Re: symbolic true

[Colin Macdonald]

On 11/06/15 04:05, Doug Stewart wrote:
> using this code:
>
>
> clear
> syms p a b
> digits(47);
>
>   b=vpa("1.00000")
>   a=vpa("3.90000")
>   b<a
>   a<b
>
>    if ( b<a)
>     p="100"
>    else
>     p="400"
>    endif
>
> After running this p should be 100 but it isn't.
>
> The if statement always goes to the false condition!!
>
> How can I make the if statement work with a
> (sym) True

Currently, you need `if (logical (b < a))`

This is a bug in Octave: https://savannah.gnu.org/bugs/?43097

(also noted here: https://github.com/cbm755/octsympy/issues/191)

FWIW, the decision to have symbolic True/False values in Symbolic pkg 
could be revisited which would be a workaround.  But I think I did that 
to avoid corner cases like
`[x true x]`.

Colin