Re: It would be nice to have DiagonalMatrix accept a matrix as building
- To: mathgroup at smc.vnet.net
- Subject: [mg113536] Re: It would be nice to have DiagonalMatrix accept a matrix as building
- From: "Nasser M. Abbasi" <nma at 12000.org>
- Date: Mon, 1 Nov 2010 05:02:27 -0500 (EST)
On 10/31/2010 6:47 AM, Patrick Scheibe wrote:
> Hi,
>
> aehmm, what about
>
> SparseArray[Band[{1, 1}] -> {b,b,b,b,b,b}]
>
> where b={{1, 2}, {3, 4}}?
> Takes me about 5 seconds to type. So why care that DiagonalMatrix
> can't do it?
>
> Cheers
> Patrick
>
Well, if you wanted to repeat the block 200 times, you probably do not
want to sit and type 'b' 200 times :)
But using ConstantArray, like Zach just mentioned is what I did not know
about. His solution:
SparseArray[Band[{1, 1}] -> ConstantArray[block, {nBlocks}]]
is good enough so not to require special option for DiagonalMatrix. So
this issue is closed for me. I'll use ConstantArray for this.
Thanks for everyone input on this.
--Nasser