# Last edited on 2021-07-31 15:28:15 by jstolfi

from gauss_bell import gauss_bell
from basis_sample import basis_sample
  
def basis_2d_gauss_sample(c, r, s):
  # Evaluats at the sample points {s} the Gauss bell basis functions whose
  # centroids are in {c} and whose radii are in {r}.
  #
  # Both the centroid and radius of each basis element must be a 2-tuple of floats.
  #
  # Returns a list {B} of {nf} lists, each element being a list of
  # {ns=len(s)} floats; such that {B[i][k]} is the 2d Gauss bell basis
  # element with centroid {c[i]} and radius {r[i]} evaluated at the point {s[k]}.

  nb = len(c);
  
  def basis_gauss(i, p):
    cxi,cyi = c[i]
    rxi,ryi = r[i]
    gx = gauss_bell((p[0]-cxi)/rxi)
    gy = gauss_bell((p[1]-cyi)/ryi)
    Bp = gx*gy
    return Bp;
    # ......................................................................
    
  B = basis_sample(nb, basis_gauss, s);
  return B
  # ----------------------------------------------------------------------