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## sum(null matrix) becomes null matrix not zero

**From**: |
che6yoh |

**Subject**: |
sum(null matrix) becomes null matrix not zero |

**Date**: |
Thu, 27 May 93 19:50:00 BST |

Hello.
Thank you very much.
>Date: Thu, 27 May 1993 13:37:49 -0500
>From: Tianlin Wang <address@hidden>
>
> If I execute
> >>a=[]
> >>b=sum(a)
> The result becomes b=[].
> Is this specification of octave?
> I expected b became zero like MATLAB.
>
>I like b=[], because b=0 can fool people
>
> 1. The results of expm are strange.
> Does the problem occure only on my system?
>I think, octave uses eigenvectors to calculate expm, it could fail for
>some ill matrice. However, MATLAB built-in expm function uses more general
>and reliable algorithm.
>
>An octive user, University of Illinois
>
I am very glad to know that the cause of the problems was not
my installation.
I hope many users improve octave, though I can't check the
source codes.
It is a merit of freeware softwares, I think.
Yoshihiro Hashimoto
Dept. of Systems Eng., Nagoya Inst. of Tech.
address@hidden
[Now]Dept. of Chem. Eng., The Univ. of Leeds
address@hidden
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