Hi, Suppose I have a number of sparse matrices with the same sparsity pattern. Is there an easy way to share the pattern data among these matrices without...
Karl Meerbergen
Karl.Meerbergen@...
Jan 20, 2004 8:26 am
1341
Hi, could anyone explain me the difference between sparse_matrix.filled() and sparse_matrix.non_zeros()? I'm using ublas::generalized_vector_of_vector< double,...
Hi Karl, ... This seems to be a farily common requirement. I think I am correct in saying there is no direct support in uBLAS. It may be possible to reuse a...
... filled() returns the number of used non zeros. non_zeros() returns the number of allocated (memory for) non zeros. That means filled() <= non_zeros() and...
Gunter Winkler
guwi17@...
Jan 21, 2004 8:26 am
1344
... Gunter, do you know if this also applies to compressed matrices? Thanks...
Dear Karl, ... In my application I have the same problem. What I did, is to create my own matrix class which contails a list of pointers to matrices and an...
... AFAIK, yes. I cannot look at the code right now. But I am fairly sure. It has the same meaning for all sparse matrix types. (See .insert(i,j,value) for ...
Gunter Winkler
guwi17@...
Jan 21, 2004 3:23 pm
1347
... sure. It has ... .insert(i,j,value) for ... Yes, definitely. My example uses compressed_matrix and as Gunter explained M.filled() <= M.non_zeros() for M...
hi. can anyone explain me how to use the "noalias" assignment with ublas and where it is defined in the source code? I've not been able to find it... thank...
... Lorenzo, If you need something that works on all version of uBLAS then you can also use the older assign member functions thus: a.assign (b); Michael...
Hello guys, I was playing with the promote_traits meta-function of uBlas. Congratulations, nice job and well written. However, I had some problems when I tried...
Ok, found the answer myself :) It's because the boost::mpl library defines by default a maximum size of 10 for a meta-vector. In order to overcome this...
hi! I've got a newbie's question. Is there and operator I can use to do: a = b * c; with a, b and c vectors (instead of writing my own for cycle, of course!)? ...
Hello Lorenzo, Recent versions of uBLAS have the function element_prod (v1, v2) which compute (v1 * v2) [i] = v1 [i] * v2 [i]. These should work as you expect...
Hi, I tried to multiply two vectors storing elements of different types (floating point numbers of different precisions). Is there are way to specify the...
There should be a "filled()" function for all the vector-like types (sparse_vector, vector, matrix_row, matrix_column... ) Currently, only compressed_vector...
The inner_prod function is slow for the sparse vector types. As I reported before for sparse matrices ( http://groups.yahoo.com/group/ublas-dev/message/1317 ),...
Hello, The benchmark N2 "release" version executable for the latest version of the uBLAS library (shipped with boost-1.31.0) freezes during execution after...
Something is wrong with the following expression v3.assign(-(v1+v2)); in bench_my_vector_add::operator() (int, fast_tag) const; If I put std::cout << i <<...
... The dead slow runtime for a debug build is normal. (Tested with gcc on my slow machine). Problem release build looks to be a VC++6.0 specific. Can anyone...
... on my slow ... I know that this is normal... ;) ... will ... I've tried few sings. Here they are: //v3.assign(-v1); // no problem //v3.assign (v1 + v2); //...
Hi, ... I just got some time to look into this. My method was to trace a debug build (under gcc) and to look which algorithm is active. Test code is simply. ...
... This would certainly make the proxy types more powerful as wrappers for sparse types. However I am not sure if this is a good idea in general. I say this ...
Hi again, I'm working through as many issues as I can today! ... uBLAS has a general type promotion mechanism. It chooses the result of a uBLAS expression to...
Dear All, I am just about to commit to the uBLAS CVS (no the Boost CVS) my first major change to the uBLAS code. Previously sprase_vector/matrix use map_array...
The function you mentioned is called correctly. I looked a little bit deeper into the problem and found that just calling inner_prod takes a long time. There...
Hi, ... That's good. ... That is bad. From my own testing VC7 generally does a a good job at optimising uBLAS's inner loops. ... Now I am a little confused!...
So what exactly is matrix_vector_range doing? Looking at the documentation tells me pretty much exactly nothing. I wanted to use it to get part of a matrix...
... matrix_vector_range is an internal object which should not be used directly. Thus the documentation is a little sparse. There is a project() operator to...
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