**Bug fix: **
The 1-norm of a vector

The following bug (among others) has been fixed in patchlevel 1 (for Windows). The EC1 patch is available from Maple (http://www.maplesoft.com/patches.html). Recently-purchased copies of Maple may already have the patch installed.

The
**norm**
function in the
**linalg**
package computes various norms of vectors and matrices. In particular, if
**v**
is a vector or list and
**p >= 1**
,
**norm(v,p)**
should be the Minkowski norm for power
**p**
. Thus:

`> `
**with(linalg):**

Warning, new definition for norm

Warning, new definition for trace

`> `
**v:= vector([v1, v2]): norm(v,3);**

However, it doesn't work in Release 5 for
**p = 1**
unless
**_Envsignum0**
is set to 1.

`> `
**_Envsignum0:= '_Envsignum0';**

`> `
**norm(v,1);**

Error, (in norm) invalid vector norm, 1

`> `
**_Envsignum0:= 1: norm(v,1);**

For convenience, I have written a replacement for
**norm**
which temporarily sets
**_Envsignum0**
to 1, then calls the original
**norm**
procedure.
**_Envsignum0**
is restored to its original value when this exits. To use this bug fix, after loading the
**linalg**
package execute the command

`> `
**readlib(fixnorm)();**

At this point the
**norm**
command should work correctly.

`> `
**norm(v,1);**

**See also:**

__linalg__
,
__linalg[norm]__
,
patchlevel 1
,
__signum__

**Maple Advisor Database**
R. Israel 1998