Use of fused memoryviews without the gil in cython implementation of fast hadamard transform (fht).

Author: felixmaximilian

examples/kernel_approximation/plot_kernel_approximation.py

@@ -143,7 +143,7 @@
 # plot the results:
 plt.figure(figsize=(8, 8))
 accuracy = plt.subplot(211)
-# second y axis for timeings
+# second y axis for timings
 timescale = plt.subplot(212)
 
 accuracy.plot(sample_sizes, nystroem_scores, label="Nystroem approx. kernel")
@@ -174,7 +174,8 @@
 
 # legends and labels
 accuracy.set_title("Classification accuracy")
-timescale.set_title("Training times")
+timescale.set_title("Training times for dataset size of " + str(n_samples) + " with dimensionality of  "
+                    + str(np.size(data, 1)))
 accuracy.set_xlim(sample_sizes[0], sample_sizes[-1])
 accuracy.set_xticks(())
 accuracy.set_ylim(np.min(fourier_scores), 1)

sklearn/utils/cyfht.pyx

@@ -18,10 +18,6 @@ cimport numpy as np
 cimport cython
 from libc.math cimport log2
 
-
-ctypedef np.double_t DTYPE_t
-
-
 def is_power_of_two(input_integer):
     """ Test if an integer is a power of two. """
     if input_integer == 1:
@@ -42,7 +38,7 @@ def pure_python_fht(array_):
                 array_[j] = temp - array_[j]
 
 
-def fht(np.ndarray[DTYPE_t] array_):
+def fht(cython.floating[::1] array_):
     """ Single dimensional FHT. """
     if not is_power_of_two(array_.shape[0]):
         raise ValueError('Length of input for fht must be a power of two')
@@ -51,9 +47,9 @@ def fht(np.ndarray[DTYPE_t] array_):
 
 
 @cython.boundscheck(False)
-cdef _fht(np.ndarray[DTYPE_t, ndim=1] array_):
+cdef void _fht(cython.floating[::1] array_) nogil:
     cdef unsigned int bit, length, _, i, j
-    cdef double temp
+    cdef cython.floating temp
     bit = length = array_.shape[0]
     for _ in xrange(<unsigned int>(log2(length))):
         bit >>= 1
@@ -64,8 +60,7 @@ cdef _fht(np.ndarray[DTYPE_t, ndim=1] array_):
                 array_[i] += array_[j]
                 array_[j] = temp - array_[j]
 
-
-def fht2(np.ndarray[DTYPE_t, ndim=2] array_):
+def fht2(cython.floating[:, ::1] array_):
     """ Two dimensional row-wise FHT. """
     if not is_power_of_two(array_.shape[1]):
         raise ValueError('Length of rows for fht2 must be a power of two')
@@ -74,9 +69,8 @@ def fht2(np.ndarray[DTYPE_t, ndim=2] array_):
 
 
 @cython.boundscheck(False)
-cdef _fht2(np.ndarray[DTYPE_t, ndim=2] array_):
-    cdef unsigned int bit, length, _, i, j, n
-    cdef double temp
+cdef void _fht2(cython.floating[:, ::1] array_) nogil:
+    cdef unsigned int n
     n = array_.shape[0]
     for x in xrange(n):
         # TODO: This call still shows up as yellow in cython -a presumably due