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Re: Set diagonal of square matrix

• To: mathgroup at smc.vnet.net
• Subject: [mg117009] Re: Set diagonal of square matrix
• From: Oliver Ruebenkoenig <ruebenko at wolfram.com>
• Date: Mon, 7 Mar 2011 05:49:23 -0500 (EST)
• References: <201103051104.GAA29846@smc.vnet.net>

On Sat, 5 Mar 2011, Szabolcs wrote:

> Dear MathGroup members,
>
> Is there any simple way to set the diagonal of a square matrix to a
> vector (of appropriate length)?  Of course there are ways to do it,
> but I was wondering if there was a simple, one-line way.
>
>

here is one that works with SparseArray and Band

mat + SparseArray[Band[{1, 1}] -> vec - Diagonal[mat],
   Dimensions[mat]]

Oliver

• References:
  • Set diagonal of square matrix
    • From: Szabolcs <szhorvat@gmail.com>