From bug-octave-request at bevo dot che dot wisc dot edu  Thu Apr  1 11:56:06 1999
Subject: Re: bug with negative numbers and power
From: "John W. Eaton" <jwe at bevo dot che dot wisc dot edu>
To: Thomas Walter <walter at pctc dot chemie dot uni-erlangen dot de>
Cc: bug-octave at bevo dot che dot wisc dot edu
Date: Thu, 1 Apr 1999 11:55:59 -0600 (CST)

On  1-Apr-1999, Thomas Walter <walter at pctc dot chemie dot uni-erlangen dot de> wrote:

| The number 'a = -8' is real not complex.  And the solution of
| the third root of '-8' has _only_ in the complex plain three solutions.
| In the real plain there is only one.

| If I interprete your lines correct:
| Does this mean if there is a wrapper function 'root (x, n)' with 'n'
| is an integer then the problem vanishes?

No.  If I remember correctly, the n-th root of any number has n solutions.

| This leads to another question:
| How to distinguish between integer and real values in octave?

I think

  if (round (x) == x)

should work.  But be careful.  Don't use != to invert the meaning of
this test if x is a vector or matrix.

jwe
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