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[Rcpp-devel] trans() changed in latest RcppArmadillo

2 messages · Baptiste Auguie, Dirk Eddelbuettel

Baptiste Auguie
# 
Dear list,

The latest RcppArmadillo broke some code that worked for me before,
and produces erroneous results. I have just tracked down the origin of
the problem to a change in the armadillo library: applying trans() to
complex matrices now takes the complex conjugate as well as
transposing. Using strans() restores the original behavior. I though
I'd warn other RcppArmadillo users to check their code if it uses
complex linear algebra. Rather curiously, strans() cannot be applied
on real matrices, so trans() should be kept there.

Best regards,

baptiste
Dirk Eddelbuettel
# 
Hi Baptiste,
On 30 May 2011 at 10:13, baptiste auguie wrote:
| Dear list,
| 
| The latest RcppArmadillo broke some code that worked for me before,
| and produces erroneous results. I have just tracked down the origin of
| the problem to a change in the armadillo library: applying trans() to
| complex matrices now takes the complex conjugate as well as
| transposing. Using strans() restores the original behavior. I though
| I'd warn other RcppArmadillo users to check their code if it uses
| complex linear algebra. Rather curiously, strans() cannot be applied
| on real matrices, so trans() should be kept there.

Yes, it is in the release notes:

0.2.21  2011-05-27

    o   Upgraded to Armadillo release 1.99.3 "v2.0 beta 3" 

          * stricter size checking for row and column vectors
          * added .count() member function to running_stat and running_stat_vec

0.2.20  2011-05-25

    o   Upgraded to Armadillo release 1.99.2 "v2.0 beta 2" (and 1.99.1 before)

          * faster inverse of symmetric matrices
	  * faster element access for fixed size matrices
	  * faster multiplication of tiny matrices (eg. 4x4)
	  * faster compund expressions containing submatrices
	  * added handling of arbitrarily sized empty matrices (eg. 5x0)
	  * added syl()
	  * added strans()
	  * added symmatu()/symmatl()
	  * added submatrices of submatrices
	  * htrans() has been deprecated; use trans() instead
	  * trans() now takes the complex conjugate when transposing a
            complex matrix
	  * .is_vec() now outputs true for empty matrices
	  * most functions with matrix inputs no longer throw exceptions when
            given empty matrices (eg. 5x0)

    o   Added a new subdirectory examples/ seeded with a nice Vector
        Autoregression simulation simulation example by Lance Bachmeier

    o   Rewrote armadillo_version as to no longer require an instance 
        of arma::arma_version, with tanks to Conrad for the suggestion

The trans() / strans() change is one of the reasons Conrad wants to call the
next release 2.0.0 to signal the break.  Sorry if that caught you by
surprise.  I still think it is a good thing that Conrad develops so fast and
thoroughly.  But yes, "surprises" like the one that you got may then happen
mit development versions.

Dirk