QUISPL

Returns the interpolated value or n-th derivative of the interpolated value of the Reference_Spline element.

Format

QUISPL(x, z, id) or QUISPL(x, 0, id, n)

Arguments

x
The independent variable of the curve.
z
The independent variable z of the surface. Use z = 0 if only one curve is being defined.
id
The ID of the Reference_Spline element.
n
The order of the derivative desired. Not applicable with surfaces. Must lie between 0 and 2.

Example

<Force_Scalar_TwoBody
   id             = "301001"
   type           = "Force"
   i_marker_id    = "10506"
   body1_id       = "105"
   j_marker_id    = "10706"
   body2_id       = "107"
   val_expression = "QUISPL(DM(10503,10703),0,301002)"
/>
<Reference_Spline
    id            = "301002"
    num_xy_pair   = "5"
    linear_extrap = "FALSE">
       0.0000000E+00  -2.2000000E+02
       2.0000000E+02  -2.2000000E+02
       2.3000000E+02  -2.2000000E+02
       3.7322400E+02  -1.1000000E+02
       5.0000000E+02  -0.1000000E+02
       5.1000000E+02  -1.2000000E+02
       6.0000000E+02  -1.3300000E+02
</Reference_Spline>

Comments

  1. QUISPL is based on a fifth order spline interpolation and produces smoother results compared to AKISPL and CUBSPL.
  2. Algorithm details can be found in "Algorithm 507: Procedures for Quintic Natural Spline Interpolation", John G. Herriot and Christian H. Reinsch, ACM Transactions on Mathematical Software, Vol 2, No 3, September 1976, Pages 281-289.