CLsqFit:SetBasisFunc

The SetBasisFunc method selects the basis function to use for the fit. This function either selects one of the two built-in basis functions or specifies the name of a user-defined function declared in a script. Before writing a custom, user-defined, basis function, read the Basis Functions topic.

Syntax

CLsqFit:SetBasisFunc( sBasisFuncChoice )

sBasisFuncChoice is the name of a built-in basis function.

sBasisFuncChoice is a string giving the name of a user-provided function declared in a script.

Remarks

The value of sBasisFuncChoice is a string interpreted as follows:

"polynomial"	The built-in (default) n-dimensional polynomial basis function.
"hyperplane"	The built-in hyperplane basis function.
sFuncName	The name of a user-provided basis function declared in the script. This is case sensitive.

Examples

The following script selects the built-in hyperplane basis function.

L = new_lsqfit()	-- create a CLsqFit object
	-- no function declared, so n-dimensional polynomial used
L:SetBasisFunc("hyperplane")	-- select built-in function 2, the Hyperplane
sName = L:GetBasisFunc()
Printf( "Func= '%s'\n", sName )	-- result: Func= 'hyperplane'

The next example declares a user-defined basis function in the script. This function fits a line. Its name is passed as a string parameter to SetBasisFunc. Remember that your custom basis function name is case-sensitive.

function line( n, c )	-- declare the basis function. n is always passed as 2.
local b = {}	-- declare a local table for the basis vector
b[1] = 1	-- basis vector element [1] is 1
b[2] = c[1]	-- basis vector element [2] is c[1], the "x" coordinate
return b	-- return the basis vector
end	-- end of the basis function
L = new_lsqfit()	-- create a CLsqFit object
L:SetBasisFunc( "line" )	-- register the script function "Line"
L:SetNumCoefs(2)	-- set the number of coefs for a 1-dimensional fit.
-- add points to the fit
L:Fit()	-- fit the data
sName = L:GetBasisFunc()
Printf( "Func= '%s'\n", sName )	-- result: Func= 'line'

Syntax

Remarks

Examples

Related Topics