[C++-sig] Newbie : fastest way of sending floats

[Philip Austin]

Benjamin Golinvaux writes:
 > 
 > I am not looking for the cleanest code, but for the FASTEST way to pass
 > the array of floats. I am willing to use the raw C api if needed.

The fastest way to pass an array of floats is to use Numerical Python
(http://www.pfdubois.com/numpy).  Boost supports conversions between
numpy (and its eventual successor, numarray) and python.  Here's an example of
a wrapper for a spline interpolator, which also makes use of a
boost/numpy support library available at
http://www.eos.ubc.ca/research/clouds/num_util.html

py::numeric::array splinewrap(py::numeric::array x, py::numeric::array y, 
			      double yp1, double ypn)
{
  nbpl::check_rank(x,1);
  nbpl::check_type(x,PyArray_DOUBLE);
  int xsize=nbpl::size(x);
  nbpl::check_rank(y,1);
  nbpl::check_type(y,PyArray_DOUBLE);
  int ysize=nbpl::size(y);
  assert(xsize==ysize);
  double* xptr=(double*) nbpl::data(x);
  double* yptr=(double*) nbpl::data(y);
  py::numeric::array y2=nbpl::makeNum(ysize, PyArray_DOUBLE);
  double* y2ptr=(double*) nbpl::data(y2);
  spline(xptr,yptr,ysize,yp1,ypn,y2ptr);
  return y2;
}

Regards, Phil