def test_hermevander(self):
# check for 1d x
x = np.arange(3)
v = herme.hermevander(x, 3)
assert_(v.shape == (3, 4))
for i in range(4):
coef = [0] * i + [1]
assert_almost_equal(v[..., i], herme.hermeval(x, coef))
# check for 2d x
x = np.array([[1, 2], [3, 4], [5, 6]])
v = herme.hermevander(x, 3)
assert_(v.shape == (3, 2, 4))
for i in range(4):
coef = [0] * i + [1]
assert_almost_equal(v[..., i], herme.hermeval(x, coef))
def test_hermevander(self) :
# check for 1d x
x = np.arange(3)
v = herme.hermevander(x, 3)
assert_(v.shape == (3,4))
for i in range(4) :
coef = [0]*i + [1]
assert_almost_equal(v[...,i], herme.hermeval(x, coef))
# check for 2d x
x = np.array([[1,2],[3,4],[5,6]])
v = herme.hermevander(x, 3)
assert_(v.shape == (3,2,4))
for i in range(4) :
coef = [0]*i + [1]
assert_almost_equal(v[...,i], herme.hermeval(x, coef))
def test_100(self):
x, w = herme.hermegauss(100)
# test orthogonality. Note that the results need to be normalized,
# otherwise the huge values that can arise from fast growing
# functions like Laguerre can be very confusing.
v = herme.hermevander(x, 99)
vv = np.dot(v.T * w, v)
vd = 1 / np.sqrt(vv.diagonal())
vv = vd[:, None] * vv * vd
assert_almost_equal(vv, np.eye(100))
# check that the integral of 1 is correct
tgt = np.sqrt(2 * np.pi)
assert_almost_equal(w.sum(), tgt)
def test_100(self):
x, w = herme.hermegauss(100)
# test orthogonality. Note that the results need to be normalized,
# otherwise the huge values that can arise from fast growing
# functions like Laguerre can be very confusing.
v = herme.hermevander(x, 99)
vv = np.dot(v.T * w, v)
vd = 1/np.sqrt(vv.diagonal())
vv = vd[:,None] * vv * vd
assert_almost_equal(vv, np.eye(100))
# check that the integral of 1 is correct
tgt = np.sqrt(2*np.pi)
assert_almost_equal(w.sum(), tgt)
def calc_pgh(ispec, wavelengths, psfparams):
'''
Calculate the pixelated Gauss Hermite for all wavelengths of a single spectrum
ispec : integer spectrum number
wavelengths : array of wavelengths to evaluate
psfparams : dictionary of PSF parameters returned by evalcoeffs
returns pGHx, pGHy
where pGHx[ghdeg+1, nwave, nbinsx] contains the pixel-integrated Gauss-Hermite polynomial
for all degrees at all wavelengths across nbinsx bins spaning the PSF spot, and similarly
for pGHy. The core PSF will then be evaluated as
PSFcore = sum_ij c_ij outer(pGHy[j], pGHx[i])
'''
#- shorthand
p = psfparams
#- spot size (ny,nx)
nx = p['HSIZEX']
ny = p['HSIZEY']
nwave = len(wavelengths)
# print('Spot size (ny,nx) = {},{}'.format(ny, nx))
# print('nwave = {}'.format(nwave))
#- x and y edges of bins that span the center of the PSF spot
xedges = np.repeat(np.arange(nx + 1) - nx // 2,
nwave).reshape(nx + 1, nwave)
yedges = np.repeat(np.arange(ny + 1) - ny // 2,
nwave).reshape(ny + 1, nwave)
#- Shift to be relative to the PSF center at 0 and normalize
#- by the PSF sigma (GHSIGX, GHSIGY)
#- xedges[nx+1, nwave]
#- yedges[ny+1, nwave]
xedges = ((xedges - p['X'][ispec] % 1) / p['GHSIGX'][ispec])
yedges = ((yedges - p['Y'][ispec] % 1) / p['GHSIGY'][ispec])
# print('xedges.shape = {}'.format(xedges.shape))
# print('yedges.shape = {}'.format(yedges.shape))
#- Degree of the Gauss-Hermite polynomials
ghdegx = p['GHDEGX']
ghdegy = p['GHDEGY']
#- Evaluate the Hermite polynomials at the pixel edges
#- HVx[ghdegx+1, nwave, nx+1]
#- HVy[ghdegy+1, nwave, ny+1]
HVx = He.hermevander(xedges, ghdegx).T
HVy = He.hermevander(yedges, ghdegy).T
# print('HVx.shape = {}'.format(HVx.shape))
# print('HVy.shape = {}'.format(HVy.shape))
#- Evaluate the Gaussians at the pixel edges
#- Gx[nwave, nx+1]
#- Gy[nwave, ny+1]
Gx = np.exp(-0.5 * xedges**2).T / np.sqrt(2. * np.pi) # (nwave, nedges)
Gy = np.exp(-0.5 * yedges**2).T / np.sqrt(2. * np.pi)
# print('Gx.shape = {}'.format(Gx.shape))
# print('Gy.shape = {}'.format(Gy.shape))
#- Combine into Gauss*Hermite
GHx = HVx * Gx
GHy = HVy * Gy
#- Integrate over the pixels using the relationship
# Integral{ H_k(x) exp(-0.5 x^2) dx} = -H_{k-1}(x) exp(-0.5 x^2) + const
#- pGHx[ghdegx+1, nwave, nx]
#- pGHy[ghdegy+1, nwave, ny]
pGHx = np.zeros((ghdegx + 1, nwave, nx))
pGHy = np.zeros((ghdegy + 1, nwave, ny))
pGHx[0] = 0.5 * np.diff(scipy.special.erf(xedges / np.sqrt(2.)).T)
pGHy[0] = 0.5 * np.diff(scipy.special.erf(yedges / np.sqrt(2.)).T)
pGHx[1:] = GHx[:ghdegx, :, 0:nx] - GHx[:ghdegx, :, 1:nx + 1]
pGHy[1:] = GHy[:ghdegy, :, 0:ny] - GHy[:ghdegy, :, 1:ny + 1]
# print('pGHx.shape = {}'.format(pGHx.shape))
# print('pGHy.shape = {}'.format(pGHy.shape))
return pGHx, pGHy
