Changes between Version 1 and Version 3 of Ticket #15710


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Timestamp:
01/23/14 11:24:39 (8 years ago)
Author:
jdemeyer
Comment:

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  • Ticket #15710

    • Property Summary changed from sage hangs in division in cyclotomic field to Sage hangs in division of rational functions over cyclotomic field
  • Ticket #15710 – Description

    v1 v3  
    11From the [https://spreadsheets.google.com/pub?key=pCwvGVwSMxTzT6E2xNdo5fA google notebook bug reports]
    22
    3 The computation of b below hangs and cannot be interrupted.
     3This hangs and cannot be interrupted:
    44{{{
    5 q=49
    6 F.<E>=CyclotomicField(q)
    7 G = F['z,w'].fraction_field()
    8 [z,w]=G.gens()
    9 
    10 denom = (E-E^22)*(E-E^27)
    11 print denom
    12 print
    13 
    14 recip=1/denom
    15 print recip
    16 print
    17 
    18 a=w*recip
    19 print a
    20 print
    21 
    22 b=w/denom
    23 print b
    24 print
    25 
     5sage: F.<a>=CyclotomicField(49); G = F['z,w'].fraction_field(); 1/G(a^28 + a^23 - 1)
    266}}}
    277
    28 The attempt to evaluate b=w/denom hangs. But the reciprocal of the denominator is not complicated: Sage has no trouble evaluating recip=1/denom and then a=w*recip.
    29 
    30 Note that z is not involved in this computation, just in the definition in the field of rational functions.
     8The problem is likely a bug in Singular.