Re: [SciPy-user] Wrapping geqp3 (Rank revealing QR)

Feb. 24, 2006

      Pearu Peterson wrote:
...
On Fri, 24 Feb 2006, Nils Wagner wrote:
...
The next issues are
1. How do I handle JPVT ?
2. How do I find the size of LWORK in *geqp3 ?
Read the headers of ?geqp3.f files where the arguments of related 
subroutines are explained.
Sure. I mean the special handling inside the wrapper.
I found several ways for different routines to declare  _lwork

<_lwork=3*n-1,\0,2*n-1,\2>
  integer optional,intent(in),depend(n) :: lwork=<_lwork>
  check(<_lwork>\<=lwork) lwork

     ! <_lwork=(compute_vl||compute_vr)?4*n:3*n,\0,2*n,\2>
     integer optional,intent(in),depend(n,compute_vl,compute_vr) ::
lwork=<_lwork>
     check(lwork>=<_lwork>) :: lwork

     !
<_lwork=3*minmn+MAX(2*minmn\,MAX(maxmn\,nrhs)),\0,2*minmn+MAX(maxmn\,nrhs),\2>
     integer optional,intent(in),depend(nrhs,minmn,maxmn), &
          check(lwork>=1) &
          :: lwork=<_lwork>
          !check(lwork>=<_lwork>)

! <_lwork=n,\0,\0,\0>
     integer optional,intent(in),depend(n),check(lwork\>=<_lwork>) ::
lwork=<_lwork>
     <ftype> dimension(lwork),intent(hide,cache),depend(lwork) :: work

Which way is suitable here ?

Nils
...
...
I am willing to learn it :-)
but the contents of flapack_esv.pyf.src is somehow cryptic in many
places e.g.
callstatement
if(irange_capi==Py_None);else{irange[0]++;irange[1]++;}(*f2py_func)((compute_v?"V":"N"),(vrange_capi==Py_None?(irange_capi==Py_None?"A":"I"):"V"),(lower?"L":"U"),&n,a,&n,vrange,vrange+1,irange,irange+1,&atol,&m,w,z,&ldz,isuppz,work,&lwork,<_2=,,rwork\,&lrwork\,,\2>iwork,&liwork,&info);if(irange_capi==Py_None);else{irange[0]--;irange[1]--;}if(vrange_capi==Py_None);else
{capi_w_tmp-\>dimensions[0]=capi_z_tmp-\>dimensions[1]=m;/*capi_z_tmp-\>strides[0]=m*capi_z_tmp-\>descr-\>elsize;*/}
That is simple C code in one line and takes care of the offset between C 
and Fortran array indices:
if (irange_capi==Py_None)
  ;
else {
  irange[0]++;
  irange[1]++;
}
(*f2py_func)((compute_v?"V":"N"),
             (vrange_capi==Py_None?(irange_capi==Py_None?"A":"I"):"V"),
             (lower?"L":"U"),
             &n,a,&n,vrange,vrange+1,irange,irange+1,&atol,&m,
             w,z,&ldz,isuppz,work,&lwork,
             <_2=,,rwork\,&lrwork\,,\2>iwork,&liwork,&info);
if (irange_capi==Py_None)
  ;
else {
  irange[0]--;
  irange[1]--;
}
if (vrange_capi==Py_None)
  ;
else {
  capi_w_tmp-\>dimensions[0]=capi_z_tmp-\>dimensions[1]=m;
  /*capi_z_tmp-\>strides[0]=m*capi_z_tmp-\>descr-\>elsize;*/
}
See also numpy.distutils.from_template.__doc__.
Pearu
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