with 64 bit win 7 and J 8.02  I have no problems

   a=. (1.1-1.1)+ i.4 4
   a
 0  1  2  3
 4  5  6  7
 8  9 10 11
12 13 14 15
   a=.a,("1) 1 2 3

   a=.a,("1) 1 2 3
   a
 0  1  2  3 1 2 3
 4  5  6  7 1 2 3
 8  9 10 11 1 2 3
12 13 14 15 1 2 3


Don Kelly


On 25/06/2014 6:28 AM, bill lam wrote:
it seems a bug in floating point numbers in-place concatenation as illustrated 
below
  a=. i.4 4
    a=. a,("1) 1 2 3
    a
  0  1  2  3 1 2 3
  4  5  6  7 1 2 3
  8  9 10 11 1 2 3
12 13 14 15 1 2 3
NB. so far correct, but for floating point numbers

NB. rubbish columns appended
a=. (1.1-1.1)+ i.4 4
    a=. a,("1) 1 2 3
    a
  0  1  2  3 1 2 3 4.58553e_72 1.5549e_259 0 0 0 0
  4  5  6  7 1 2 3           0           0 0 0 0 0
  8  9 10 11 1 2 3           1           2 3 1 2 3
12 13 14 15 1 2 3           1           2 3 1 2 3

NB. rubbish columns with strange numbers

    a=. (1.1-1.1)+ i.4 4
    ]a=. a,("1) 1 2 3
  0  1  2  3 1 2 3
  4  5  6  7 1 2 3
  8  9 10 11 1 2 3
12 13 14 15 1 2 3
    a
  0  1  2  3 1 2 3
  4  5  6  7 1 2 3
  8  9 10 11 1 2 3
12 13 14 15 1 2 3

NB. strange, if the value is used for further evaluation, the result seems 
correct.

It runs fine if not in-place , eg
  b=. a,("1) 1 2 3

Tested on j6, j7 , 32-bit windows, linux and iphone. not all combinations.
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