Changes due to a modification of the same file in LIBSVM:

	use array for reading data in python/commonutil.py to lower the memory usage

diff --git a/python/commonutil.py b/python/commonutil.py
index f34b887d7be2f3fec76693c4ce27d1ba40d49dcc..881f6bb27051984d524368152997ecf68ed64f38 100644 (file)
--- a/python/commonutil.py
+++ b/python/commonutil.py
@@ -1,6 +1,7 @@
 #!/usr/bin/env python
 
 from __future__ import print_function
+from array import array
 import sys
 
 try:
@@ -21,17 +22,23 @@ def svm_read_problem(data_file_name, return_scipy=False):
        Read LIBSVM-format data from data_file_name and return labels y
        and data instances x.
        """
-       prob_y = []
-       prob_x = []
-       row_ptr = [0]
-       col_idx = []
+       if scipy != None and return_scipy:
+               prob_y = array('d')
+               prob_x = array('d')
+               row_ptr = array('l', [0])
+               col_idx = array('l')
+       else:
+               prob_y = []
+               prob_x = []
+               row_ptr = [0]
+               col_idx = []
        indx_start = 1
        for i, line in enumerate(open(data_file_name)):
                line = line.split(None, 1)
                # In case an instance with all zero features
                if len(line) == 1: line += ['']
                label, features = line
-               prob_y += [float(label)]
+               prob_y.append(float(label))
                if scipy != None and return_scipy:
                        nz = 0
                        for e in features.split():
@@ -40,10 +47,10 @@ def svm_read_problem(data_file_name, return_scipy=False):
                                        indx_start = 0
                                val = float(val)
                                if val != 0:
-                                       col_idx += [int(ind)-indx_start]
-                                       prob_x += [val]
+                                       col_idx.append(int(ind)-indx_start)
+                                       prob_x.append(val)
                                        nz += 1
-                       row_ptr += [row_ptr[-1]+nz]
+                       row_ptr.append(row_ptr[-1]+nz)
                else:
                        xi = {}
                        for e in features.split():
@@ -51,10 +58,10 @@ def svm_read_problem(data_file_name, return_scipy=False):
                                xi[int(ind)] = float(val)
                        prob_x += [xi]
        if scipy != None and return_scipy:
-               prob_y = scipy.array(prob_y)
-               prob_x = scipy.array(prob_x)
-               col_idx = scipy.array(col_idx)
-               row_ptr = scipy.array(row_ptr)
+               prob_y = scipy.frombuffer(prob_y, dtype='d')
+               prob_x = scipy.frombuffer(prob_x, dtype='d')
+               col_idx = scipy.frombuffer(col_idx, dtype='l')
+               row_ptr = scipy.frombuffer(row_ptr, dtype='l')
                prob_x = sparse.csr_matrix((prob_x, col_idx, row_ptr))
        return (prob_y, prob_x)