Re: 3.0.2 release (mingw32 check)

[John W. Eaton]

On 26-Aug-2008, Benjamin Lindner wrote:

| I assumed it, because the output is printed as a complex number:
| 
| octave:1> mat2str([-1/3])
| ans = -0.33333333333333331
| octave:2> mat2str([-1/3,i])
| ans = [-0.33333333333333331+0i;0+1i]
| 
| In the second case, -1/3 is printed as a complex number, thus I assumed 
| it must be expanded. I guess [-1/3,i] is internally stored as a complex 
| 2x1 matrix, so every element is "expanded" to a complex number. "expand" 
| might be the wrong terminus here, "convert" would be more appropriate, 
| sorry.

I thought you were talking about -1/3 by itself, not in the context of
[-1/3, i].  In that case, Octave initially reads a list of
epxressions.  Then when evaluating the [] operator expression to
create a matrix, each element is evaluated in turn.  -1/3 is purely
real.  i is complex.  When combining the elements to make the overall
matrix, Octave notes that some elements are complex and produces a
complex matrix.  When converting reals to complex, it calls the
std::complex constructor to create the complex value.  That
constructor sets the imaginary part to zero regardless of whether the
real part is negative.  I think that is a reasonable choice.

The real problem is that we have no pure imaginary values, so i is
stored as (0,1).  I don't think the complex number negation operator
should have a special case for when the real part is zero, do you?

jwe