0001575, 0.0001699, 0.0002350, 0.0003102,
    0.0004917, 0.0008710, 0.0017418, 0.0046400,
    0.0065895, 0.0097302, 0.0149002, 0.0237310,
    0.0401683, 0.0712559, 0.1264458, 0.2073413,
    0.2902366, 0.3445623, 0.3698049, 0.3668534,
    0.3106727, 0.2078154, 0.1164354, 0.0616764,
    0.0337200, 0.0194023, 0.0117831, 0.0074357,
    0.0022732, 0.0008800, 0.0004579, 0.0002345,
    0.0001586, 0.0001143, 0.0000710]);
    b.SetIt(false,[1.0, 10.0, 500.0]); // initial estimates
    NLinRegress(x,y,Eckerle4,nil,b,optMarquardt, StopReason,
    nil,yhat,false,300,1e-8,1e-10);
    DrawValues(x,y,Series1,false); // draw data
    DrawValues(x,yhat,Series2,false); // draw fitted values
end;
See Also: Regress.NumericDerive

Overload 2: function NLinRegress(const X: TVec; const Y: TVec; RegFun: TRegressFun; DeriveProc: TDeriveProc; const B: TVec; const BLowerB: TVec; const BUpperB: TVec; Method: TOptMethod; out StopReason: TOptStopReason; const Weights: TVec; const YCalc: TVec; SoftSearch: Boolean; MaxIter: Integer; Tol: Double; GradTol: Double; const Verbose: TStrings): Integer;

Non-linear regression with lower and upper bounds.

#NameDescription
1XVector of the independent variable.
2YVector of the dependent variable.
3RegFunRegression function.
4DeriveProcProcedure to calculate the derivatives of RegFun. You can define the exact derivative or use Regress.NumericDerive routine as numerical approximation.
5BHolds initial estimate for regression parameters. After the call to NLinRegress b returns calculated regression parameters.
6BLowerBHolds lower bounds for regression parameters. If there are no lower bounds, set BLowerB values to -INF.
7BUpperBHolds upper bounds for regression parameters. If there are no upper bounds, set BUpperB values to +INF.
8MethodDefines which optimization method will be used to find regression parameters (see MtxVec.hlp TOptMethod type to learn more about this).
9StopReasonReturns why regression parameters search stopped (see MtxVec.hlp TOptStopReason type to learn more about different stop reasons).
10WeightsWeights (optional).
11YCalcReturns calculated values (optional).
12SoftSearchIf true, internal line search algoritm will use soft line search method. Set this parameter to true if you're using numerical approximation for derivative. If this parameter is set to false, internal line search algorithm will use exact line search method. Set this parameter to false if you're using *exact* derivative.
13MaxIterMaximum allowed numer of allowed iterations.
14TolDesired regression parameters tolerance.
15GradTolMinimum allowed gradient C-Norm.
16VerboseIf assigned, stores Fun, evaluated at each iteration step. Optionally, you can also pass TOptControl object to the Verbose parameter. This allows the optimization procedure to be interrupted from another thread and optionally also allows logging and iteration count monitoring.

Returns: Int32 - Number of iterations needed to calculate regression parameters with specified tolerance.

Remarks:

General non-linear regression with lower and upper bounds for regression coefficients.

Examples
Uses MtxExp, Math387, Regress, Optimization, MtxVecTee;
// function definition
procedure Eckerle4(const B: TVec; const X: TVecList; const Y: TVec);
begin
    //= B[0]/B[1] * Exp(-0.5*Sqr((X-B[2])/B[1]));

    y.Normalize(X[0], B[2], B[1]);
    y.Sqr;
    y.Scale(-0.5);
    y.Exp;
    y.Scale(B[0]/B[1]);
end;
procedure Example;
var x0,y,b,yhat: Vector;
StopReason: TOptStopReason;
x: TVecList;
begin
    x := TVecList.Create;
    x.Add; //add

    x[0].SetIt(false,[400.0, 405.0, 410.0, 415.0,
    420.0, 425.0, 430.0, 435.0,
    436.5, 438.0, 439.5, 441.0,
    442.5, 444.0, 445.5, 447.0,
    448.5, 450.0, 451.5, 453.0,
    454.5, 456.0, 457.5, 459.0,
    460.5, 462.0, 463.5, 465.0,
    470.0, 475.0, 480.0, 485.0,
    490.0, 495.0, 500.0]);

    y.SetIt(false,[0.0001575, 0.0001699, 0.0002350, 0.0003102,
    0.0004917, 0.0008710, 0.0017418, 0.0046400,
    0.0065895, 0.0097302, 0.0149002, 0.0237310,
    0.0401683, 0.0712559, 0.1264458, 0.2073413,
    0.2902366, 0.3445623, 0.3698049, 0.3668534,
    0.3106727, 0.2078154, 0.1164354, 0.0616764,
    0.0337200, 0.0194023, 0.0117831, 0.0074357,
    0.0022732, 0.0008800, 0.0004579, 0.0002345,
    0.0001586, 0.0001143, 0.0000710]);

    b.SetIt(false,[1.0, 10.0, 500.0]); // initial estimates
    NLinRegress(x,y,Eckerle4,nil,b,optMarquardt, StopReason,
    nil,yhat,false,300,1e-8,1e-10);

