On 02/05/2015 03:08 AM, Waldek Hebisch wrote:
Abhinav Baid wrote:
On 02/03/2015 10:27 AM, Waldek Hebisch wrote:
Abhinav Baid wrote:
I'd like to contribute to FriCAS and hence, would like ideas for any other
code samples I could write.
Typically differential operators are written using ordinary derivative D.
But sametimes it is easier to write then in terms of different
derivative, in particular delta = xD (van Hoej uses this a lot).
Some time ago I wrote a domain implementing differantial operators
written in terms of delta (unfortunately in the output it is shown
as D, but it behaves as delta should behave). You can find this
domain at
http://math.uni.wroc.pl/~hebisch/fricas/lodo3.spad
It can be used like this:
F := Fraction(Integer)
uP := UnivariatePolynomial('x, F)
rF := Fraction(uP)
L := LinearOrdinaryDifferentialOperator3(F, uP, rF)
You can think how to convert operator from
LinearOrdinaryDifferentialOperator1 to LinearOrdinaryDifferentialOperator3
and back.
I've tried to write functions for these conversions here [1].
Are they fine?
[1] https://github.com/fandango-/spad/blob/master/task2.spad
Close. But compare:
apply(D()$L1, 0, x)
and
apply(D()$L3, 0, x)
We want to have the same operator, so applying result of convertion
should give the same result as original operator.
Oh, I should've paid closer attention to the warning you gave before
(about LODO3 having the output as plain D).
I've changed it now. [1] Is this okay?
[1] https://github.com/fandango-/spad/blob/master/task2.spad
Thanks,
Abhinav.
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