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Re: sqrt function, NaN and complex number
From: |
John W. Eaton |
Subject: |
Re: sqrt function, NaN and complex number |
Date: |
Fri, 10 Dec 2004 15:33:47 -0500 |
On 10-Dec-2004, Dmitri A. Sergatskov <address@hidden> wrote:
| John W. Eaton wrote:
|
| >
| > In any case, I don't think it is really a bug in Octave.
| >
| > What happens if you try a simple C++ program to test sqrt(NaN+NaN*i)?
| >
|
| That does seems to work OK:
|
| address@hidden divzero]$ cat test4.cc
| #include <complex>
| #include <iostream>
|
| int main()
| {
| std::complex<double> z1(1.0/0.0,1.0/0.0);
| std::complex<double> z2 = std::sqrt(z1);
| std::complex<double> z3 = std::sqrt(z2);
|
| std::cout
| << "z1: " << z1 << std::endl
| << "z2: " << z2 << std::endl
| << "z3: " << z3 << std::endl;
| return 0;
| }
|
| address@hidden divzero]$ g++ -Wall -o test4 test4.cc
| test4.cc: In function `int main()':
| test4.cc:6: warning: division by zero in `1.0e+0 / 0.'
| test4.cc:6: warning: division by zero in `1.0e+0 / 0.'
| address@hidden divzero]$ ./test4
| z1: (inf,inf)
| z2: (nan,nan)
| z3: (nan,nan)
|
| Using gcc 3.4.2
OK. The other thing to do is run Octave with gdb, then execute the
code that causes the (apparent) infinite loop, then get a backtrace to
see where it is looping.
jwe
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-------------------------------------------------------------
- sqrt function, NaN and complex number, Samir Sharshar, 2004/12/10
- Re: sqrt function, NaN and complex number, Per Persson, 2004/12/10
- Re: sqrt function, NaN and complex number, Dmitri A. Sergatskov, 2004/12/10
- Re: sqrt function, NaN and complex number, John W. Eaton, 2004/12/10
- Re: sqrt function, NaN and complex number, Dmitri A. Sergatskov, 2004/12/10
- Re: sqrt function, NaN and complex number, Dmitri A. Sergatskov, 2004/12/10
- Re: sqrt function, NaN and complex number,
John W. Eaton <=
- Re: sqrt function, NaN and complex number, Dmitri A. Sergatskov, 2004/12/10