Changes between Initial Version and Version 2 of Ticket #10312


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Timestamp:
11/24/10 15:30:02 (11 years ago)
Author:
zimmerma
Comment:

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  • Ticket #10312

    • Property Cc zimmerma added
  • Ticket #10312 – Description

    initial v2  
    11The matrix constructor taking a list of rows as input is way too slow (apparently quadratic in the number of rows) compared to simply constructing a zero matrix then assigning the lines (quasi linear).
    2 
     2{{{
    33lines=[vector(QQ,[QQ.random_element() for j in xrange(500)]) for i in xrange(1000)]
    44
     
    2525  print time2
    2626  sys.stdout.flush()
    27 
     27}}}
    2828Timings:
     29{{{
    293050 0.128008 0.028002
    3031100 0.104007 0.056003
     
    4748950 13.752859 0.560035
    48491000 15.972999 0.620038
    49 
     50}}}
    5051Same problem with sparse matrices:
     52{{{
    515350 1.584099 1.188075
    5254100 3.116194 2.264142
     
    5557250 8.928558 5.756359
    5658300 11.564722 6.976436
    57 
     59}}}
    5860Same problem with block_matrix (block_matrix is slower than assigning the blocks directly).