On entry: specifies whether vector or scalar error control is to be employed for the local error test in the integration.
If ${\mathbf{vectol}}=\mathrm{.TRUE.}$, vector error control will be used and you must specify values of
${\mathbf{rtol}}\left(\mathit{i}\right)$ and ${\mathbf{atol}}\left(\mathit{i}\right)$, for $\mathit{i}=1,2,\dots ,{\mathbf{neqf}}$.
Otherwise scalar error control will be used and you must specify values of just ${\mathbf{rtol}}\left(1\right)$ and ${\mathbf{atol}}\left(1\right)$.
The error test to be satisfied is of the form
where
${w}_{i}$ is defined as follows:
vectol | ${w}_{i}$ |
.TRUE. | ${\mathbf{rtol}}\left(i\right)\times \left|{y}_{i}\right|+{\mathbf{atol}}\left(i\right)$ |
.FALSE. | ${\mathbf{rtol}}\left(1\right)\times \left|{y}_{i}\right|+{\mathbf{atol}}\left(1\right)$ |
and
${e}_{i}$ is an estimate of the local error in
${y}_{i}$, computed internally.
vectol must remain unchanged on subsequent calls to
d02qwf with
${\mathbf{statef}}=\text{'C'}$ or
$\text{'R'}$.