On entry:
THRES and
THRESP may be set to thresholds for use in the error control of
D02LAF. At each step in the numerical integration estimates of the local errors
$\mathrm{E1}\left(\mathit{i}\right)$ and
$\mathrm{E2}\left(\mathit{i}\right)$ in the solution,
${y}_{\mathit{i}}$, and its derivative,
${y}_{\mathit{i}}^{\prime}$, respectively are computed, for
$\mathit{i}=1,2,\dots ,{\mathbf{NEQ}}$. For the step to be accepted conditions of the following type must be satisfied:
If one or both of these is not satisfied then the step size is reduced and the solution is recomputed.
If
${\mathbf{THRES}}\left(1\right)\le 0.0$ on entry, then a value of
$50.0\times \epsilon $ is used for
${\mathbf{THRES}}\left(\mathit{i}\right)$, for
$\mathit{i}=1,2,\dots ,{\mathbf{NEQ}}$, where
$\epsilon $ is
machine precision. Similarly for
THRESP.