Re: [ublas] LAPACK Bindings HSEQR addition

From: Jeremy Conlin (jeremit0_at_[hidden])
Date: 2008-05-31 19:58:59

Thank you both Karl and Thomas, I'll certainly use those suggestions.  I
won't have much of a chance to look at this again until Wednesday of next
week.  It's great to have people to help out the new guys.
Thanks,
Jeremy

On Sat, May 31, 2008 at 1:17 PM, Karl Meerbergen <
karl.meerbergen_at_[hidden]> wrote:

> Hi Jeremy,
>
> There is a lapack bindings auxiliary, called workspace1 and workspace2,
> together with optimal_workspace and minimal_workspace. Often lapack
> subprograms have a minimum size of the workspace and an optimal size that
> allows for use of blas3 calls.
>
> See ormqr, steqr, sytrd, syev, heev, ... as examples.
>
> Good luck,
>
> Karl
>
>
>
> Thomas Klimpel wrote:
>
>> Hello Jeremy,
>>
>>
>>
>>> Can someone look at my attempt and either tell me to give up or how to
>>> proceed?
>>>
>>>
>>
>> Have a look at hbev.hpp (and/or hees.hpp). The following construction is
>> typically used to differentiate between the different types (e.g. double vs.
>> complex<double>), because real versions just have one workspace argument,
>> while complex versions have two workspace arguments.
>>
>>    namespace detail {
>>       template <int N>
>>       struct Hbev{};
>>
>>
>>       /// Handling of workspace in the case of one workarray.
>>       template <>
>>       struct Hbev< 1 > {
>>       ...
>>       };
>>       /// Handling of workspace in the case of two workarrays.
>>       template <>
>>       struct Hbev< 2 > {
>>       ...
>>       };
>>
>>       template <typename AB, typename Z, typename W, typename Work>
>>       int hbev( char const jobz, AB& ab, W& w, Z& z, Work work ) {
>>         ...         int info ;
>>         detail::Hbev< n_workspace_args<value_type>::value >() (jobz,
>>                       ...);
>>         return info ;
>>       } // hbev()
>>
>>
>>
>> I have two other comments:
>>
>> - please add a copyright line like
>>  * Copyright Jeremy Conlin 2008
>>
>> - don't use "unsigned int" in lapack.h
>>
>> Regards,
>> Thomas
>>
>>
>> -----Ursprüngliche Nachricht-----
>> Von: ublas-bounces_at_[hidden] im Auftrag von Jeremy Conlin
>> Gesendet: Fr 30.05.2008 21:48
>> An: ublas mailing list
>> Betreff: [ublas] LAPACK Bindings HSEQR addition
>>  I have made a start with creating the bindings for the HSEQR functions
>> for
>> LAPACK.  They are not complete; I was hoping someone could provide some
>> feedback and advice.  Currently I have implemented only one (double) of
>> the
>> four (float, double, complex<float>, complex<double>) versions.  I have
>> tried to follow the example in the geev.hpp file for much of my work.
>> My current problem is trying to differentiate between the different types
>> (e.g. double vs. complex<double>).  I know this can be handled with
>> templates, but I'm not exactly sure how this should be taken care of.  Can
>> someone look at my attempt and either tell me to give up or how to
>> proceed?
>>
>> I have attached a diff file from my version to the current svn version as
>> well as my added hseqr.hpp file and a simple test main.
>>
>> Thanks,
>> Jeremy Conlin
>>
>>  ------------------------------------------------------------------------
>>
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>>
>>
>
>
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