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Re: problem with the octave built-in function "kron"
From: |
c. |
Subject: |
Re: problem with the octave built-in function "kron" |
Date: |
Fri, 3 May 2013 18:33:13 +0200 |
On 3 May 2013, at 18:28, Stephen Montgomery-Smith <address@hidden> wrote:
> Use speye instead of eye.
Unlike Matlab, in Octave eye uses less memory than speye:
----------------------------------------------------------------
>> a = eye (7);
>> b = speye (7);
>> whos a b
Variables in the current scope:
Attr Name Size Bytes Class
==== ==== ==== ===== =====
a 7x7 56 double
b 7x7 116 double
Total is 56 elements using 172 bytes
----------------------------------------------------------------
that's because Octave has a special class for diagonal matrices wich allows to
only store the
diagonal elements:
----------------------------------------------------------------
>> typeinfo (a)
ans = diagonal matrix
>> typeinfo (b)
ans = sparse matrix
>>
----------------------------------------------------------------
c.