Re: It would be nice to have DiagonalMatrix accept a matrix as building
- To: mathgroup at smc.vnet.net
- Subject: [mg113541] Re: It would be nice to have DiagonalMatrix accept a matrix as building
- From: Patrick Scheibe <pscheibe at trm.uni-leipzig.de>
- Date: Tue, 2 Nov 2010 05:00:05 -0500 (EST)
Yes, obiously but I wanted it as similar as possible to the
function documentation of "the other system"
blkdiag(a,b,c,d,...)
so that you see that you see that it's only a few letters more
even *without* built-in function..
Cheers
Patrick
On Nov 1, 2010, at 11:02 AM, Nasser M. Abbasi wrote:
> 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
>