Hi Martin,
On Tuesday, April 2, 2024 at 3:17:19 PM UTC+3 Martin R wrote:
I tried all day to make sense of the element_constructor of the
InfinitePolynomialRIng (which uses sage_eval to interpret the repr), but I
failed.
That string eval is quite curious. I have no clue why it's necessary.
However, isn't the underlying issue that the symbolic ring has no gens (and
no ngens, and no gens_dict)? I have no clue what the correct
implementation could look like but all these just throwing a RuntimeError
looks quite wrong to me. Any other implementation seems to improve the
situation:
sage: class SR_(sage.symbolic.ring.SymbolicRing):
....: def gens_dict(self): return {}
....:
sage: SR = SR_()
sage: R.<a> = InfinitePolynomialRing(SR)
sage: p = a[0].polynomial()
sage: R(p)
a_0
Alternatively,
sage: class SR_(sage.symbolic.ring.SymbolicRing):
....: def gens_dict(self): raise ValueError() # caught by the infinite
polynomial ring
[...]
sage: R(p)
ValueError: cannot convert a_0 into an element of Infinite polynomial ring
in a over Symbolic Ring - no conversion into underlying polynomial ring
I'm also no expert when it comes to the symbolic ring. But I'm on Zulip if
you want to investigate together what's going on.
julian
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