Re: Set diagonal of square matrix
- To: mathgroup at smc.vnet.net
- Subject: [mg116973] Re: Set diagonal of square matrix
- From: Bill Rowe <readnews at sbcglobal.net>
- Date: Sun, 6 Mar 2011 05:42:44 -0500 (EST)
On 3/5/11 at 6:04 AM, szhorvat at gmail.com (Szabolcs) wrote:
>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.
Use DiagonalMatrix. For example,
In[7]:= mat = RandomInteger[10, {3, 3}]
Out[7]= {{6, 4, 3}, {7, 10, 4}, {5, 3, 3}}
In[8]:= mat + DiagonalMatrix[Range[3] - Diagonal@mat]
Out[8]= {{1, 4, 3}, {7, 2, 4}, {5, 3, 3}}