Subroutine CUBIC_BOND

Constrain a bond length to the time dependent quantity

$$at^3 + bt^2 + ct + d$$

where $t$ is clamped to the range $[t_{init},t_{final}]$

• data(1:4) = (/ a,b,c,d /)
• data(5) = initial time $t_{init}$
• data(6) = final time $t_{final}$

The constraint function is:

$$\begin{array}{l} C = \vert\mathbf{r}_1 - \mathbf{r}_2\vert^2 - l^2 \\ l = at^3 + bt^2 + ct + d \end{array}$$

pos, velo, data -- real(dp), dimension(:), intent(in)

t -- real(dp), intent(in)

C -- real(dp), intent(out)

dC_dr -- real(dp), dimension(size(pos)), intent(out)

dC_dt -- real(dp), intent(out)

PLANE subroutine