[SciPy-Dev] Pole placement

[SUPSI]

Pole placement without complex poles is not usable in praxis. Usaually 
we put all the poles on the bandwidth circle, chhosing damping factors 
to have 3%-5% of overshooting.

At present, I'm using a pole plecement routine combined with a Fortran 
wrapper calling the procedures from an old slycot library. This the same 
solution implemented in Scicoslab, NSP and I think scilab too.

The good conditioning of the results is demostrated by a set of 
practical implementations on real plants in our laboratory at the SUPSI.

Best regards

Roberto

On 12/05/2014 06:43 PM, Irvin Probst wrote:
> Hi all,
> I have finished a new version of a tentative place function for Scipy 
> with Yang Tits' algorithm (improvement over KNV method 0), the user 
> can choose between both Yang Tits or KNV at runtime (method="YT" or 
> method="KNV0"). See http://drum.lib.umd.edu/handle/1903/5598
>
> I think YT is what Slicot uses but this time I played it safe and I 
> did not check the source code, this implementation is 100% original 
> (with all that it implies regarding bugs...).
>
> Once again only real poles are supported, rough tests show that YT 
> gives better conditioning of the eigen vectors of (A-BK) on 50% of my 
> tests, KNV 25% and they are equal otherwise. Please not that these are 
> only rough tests with dumb random matrices, it is not a claim over the 
> respective performances of these algorithms in real life, and I'm 
> pretty sure my implementation does not give results as clean as the 
> original matlab/fortran code polished over decades does (I plan to 
> test that later).
>
> Is there a documentation/tutorial anywhere about what should or should 
> not be done when trying to include code into Scipy ? I mean coding 
> style, patch format and so on.
>
> Regards.
>
> P.S: I did not attach my code to this email as it is not yet clean 
> enough but I would be pleased to send it to anyone who requests it
>
>
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> SciPy-Dev at scipy.org
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python module _wrapper ! in 
    interface  ! in :_wrapper
        subroutine ssxmc(n,m,a,na,b,ncont,indcon,nblk,z,wrka,wrk1,wrk2,iwrk,tol,mode)
            integer, required,check(shape(a,1)==n),depend(a) :: n=shape(a,1)
            integer, required,check(shape(b,1)==m),depend(b) :: m=shape(b,1)
            double precision intent(in, out, copy), dimension(na,n) :: a
            integer, required,check(shape(a,0)==na),depend(a) :: na=shape(a,0)
            double precision intent(in, out, copy), dimension(na,m),depend(na) :: b
            integer intent(out) :: ncont
            integer intent(out) :: indcon
            integer intent(out), dimension(n),depend(n) :: nblk
            double precision intent(out), dimension(na,n),depend(na,n) :: z
            double precision dimension(n,m),depend(n,m) :: wrka
            double precision dimension(m),depend(m) :: wrk1
            double precision dimension(m),depend(m) :: wrk2
            integer dimension(m),depend(m) :: iwrk
            double precision :: tol
            integer :: mode
        end subroutine ssxmc
        subroutine polmc(nm,ng,n,m,a,b,g,wr,wi,z,inc,invr,ierr,jpvt,rm1,rm2,rv1,rv2,rv3,rv4)
            integer, optional,check(shape(a,0)==nm),depend(a) :: nm=shape(a,0)
            integer, optional ,check(shape(g,0)==ng),depend(g) :: ng=shape(g,0)
            integer, optional,check(shape(a,1)==n),depend(a) :: n=shape(a,1)
            integer, optional,check(shape(b,1)==m),depend(b) :: m=shape(b,1)
            double precision intent(in,out, copy), dimension(nm,n) :: a
            double precision intent(in,out, copy), dimension(nm,m),depend(nm) :: b
            double precision intent(in,out,copy), dimension(ng,n),depend(n) :: g
            double precision dimension(n),depend(n) :: wr
            double precision dimension(n),depend(n) :: wi
            double precision intent(in,out,copy), dimension(nm,n),depend(nm,n) :: z
            integer :: inc
            integer dimension(n),depend(n) :: invr
            integer intent(out) :: ierr
            integer intent(out), dimension(m),depend(m) :: jpvt
            double precision dimension(m,m),depend(m,m) :: rm1
            double precision dimension(m,*),depend(m) :: rm2
            double precision dimension(n),depend(n) :: rv1
            double precision dimension(n),depend(n) :: rv2
            double precision dimension(m),depend(m) :: rv3
            double precision dimension(m),depend(m) :: rv4
        end subroutine polmc
    end interface 
end python module _wrapper