CHEBY

The Cheby function evaluates a Chebyshev polynomial at a specific value x .

Format

Cheby ( x , x 0 , c 0 , c 1 , , c 30 )

Arguments

x
The independent variable. For example, to specify time as the independent variable, specify x as TIME.
x 0
The phase shift in the Chebychev polynomial.
c 0 , c 1 , , c 30
The coefficients in the Chebychev polynomial. Specify only as many coefficients as needed with a maximum of 31 coefficients.

Definition

(1)
Cheby  = i = 0 N c i P i ( x x 0 )    where,   P i ( x x 0 ) = 2 ( x x 0 ) P i 1 ( x x 0 ) P i 2 ( x x 0 )             N   =   Number of terms in the series ( N 30 ) with, P 0 ( x x 0 ) = 1   P 1 ( x x 0 ) = ( x x 0 )  

Example

<Force_Vector_TwoBody
     id                    = "30101"
     type                  = "ForceOnly"
     i_marker_id           = "30102031"
     j_floating_marker_id  = "30101031"
     ref_marker_id         = "30101010"
     fx_expression         = BISTOP(DX(30102030,30101010,30101010),
                             VX(30102030,30101010,30101010),0.5,9.5,10000000,2.1,1,0.001)"
     fy_expression         = "0"
     fz_expression         = "0"
  />