fixes

nifty5/library/gridder.py

@@ -63,21 +63,21 @@ class GridderMaker(object):
 
 class _RestOperator(LinearOperator):
     def __init__(self, domain, oversampled_domain, eps):
+        from nifty_gridder import correction_factors
         self._domain = makeDomain(oversampled_domain)
         self._target = domain
         nu, nv = domain.shape
         nu2, nv2 = oversampled_domain.shape
 
+        fu = correction_factors(nu2, nu//2+1, eps)
+        fv = correction_factors(nv2, nv//2+1, eps)
         # compute deconvolution operator
-#        rng = np.arange(nu)
-#        k = np.minimum(rng, nu-rng)
-#        c = np.pi*r2lamb/nu2**2
-#        self._deconv_u = np.roll(np.exp(c*k**2), -nu//2).reshape((-1, 1))
-#        rng = np.arange(nv)
-#        k = np.minimum(rng, nv-rng)
-#        c = np.pi*r2lamb/nv2**2
-#        self._deconv_v = np.roll(
-#            np.exp(c*k**2)/r2lamb, -nv//2).reshape((1, -1))
+        rng = np.arange(nu)
+        k = np.minimum(rng, nu-rng)
+        self._deconv_u = np.roll(fu[k], -nu//2).reshape((-1, 1))
+        rng = np.arange(nv)
+        k = np.minimum(rng, nv-rng)
+        self._deconv_v = np.roll(fv[k], -nv//2).reshape((1, -1))
         self._capability = self.TIMES | self.ADJOINT_TIMES
 
     def apply(self, x, mode):
@@ -88,11 +88,11 @@ class _RestOperator(LinearOperator):
             res = hartley(res)
             res = np.roll(res, (nu//2, nv//2), axis=(0, 1))
             res = res[:nu, :nv]
-#            res *= self._deconv_u
-#            res *= self._deconv_v
+            res *= self._deconv_u
+            res *= self._deconv_v
         else:
-#            res = res*self._deconv_u
-#            res *= self._deconv_v
+            res = res*self._deconv_u
+            res *= self._deconv_v
             nu2, nv2 = self._domain.shape
             res = np.pad(res, ((0, nu2-nu), (0, nv2-nv)), mode='constant',
                          constant_values=0)

test/test_operators/test_nft.py

@@ -25,16 +25,20 @@ np.random.seed(40)
 
 pmp = pytest.mark.parametrize
 
+def _l2error(a,b):
+    return np.sqrt(np.sum(np.abs(a-b)**2)/np.sum(np.abs(a)**2))
 
+
+@pmp('eps', [1e-2, 1e-6, 1e-7, 1e-15])
 @pmp('nu', [12, 128])
 @pmp('nv', [4, 12, 128])
 @pmp('N', [1, 10, 100])
-def test_gridding(nu, nv, N):
+def test_gridding(nu, nv, N, eps):
     uv = np.random.rand(N, 2) - 0.5
     vis = np.random.randn(N) + 1j*np.random.randn(N)
 
     # Nifty
-    GM = ift.GridderMaker(ift.RGSpace((nu, nv)))
+    GM = ift.GridderMaker(ift.RGSpace((nu, nv)),eps=eps)
     # re-order for performance
     idx = GM.getReordering(uv)
     uv, vis = uv[idx], vis[idx]
@@ -48,7 +52,7 @@ def test_gridding(nu, nv, N):
     dft = pynu*0.
     for i in range(N):
         dft += (vis[i]*np.exp(2j*np.pi*(x*uv[i, 0] + y*uv[i, 1]))).real
-    assert_allclose(dft, pynu)
+    assert(_l2error(dft,pynu)<max(1e-13,10*eps))
 
 
 @pmp('eps', [1e-2, 1e-6, 1e-15])