2.1 Special Constants

Scilab provides special constants `%i`, `%pi`,
`%e`, and `%eps` as primitives. The `%i` constant
represents ,
`%pi` is
, `%e`
is the trigonometric constant
,
and `%eps`
is a constant representing the precision of the machine (`%eps`
is the biggest number for which
). `%inf`
and `%nan` stand for ``Infinity'' and ``NotANumber'' respectively.
`%s` is the polynomial s=`poly(0,'s')` with symbol `s`.

(More generally, given a vector `rts`, `p=poly(rts,'x')`
defines the polynomial p(x) with variable `x` and such
that `roots(p)` = `rts`).

Finally boolean constants are `%t` and `%f` which stand for
``true'' and ``false'' respectively. Note that `%t` is the
same as `1==1` and `%f` is the same as `~%t`

.

These variables are considered as ``predefined''. They are protected, cannot
be deleted and are not saved by the `save` command. It is possible
for a user to have his own ``predefined'' variables by using the
`predef` command. The best way is probably to set these special variables
in his own startup file `<home dir>/.scilab`.
Of course, the user can use e.g. `i=sqrt(-1)` instead of `%i`.