- vectorpostprocessorThe vectorpostprocessor on whose values we perform a least squares fit
C++ Type:VectorPostprocessorName

Description:The vectorpostprocessor on whose values we perform a least squares fit

- y_nameThe name of the dependent variable
C++ Type:std::string

Description:The name of the dependent variable

- x_nameThe name of the independent variable
C++ Type:std::string

Description:The name of the independent variable

- orderThe order of the polynomial fit
C++ Type:unsigned int

Description:The order of the polynomial fit

# LeastSquaresFit

Performs a polynomial least squares fit on the data contained in another VectorPostprocessor

## Description

`LeastSquaresFit`

is used perform a polynomial least squares fit of data provided through another VectorPostprocessor. It computes the coefficients for a polynomial of arbitrary, user-specified order that minimize the error using a standard least-squares procedure. This object provides the option of either outputting the polynomial coefficients of the least squares fit as a single vector, or outputting a user-defined number of samples from the polynomial using the fitted coefficients.

This VectorPostprocessor is closely related to the LeastSquaresFitHistory VectorPostprocessor, which performs the same type of least squares fit, but stores the results in a set of vectors that store the full history of the individual coefficients over a transient analysis.

The vectors of values of the independent () and dependent () variables on which the least squares fit is performed are provided through another VectorPostprocessor, which must provide two equally-sized vectors of data upon which to operate. The name of this VectorPostprocesor is provided using the `vectorpostprocessor`

parameter, and the names of the data vectors are provided with the `x_name`

and `y_name`

parameters. The vectors of data can be shifted and/or scaled through the use of optional parameters.

The user must define whether the output should be in the form of polynomial coefficients or samples using the `output`

parameter. If the option to output polynommial coefficients is used, they are stored in a vector named `coefficients`

. If samples are requested, the nam es of the sample vectors are the same as those of the data specified by `x_name`

and `y_name`

.

## Input Parameters

- execute_onTIMESTEP_ENDThe list of flag(s) indicating when this object should be executed, the available options include NONE, INITIAL, LINEAR, NONLINEAR, TIMESTEP_END, TIMESTEP_BEGIN, FINAL, CUSTOM.
Default:TIMESTEP_END

C++ Type:ExecFlagEnum

Description:The list of flag(s) indicating when this object should be executed, the available options include NONE, INITIAL, LINEAR, NONLINEAR, TIMESTEP_END, TIMESTEP_BEGIN, FINAL, CUSTOM.

- sample_x_maxThe maximum x value of the of samples to be output
C++ Type:double

Description:The maximum x value of the of samples to be output

- y_scale1Value used to scale y values (scaling is done after shifting)
Default:1

C++ Type:double

Description:Value used to scale y values (scaling is done after shifting)

- sample_x_minThe minimum x value of the of samples to be output
C++ Type:double

Description:The minimum x value of the of samples to be output

- y_shift0Value used to shift y values (shifting is done before scaling)
Default:0

C++ Type:double

Description:Value used to shift y values (shifting is done before scaling)

- num_samplesThe number of samples to be output
C++ Type:unsigned int

Description:The number of samples to be output

- outputCoefficientsThe quantity to output. Options are: Coefficients Samples
Default:Coefficients

C++ Type:MooseEnum

Description:The quantity to output. Options are: Coefficients Samples

- x_shift0Value used to shift x values (shifting is done before scaling)
Default:0

C++ Type:double

Description:Value used to shift x values (shifting is done before scaling)

- contains_complete_historyFalseSet this flag to indicate that the values in all vectors declared by this VPP represent a time history (e.g. with each invocation, new values are added and old values are never removed). This changes the output so that only a single file is output and updated with each invocation
Default:False

C++ Type:bool

Description:Set this flag to indicate that the values in all vectors declared by this VPP represent a time history (e.g. with each invocation, new values are added and old values are never removed). This changes the output so that only a single file is output and updated with each invocation

- x_scale1Value used to scale x values (scaling is done after shifting)
Default:1

C++ Type:double

Description:Value used to scale x values (scaling is done after shifting)

### Optional Parameters

- enableTrueSet the enabled status of the MooseObject.
Default:True

C++ Type:bool

Description:Set the enabled status of the MooseObject.

- use_displaced_meshFalseWhether or not this object should use the displaced mesh for computation. Note that in the case this is true but no displacements are provided in the Mesh block the undisplaced mesh will still be used.
Default:False

C++ Type:bool

Description:Whether or not this object should use the displaced mesh for computation. Note that in the case this is true but no displacements are provided in the Mesh block the undisplaced mesh will still be used.

- outputsVector of output names were you would like to restrict the output of variables(s) associated with this object
C++ Type:std::vector

Description:Vector of output names were you would like to restrict the output of variables(s) associated with this object

- control_tagsAdds user-defined labels for accessing object parameters via control logic.
C++ Type:std::vector

Description:Adds user-defined labels for accessing object parameters via control logic.

- allow_duplicate_execution_on_initialFalseIn the case where this UserObject is depended upon by an initial condition, allow it to be executed twice during the initial setup (once before the IC and again after mesh adaptivity (if applicable).
Default:False

C++ Type:bool

Description:In the case where this UserObject is depended upon by an initial condition, allow it to be executed twice during the initial setup (once before the IC and again after mesh adaptivity (if applicable).

- force_preauxFalseForces the GeneralUserObject to be executed in PREAUX
Default:False

C++ Type:bool

Description:Forces the GeneralUserObject to be executed in PREAUX