Mathematica 9 is now available
Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
1999
*January
*February
*March
*April
*May
*June
*July
*August
*September
*October
*November
*December
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 1999

[Date Index] [Thread Index] [Author Index]

Search the Archive

RE: latest on Mathematica 4 bug

  • To: mathgroup at smc.vnet.net
  • Subject: [mg19072] RE: latest on Mathematica 4 bug
  • From: "Ersek, Ted R" <ErsekTR at navair.navy.mil>
  • Date: Thu, 5 Aug 1999 01:34:57 -0400
  • Sender: owner-wri-mathgroup at wolfram.com

Below I provide another example where the version 4.0 bug 
noted by (slinger at signal.dera.gov.uk) causes problems.

In[1]:=
a1=Range[-2.5, -1.5, 1];
a2=Sqrt[a1]

Out[2]=
{0.+1.58114 I, 0.+1.22474 I}


In[3]:=
Part[a2,1]= 3.2+9.8*I;
a2

Out[4]=
{3.2+3.2 I, 0.+1.22474 I}

Notice the result above is wrong.  As indicated earlier this seems to crop
up when you use Part and Set to change an element of a complex packed array.
There are many functions that can return a complex packed array, so beware.
Instead I would use ReplacePart as below.


In[5]:=
a2=Sqrt[a1];
ReplacePart[a2, 3.2+9.8*I, 1]

Out[6]=
{3.2+9.8 I, 0.+1.22474 I}

---------------------
Regards,
Ted Ersek


  • Prev by Date: Re: equaltity of lists
  • Next by Date: Re: Conversion of output
  • Previous by thread: (long) Re: need help.
  • Next by thread: HELP: Mathlink and InterpolatingFunction