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faster convert to numpy array

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This commit is contained in:
tqchen 2014-05-08 19:35:06 -07:00
parent a0c0fbbb61
commit 2ccd28339e
1 changed files with 9 additions and 2 deletions
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11
python/xgboost.py
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@ -22,6 +22,13 @@ xglib.XGDMatrixGetLabel.restype = ctypes.POINTER( ctypes.c_float )
xglib.XGDMatrixGetRow.restype = ctypes.POINTER( REntry ) xglib.XGDMatrixGetRow.restype = ctypes.POINTER( REntry )
xglib.XGBoosterPredict.restype = ctypes.POINTER( ctypes.c_float ) xglib.XGBoosterPredict.restype = ctypes.POINTER( ctypes.c_float )
def ctypes2numpy( cptr, length ):
# convert a ctypes pointer array to numpy
assert isinstance( cptr, ctypes.POINTER( ctypes.c_float ) )
res = numpy.zeros( length, dtype='float32' )
assert ctypes.memmove( res.ctypes.data, cptr, length * res.strides[0] )
return res
# data matrix used in xgboost # data matrix used in xgboost
class DMatrix: class DMatrix:
# constructor # constructor
@ -73,7 +80,7 @@ class DMatrix:
def get_label(self): def get_label(self):
length = ctypes.c_ulong() length = ctypes.c_ulong()
labels = xglib.XGDMatrixGetLabel(self.handle, ctypes.byref(length)) labels = xglib.XGDMatrixGetLabel(self.handle, ctypes.byref(length))
return numpy.array( [labels[i] for i in xrange(length.value)] ) return ctypes2numpy( labels, length.value );
# clear everything # clear everything
def clear(self): def clear(self):
xglib.XGDMatrixClear(self.handle) xglib.XGDMatrixClear(self.handle)
@ -138,7 +145,7 @@ class Booster:
def predict(self, data, bst_group = -1): def predict(self, data, bst_group = -1):
length = ctypes.c_ulong() length = ctypes.c_ulong()
preds = xglib.XGBoosterPredict( self.handle, data.handle, ctypes.byref(length), bst_group) preds = xglib.XGBoosterPredict( self.handle, data.handle, ctypes.byref(length), bst_group)
return numpy.array( [ preds[i] for i in xrange(length.value)]) return ctypes2numpy( preds, length.value )
def save_model(self, fname): def save_model(self, fname):
""" save model to file """ """ save model to file """
xglib.XGBoosterSaveModel( self.handle, ctypes.c_char_p(fname) ) xglib.XGBoosterSaveModel( self.handle, ctypes.c_char_p(fname) )