[Numpy-tickets] [NumPy] #646: incorrect calculation on int64 array

NumPy numpy-tickets@scipy....
Sat Jan 19 08:07:41 CST 2008


#646: incorrect calculation on int64 array
-----------------------+----------------------------------------------------
 Reporter:  latrine00  |       Owner:  somebody   
     Type:  defect     |      Status:  new        
 Priority:  high       |   Milestone:  1.0.5      
Component:  Other      |     Version:  none       
 Severity:  major      |    Keywords:  array int64
-----------------------+----------------------------------------------------
 I get curious results on array calculation in numpy 1.0.4

 Example code in python:

 {{{
 import numpy
 a = numpy.arange(0, 200, 2, dtype='int64')
 np = (a+1)**1
 print a
 print np
 }}}

 Second array np contains even numbers - should be odd only:

 {{{
 array([  0,   2,   4,   6,   8,  10,  12,  14,  16,  18,  20,  22,  24,
         26,  28,  30,  32,  34,  36,  38,  40,  42,  44,  46,  48,  50,
         52,  54,  56,  58,  60,  62,  64,  66,  68,  70,  72,  74,  76,
         78,  80,  82,  84,  86,  88,  90,  92,  94,  96,  98, 100, 102,
        104, 106, 108, 110, 112, 114, 116, 118, 120, 122, 124, 126, 128,
        130, 132, 134, 136, 138, 140, 142, 144, 146, 148, 150, 152, 154,
        156, 158, 160, 162, 164, 166, 168, 170, 172, 174, 176, 178, 180,
        182, 184, 186, 188, 190, 192, 194, 196, 198], dtype=int64)
 array([  1,   3,   5,   7,   9,  11,  12,  15,  17,  19,  20,  22,  24,
         27,  28,  30,  33,  35,  37,  39,  41,  43,  45,  47,  49,  51,
         53,  54,  57,  58,  60,  62,  64,  66,  68,  71,  72,  74,  77,
         79,  81,  82,  85,  86,  89,  91,  93,  95,  96,  99, 101, 103,
        105, 107, 108, 111, 112, 115, 117, 119, 120, 123, 124, 127, 129,
        131, 132, 135, 137, 139, 141, 142, 144, 147, 148, 151, 153, 154,
        157, 159, 161, 163, 164, 166, 168, 171, 173, 175, 176, 179, 181,
        182, 185, 187, 188, 190, 192, 194, 197, 199], dtype=int64)

 }}}

-- 
Ticket URL: <http://scipy.org/scipy/numpy/ticket/646>
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