On Wed, Aug 24, 2022 at 09:42:54AM +0200, Ralf Hemmecke wrote:
>
> Still there is the question, how am I supposed to take the result apart for
> further computation. That should be explained somewhere. You cannot expect
> your users to know how the internals of Expression(Integer) are to be
> handled.
Well, at top level this is general expression, not different
from other expressions. You can get at details using 'kernels',
'operator' and 'arguments':
(8) -> guess([2,3,5,7,11,13,17,19])
(8)
[
s - 1 p - 1 s - 1
n - 1 8 7 6
--+ ++-++ --+ ++-++
> | | > - | | [f(p ): (p - 1)f(p ) + p - 1 = 0] + 2
--+ | | --+ | | 5 5 5 5
s = 0 p = 0 s = 0 p = 0
8 7 6 5
+
2
]
Type: List(Expression(Integer))
(9) -> res := %(1)
(9)
s - 1 p - 1 s - 1
n - 1 8 7 6
--+ ++-++ --+ ++-++
> | | > - | | [f(p ): (p - 1)f(p ) + p - 1 = 0] + 2 + 2
--+ | | --+ | | 5 5 5 5
s = 0 p = 0 s = 0 p = 0
8 7 6 5
Type: Expression(Integer)
(10) -> kernels(res)
(10)
s - 1 p - 1 s - 1
n - 1 8 7 6
--+ ++-++ --+ ++-++
[ > | | > - | | [f(p ): (p - 1)f(p ) + p - 1 = 0] + 2]
--+ | | --+ | | 5 5 5 5
s = 0 p = 0 s = 0 p = 0
8 7 6 5
Type: List(Kernel(Expression(Integer)))
(11) -> k1 := kernels(res)(1)
(11)
s - 1 p - 1 s - 1
n - 1 8 7 6
--+ ++-++ --+ ++-++
> | | > - | | [f(p ): (p - 1)f(p ) + p - 1 = 0] + 2
--+ | | --+ | | 5 5 5 5
s = 0 p = 0 s = 0 p = 0
8 7 6 5
Type: Kernel(Expression(Integer))
(12) -> operator(k1)
(12) %defsum
Type: BasicOperator
(13) -> argument(k1)
(13)
p - 1 s - 1
%M - 1 7 6
++-++ --+ ++-++
[ | | > - | | [f(p ): (p - 1)f(p ) + p - 1 = 0] + 2, %M, s ,
| | --+ | | 5 5 5 5 8
p = 0 s = 0 p = 0
7 6 5
0, n - 1]
Type: List(Expression(Integer))
For inner reccurence it is a bit more tricky as several interesting
things are hidden inside operator.
One can better see structure converting to InputForm:
(14) -> res::InputForm
(14)
(+
(sum
(product
(+
(sum
(* - 1
(product (rootOfRec %J (%inforec2))
(equation %J (SEGMENT 0 (+ %K - 1))))
)
(equation %K (SEGMENT 0 (+ %L - 1))))
2)
(equation %L (SEGMENT 0 (+ %M - 1))))
(equation %M (SEGMENT 0 (+ n - 1))))
2)
Type: InputForm
You can also use OutputForm, but it is more verbose and slightly
less informative. Note that OutputForm is OK, display problems
are in formatters.
--
Waldek Hebisch
--
You received this message because you are subscribed to the Google Groups
"FriCAS - computer algebra system" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To view this discussion on the web visit
https://groups.google.com/d/msgid/fricas-devel/20220824125345.GA10024%40fricas.math.uni.wroc.pl.