    DrawValues(x[0],y,Series1,false); // draw data
    DrawValues(x[0],yhat,Series2,false); // draw fitted values

    x.Free;
end;

Overload 3: function NLinRegress(const X: TVecList; const Y: TVec; RegFun: TMultiRegressFun; DeriveProc: TMultiDeriveProc; const B: TVec; Method: TOptMethod; out StopReason: TOptStopReason; const Weights: TVec; const YCalc: TVec; SoftSearch: Boolean; MaxIter: Integer; Tol: Double; GradTol: Double; const Verbose: TStrings): Integer;

General vectorized non-linear regression.

#NameDescription
1XList of vectors of independent variable(s).
2YVector of the dependent variable.
3RegFunRegression function.
4DeriveProcProcedure to calculate the derivatives of RegFun. You can define the exact derivative or use Regress.MultiNumericDerive routine as numerical approximation.
5BHolds initial estimate for regression parameters. After the call to NLinRegress b returns calculated regression parameters.
6MethodDefines which optimization method will be used to find regression parameters (see MtxVec.hlp TOptMethod type to learn more about this).
7StopReasonReturns why regression parameters search stopped (see MtxVec.hlp TOptStopReason type to learn more about different stop reasons).
8WeightsWeights of X values (optional).
9YCalcReturns calculated values (optional).
10SoftSearchIf true, internal line search algoritm will use soft line search method. Set this parameter to true if you're using numerical approximation for derivative. If this parameter is set to false, internal line search algorithm will use exact line search method. Set this parameter to false if you're using *exact* derivative.
11MaxIterMaximum allowed numer of allowed iterations.
12TolDesired regression parameters tolerance.
13GradTolMinimum allowed gradient C-Norm.
14VerboseIf assigned, stores Fun, evaluated at each iteration step. Optionally, you can also pass TOptControl object to the Verbose parameter. This allows the optimization procedure to be interrupted from another thread and optionally also allows logging and iteration count monitoring.

Returns: Int32 - Number of iterations needed to calculate regression parameters with specified tolerance.

Remarks:

The routine fits equations to data by minimizing the sum of squared residuals :

SS = Sum [y(k) - ycalc(k)]^2 ,

where y(k) and ycalc(k) are respectively the observed and calculated value of the dependent variable for observation k. ycalc(k) is a function of the regression parameters b(0), b(1) ... Here the observed values obey the following (non-linear) equation:

y(k) = RegFun[x(k), b(0), b(1), ... ]
Y = RegFun[X,b(0),b(1), ...]

where RegFun is the regression function and b(0),..b(i) are the regression parameters.

See Also: Regress.NumericDerive

Overload 4: function NLinRegress(const X: TVecList; const Y: TVec; RegFun: TMultiRegressFun; DeriveProc: TMultiDeriveProc; const B: TVec; const BLowerB: TVec; const BUpperB: TVec; Method: TOptMethod; out StopReason: TOptStopReason; const Weights: TVec; const YCalc: TVec; SoftSearch: Boolean; MaxIter: Integer; Tol: Double; GradTol: Double; const Verbose: TStrings): Integer;

Non-linear regression with lower and upper bounds.

#NameDescription
1XList of vectors of independent variable(s).
2YVector of dependent variable.
3RegFunRegression function.
4DeriveProcProcedure to calculate the derivatives of RegFun. You can define the exact derivative or use Regress.NumericDerive routine as numerical approximation.
5BHolds initial estimate for regression parameters. After the call to NLinRegress b returns calculated regression parameters.
6BLowerBHolds lower bounds for regression parameters. If there are no lower bounds, set BLowerB values to -INF.
7BUpperBHolds upper bounds for regression parameters. If there are no upper bounds, set BUpperB values to +INF.
8MethodDefines which optimization method will be used to find regression parameters (see MtxVec.hlp TOptMethod type to learn more about this).
9StopReasonReturns why regression parameters search stopped (see MtxVec.hlp TOptStopReason type to learn more about different stop reasons).
10WeightsWeights (optional).
11YCalcReturns calculated values (optional).
12SoftSearchIf true, internal line search algoritm will use soft line search method. Set this parameter to true if you're using numerical approximation for derivative. If this parameter is set to false, internal line search algorithm will use exact line search method. Set this parameter to false if you're using *exact* derivative.
13MaxIterMaximum allowed numer of allowed iterations.
14TolDesired regression parameters tolerance.
15GradTolMinimum allowed gradient C-Norm.
16VerboseIf assigned, stores Fun, evaluated at each iteration step. Optionally, you can also pass TOptControl object to the Verbose parameter. This allows the optimization procedure to be interrupted from another thread and optionally also allows logging and iteration count monitoring.

Returns: Int32 - Number of iterations needed to calculate regression parameters with specified tolerance.

Remarks:

General non-linear regression with lower and upper bounds for regression coefficients.