fix for issue 29

Author: oleksandr-pavlyk

mkl_fft/src/mklfft.c.src

@@ -287,20 +287,27 @@ __cached_notinplace_@DftiCompute_MODE@_@MKL_IN_TYPE@_@MKL_OUT_TYPE@(
 /**end repeat**/
 
 /*
- * For an array, iterating though indexes [i1, i2), fixing others to zero,
+ * For an array, iterating though indexes [i1, i2], fixing others to zero,
  * and _assuming_ these pointers form a regular lattice, compute distance
  * between adjacent pointers on that lattice.
  *
  */
 static NPY_INLINE MKL_LONG
 compute_distance(npy_intp *x_strides, npy_intp *x_shape, npy_intp x_itemsize, int x_rank, int i1, int i2, int c_contig, int f_contig) {
 
+    /* i1 equals (axis == 0), hence if (i1) {...} is equivalent to if (axis == 0) {...} */
     if (c_contig) {
+	/* Assuming
+              x_strides == (x_itemsize * prod(x_shape[k], 0 <k <= x_rank-1), ..., x_itemsize * x_shape[x_rank-1], x_itemsize)
+        */
         return (i1) ? 1 : _to_mkl_long(x_shape[x_rank-1]);
     }
 
     if (f_contig) {
-        return (i1) ? _to_mkl_long(x_shape[x_rank-1]) : 1;
+	/* Assuming
+              x_strides == (x_itemsize, x_itemsize * x_shape[0], ..., x_itemsize * prod(x_shape[k], 0<=k < x_rank-1))
+        */
+        return (i1) ? _to_mkl_long(x_shape[0]) : 1;
     }
 
     /* Right now, this is dead branch of code, since compute_distance is only called if array is ONESEGMENT, 

mkl_fft/tests/test_fft1d.py

@@ -324,6 +324,17 @@ def test_array5(self):
         f2 = mkl_fft.fft(z1.reshape(z1.shape), axis=-1)
         assert_allclose(f1, f2, atol=2e-15)
 
+    def test_array6(self):
+        """Inputs with Fortran layout are handled correctly, issue 29"""
+        z = self.az3
+        z = z.astype(z.dtype, order='F')
+        y1 = mkl_fft.fft(z, axis=0)
+        y2 = mkl_fft.fft(self.az3, axis=0)
+        assert_allclose(y1, y2, atol=2e-15)
+        y1 = mkl_fft.fft(z, axis=-1)
+        y2 = mkl_fft.fft(self.az3, axis=-1)
+        assert_allclose(y1, y2, atol=2e-15)
+
 
 class Test_mklfft_rfft(TestCase):
     def setUp(self):

mkl_fft/tests/test_fftnd.py

@@ -115,6 +115,7 @@ def test_cf_contig(self):
             r_tol, a_tol = _get_rtol_atol(ar)
             d_ccont = ar.copy()
             d_fcont = np.asfortranarray(d_ccont)
-            f1 = mkl_fft.fft(d_ccont)
-            f2 = mkl_fft.fft(d_fcont)
-            assert_allclose(f1, f2, rtol=r_tol, atol=a_tol)
+            for a in range(ar.ndim):
+                f1 = mkl_fft.fft(d_ccont, axis=a)
+                f2 = mkl_fft.fft(d_fcont, axis=a)
+                assert_allclose(f1, f2, rtol=r_tol, atol=a_tol)