[Octave-bug-tracker] [bug #31974] Interpreter fails to create complex numbers with Inf complex parts

[Judd Storrs]

Follow-up Comment #23, bug #31974 (project octave):

After I tested this in an old Matlab version (R2007b), I realized that R2007b
doesn't behave the way R2010a is reported to below:


R2007b>> x = Inf;
R2007b>> x * j
ans = NaN + Infi


But below it is claimed


R2010a>> x = Inf; 
R2010a>> x * j 
ans = 0 + Infi 


So, Matlab seems to have changed since the version I have access to. 

FWIW this is what I see in the old Matlab version:


$ matlab -nojvm

                              < M A T L A B >
                  Copyright 1984-2007 The MathWorks, Inc.
                         Version 7.5.0.338 (R2007b)
                               August 9, 2007

 
  To get started, type one of these: helpwin, helpdesk, or demo.
  For product information, visit www.mathworks.com.
 
>> foo(i)
real part is allocated; its value is 0
imaginary part is allocated, its value is 1
>> foo(1)
real part is allocated; its value is 1
>> foo(complex(1,0))
real part is allocated; its value is 1
imaginary part is allocated, its value is 0


So, after mxGetPr is called, the real part exists. It may of course be that
Matlab creates that field on demand either before mxGetPr() or before handing
off any value to MEX. 

As for the rest, this is what I see in R2007b, but I doubt it is helpful
because of the difference I noted above.


>> x = 1+i
x = 1.0000 + 1.0000i
>> y = -1+i
y = -1.0000 + 1.0000i
>> z = x+y
z = 0 + 2.0000i
>> Inf * z
ans = NaN +    Infi



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