Hi!
Barry After sleeping on it, it may be ok to include these methods in
Barry Mat as methods for filling up matrices so long as in the end
Barry you end up with a Mat that you then use as an operator.
Yes that sounds like a good test to me. If the end result of the
computation is a matrix which
Hi!
Barry Certainly pointwise addition is the same as adding two operators
Barry together (PETSc has this with MatAXPY), but what about, for example,
Barry pointwise multiply?
Pointwise multiply is the Hadamard product of two matrices matrix. You
have something like MatGetRowMax which strictly
Simon Burton simon at arrowtheory.com writes:
Oh, that should probably read:
exp( -1/2\sigma^{2} ||x1_{i} - x2_{j}||_{2}^{2})
And when we vectorize this operation:
||x1_i - x2_j||^2 = ||x1_i||^2 + ||x2_i||^2 + 2*(x1_i,x2_j)
and the last term is the ip matrix.
It seems that this
I withdraw my concern for the (I thought) possible mislocation
of the various operations on Matrices. So folks should feel
free to begin to add them.
Barry
On Sat, 20 Aug 2005, S V N Vishwanathan wrote:
Hi!
Barry After sleeping on it, it may be ok to include these methods in
Barry
Is there a way to simulate a MatSet (like VecSet) ?
Simon.
--
Simon Burton, B.Sc.
Licensed PO Box 8066
ANU Canberra 2601
Australia
Ph. 61 02 6249 6940
http://arrowtheory.com
Hi!
BTW: possibly related note, are you using dense matrices sometimes
to represent just 2-arrays; that is, not as representations of linear
operators. If so, I do not think this is the correct approach! Conceptually
PETSc Mat's are linear operators I think it would be a big mistake to
Hi!
I am not sure I understand the fine difference. As far as we are
concerned, all the operations which we are doing (point wise addition,
addition, multiplication etc.) are on the linear operator.
Barry Certainly pointwise addition is the same as adding two operators
Barry together (PETSc
On Thu, 18 Aug 2005 22:49:29 -0500 (CDT)
Barry Smith bsmith at mcs.anl.gov wrote:
What is x1, x2 and ip?
Barry
x1 and x2 are 2-arrays; their rows are the 'sample' vectors.
ip is the matrix of all inner products from x1 and x2.
Simon.
--
Simon Burton, B.Sc.
Licensed PO Box 8066
ANU
In terms of exp( -1/2\sigma^{2} ||x_{i} - x_{j}||_{2}^{2})
what are they?
Thanks
Barry
On Fri, 19 Aug 2005, Simon Burton wrote:
On Thu, 18 Aug 2005 22:49:29 -0500 (CDT)
Barry Smith bsmith at mcs.anl.gov wrote:
What is x1, x2 and ip?
Barry
x1 and x2 are
S V N Vishwanathan vishy at mail.rsise.anu.edu.au writes:
Hi!
BTW: possibly related note, are you using dense matrices sometimes
to represent just 2-arrays; that is, not as representations of linear
operators. If so, I do not think this is the correct approach! Conceptually
PETSc Mat's are
Simon Burton simon at arrowtheory.com writes:
On Thu, 18 Aug 2005 19:57:02 -0500
Matthew Knepley knepley at mcs.anl.gov wrote:
(d) m=exp(m) (pointwise exp)
We could add pointwise operations just like the VecPointwise*().
Matt
Yes, we need MatPointwiseMult
After sleeping on it, it may be ok to include these methods
in Mat as methods for filling up matrices so long as in the
end you end up with a Mat that you then use as an operator.
But I'd still like to see/understand a little more of the construction
process. Classically one would do that
Hi,
Along the lines of python's numarray [1], we need some way of
operating pointwise (and inner/outer operations) on Mat/Vec objects.
In particular, we need things like the following:
(a) v=add.reduce(m) (sum along rows/cols of a Mat to produce a Vec)
(b) m=add.outer(v1,v2) (sum of all
Simon Burton simon at arrowtheory.com writes:
Hi,
Along the lines of python's numarray [1], we need some way of
operating pointwise (and inner/outer operations) on Mat/Vec objects.
In particular, we need things like the following:
(a) v=add.reduce(m) (sum along rows/cols of a Mat to
Simon,
There is not because what does MatSet() mean for a sparse matrix?
Make it dense, just set all the current nonzeros, error? You tell us,
I could live with either of the later two but don't really like the
first.
Barry
BTW: possibly related note, are you using dense matrices
On Fri, 19 Aug 2005, S V N Vishwanathan wrote:
Hi!
BTW: possibly related note, are you using dense matrices sometimes
to represent just 2-arrays; that is, not as representations of linear
operators. If so, I do not think this is the correct approach! Conceptually
PETSc Mat's are
What is x1, x2 and ip?
Barry
On Fri, 19 Aug 2005, S V N Vishwanathan wrote:
Hi!
I am not sure I understand the fine difference. As far as we are
concerned, all the operations which we are doing (point wise addition,
addition, multiplication etc.) are on the linear operator.
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