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match unequal symbols #635
Description
Hi!
Suppose I want to do partial fraction of many denominators (below den(x?) means 1/(k.k - x) for example).
s x,y,z, mm1,mm2;
c den,inv;
g ff1 = den(mm1)*den(mm2);
g ff2 = den(mm1)^2;
repeat id den(x?)*den(y?!{,x}) = inv(x-y)*( den(x) - den(y) );
print+s;
.end
Result:
ff1 =
+ den(mm1)*inv( - mm2 + mm1)
- den(mm2)*inv( - mm2 + mm1)
;
ff2 = 0;
ff1 is ok. But I dont want to capture terms with x==y.
Construction
id den(x?)*den(y?!{,x}) = inv(x-y)*( den(x) - den(y) );
does not make the job and ignores my check for the set.
Activity
jodavies commentedon Apr 22, 2025
This should work for you, you need the
?in the set:The restriction is best put on both patterns because you don't "know" which FORM will match first. For eg, this doesn't work:
but this does:
veretin commentedon Apr 23, 2025
Indeed this works.
Thank you!
jodavies commentedon Apr 23, 2025
I thought I remembered this being in the manual, but I can't see it there and neither in the tutorial. Let's class this as a "documentation bug" and add something.
tueda commentedon Apr 25, 2025
Maybe this one? Is the example too complicated?
https://github.com/vermaseren/form/blob/638f84b37bd15f9f3beac288d8e7ae97ee0db4f6/doc/manual/variable.tex#L542-L566
jodavies commentedon Apr 25, 2025
Ah yes, you are right, this covers what is required for this issue. Maybe it could spell out more directly that wildcards may be elements of unnamed sets (with their
?), but the information is indeed there.