Changes between Version 2 and Version 3 of Ticket #8969


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Timestamp:
05/25/12 23:45:32 (9 years ago)
Author:
dsm
Comment:

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  • Ticket #8969

    • Property Keywords sd40.5 added
    • Property Status changed from new to needs_review
    • Property Authors changed from to Douglas McNeil

  • Ticket #8969 – Description

    v2 v3  
    5050}}}
    5151lines in  `symbolic_expression_from_maxima_string`.  This could be fixed by changing the replace to a regexp, or adding a hack `s = s.replace('!==', '!=')` afterwards.
    52 
    53 This deals with the obvious problem but not the underlying one, which is that the result is still IMHO underprocessed:
    54 {{{
    55 MODIFIED_sage: solve([2*x==3, x != 4], x)[[BR]][[x == (3/2), (-5/2) != 0]]
    56 
    57 when I wanted [[x == (3/2)]], or
    58 
    59 MODIFIED_sage: solve([2*x==3, x != 3/2], x)[[BR]][[x == (3/2), 0 != 0]]
    60 
    61 when I wanted [].
    62 }}}
    63 In fact, even in cases not involving "!=", it's possible for maxima output -- %union([x = 3/2,  -5/2 # 0]) --  to be insufficiently processed,IMHO:
    64 {{{
    65 MODIFIED_sage: solve([2*x==3, (x-4)!^2 > 0], x)
    66 [[x == (3/2), (-5/2) != 0]]
    67 }}}
    68 ISTM the extra information about what condition maxima used isn't worth the inconvenience of having to postprocess the solutions to see if one exists.