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rf_preprocessing.hxx |

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3 /* Copyright 2008-2009 by Ullrich Koethe and Rahul Nair */
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35
36 #ifndef VIGRA_RF_PREPROCESSING_HXX
37 #define VIGRA_RF_PREPROCESSING_HXX
38
39 #include <limits>
40 #include "rf_common.hxx"
41
42 namespace vigra
43 {
44
45 /** Class used while preprocessing (currently used only during learn)
46 *
47 * This class is internally used by the Random Forest learn function.
48 * Different split functors may need to process the data in different manners
49 * (i.e., regression labels that should not be touched and classification
50 * labels that must be converted into a integral format)
51 *
52 * This Class only exists in specialized versions, where the Tag class is
53 * fixed.
54 *
55 * The Tag class is determined by Splitfunctor::Preprocessor_t . Currently
56 * it can either be ClassificationTag or RegressionTag. look At the
57 * RegressionTag specialisation for the basic interface if you ever happen
58 * to care.... - or need some sort of vague new preprocessor.
59 * new preprocessor ( Soft labels or whatever)
60 */
61 template<class Tag, class LabelType, class T1, class C1, class T2, class C2>
62 class Processor;
63
64 namespace detail
65 {
66
67 /* Common helper function used in all Processors.
68 * This function analyses the options struct and calculates the real
69 * values needed for the current problem (data)
70 */
71 template<class T>
72 void fill_external_parameters(RandomForestOptions const & options,
73 ProblemSpec<T> & ext_param)
74 {
75 // set correct value for mtry
76 switch(options.mtry_switch_)
77 {
78 case RF_SQRT:
79 ext_param.actual_mtry_ =
80 int(std::floor(
81 std::sqrt(double(ext_param.column_count_))
82 + 0.5));
83 break;
84 case RF_LOG:
85 // this is in Breimans original paper
86 ext_param.actual_mtry_ =
87 int(1+(std::log(double(ext_param.column_count_))
88 /std::log(2.0)));
89 break;
90 case RF_FUNCTION:
91 ext_param.actual_mtry_ =
92 options.mtry_func_(ext_param.column_count_);
93 break;
94 case RF_ALL:
95 ext_param.actual_mtry_ = ext_param.column_count_;
96 break;
97 default:
98 ext_param.actual_mtry_ =
99 options.mtry_;
100 }
101 // set correct value for msample
102 switch(options.training_set_calc_switch_)
103 {
104 case RF_CONST:
105 ext_param.actual_msample_ =
106 options.training_set_size_;
107 break;
108 case RF_PROPORTIONAL:
109 ext_param.actual_msample_ =
110 (int)std::ceil( options.training_set_proportion_ *
111 ext_param.row_count_);
112 break;
113 case RF_FUNCTION:
114 ext_param.actual_msample_ =
115 options.training_set_func_(ext_param.row_count_);
116 break;
117 default:
118 vigra_precondition(1!= 1, "unexpected error");
119
120 }
121
122 }
123
124 /* Returns true if MultiArray contains NaNs
125 */
126 template<unsigned int N, class T, class C>
127 bool contains_nan(MultiArrayView<N, T, C> const & in)
128 {
129 for(int ii = 0; ii < in.size(); ++ii)
130 if(in[ii] != in[ii])
131 return true;
132 return false;
133 }
134
135 /* Returns true if MultiArray contains Infs
136 */
137 template<unsigned int N, class T, class C>
138 bool contains_inf(MultiArrayView<N, T, C> const & in)
139 {
140 if(!std::numeric_limits<T>::has_infinity)
141 return false;
142 for(int ii = 0; ii < in.size(); ++ii)
143 if(in[ii] == std::numeric_limits<T>::infinity())
144 return true;
145 return false;
146 }
147 } // namespace detail
148
149
150
151 /** Preprocessor used during Classification
152 *
153 * This class converts the labels int Integral labels which are used by the
154 * standard split functor to address memory in the node objects.
155 */
156 template<class LabelType, class T1, class C1, class T2, class C2>
157 class Processor<ClassificationTag, LabelType, T1, C1, T2, C2>
158 {
159 public:
160 typedef Int32 LabelInt;
161 typedef MultiArrayView<2, T1, C1> Feature_t;
162 typedef MultiArray<2, T1> FeatureWithMemory_t;
163 typedef MultiArrayView<2,LabelInt> Label_t;
164 MultiArrayView<2, T1, C1>const & features_;
165 MultiArray<2, LabelInt> intLabels_;
166 MultiArrayView<2, LabelInt> strata_;
167
168 template<class T>
169 Processor(MultiArrayView<2, T1, C1>const & features,
170 MultiArrayView<2, T2, C2>const & response,
171 RandomForestOptions &options,
172 ProblemSpec<T> &ext_param)
173 :
174 features_( features) // do not touch the features.
175 {
176 vigra_precondition(!detail::contains_nan(features), "RandomForest(): Feature matrix "
177 "contains NaNs");
178 vigra_precondition(!detail::contains_nan(response), "RandomForest(): Response "
179 "contains NaNs");
180 vigra_precondition(!detail::contains_inf(features), "RandomForest(): Feature matrix "
181 "contains inf");
182 vigra_precondition(!detail::contains_inf(response), "RandomForest(): Response "
183 "contains inf");
184 // set some of the problem specific parameters
185 ext_param.column_count_ = features.shape(1);
186 ext_param.row_count_ = features.shape(0);
187 ext_param.problem_type_ = CLASSIFICATION;
188 ext_param.used_ = true;
189 intLabels_.reshape(response.shape());
190
191 //get the class labels
192 if(ext_param.class_count_ == 0)
193 {
194 // fill up a map with the current labels and then create the
195 // integral labels.
196 std::set<T2> labelToInt;
197 for(MultiArrayIndex k = 0; k < features.shape(0); ++k)
198 labelToInt.insert(response(k,0));
199 std::vector<T2> tmp_(labelToInt.begin(), labelToInt.end());
200 ext_param.classes_(tmp_.begin(), tmp_.end());
201 }
202 for(MultiArrayIndex k = 0; k < features.shape(0); ++k)
203 {
204 if(std::find(ext_param.classes.begin(), ext_param.classes.end(), response(k,0)) == ext_param.classes.end())
205 {
206 throw std::runtime_error("RandomForest(): invalid label in training data.");
207 }
208 else
209 intLabels_(k, 0) = std::find(ext_param.classes.begin(), ext_param.classes.end(), response(k,0))
210 - ext_param.classes.begin();
211 }
212 // set class weights
213 if(ext_param.class_weights_.size() == 0)
214 {
215 ArrayVector<T2>
216 tmp((std::size_t)ext_param.class_count_,
217 NumericTraits<T2>::one());
218 ext_param.class_weights(tmp.begin(), tmp.end());
219 }
220
221 // set mtry and msample
222 detail::fill_external_parameters(options, ext_param);
223
224 // set strata
225 strata_ = intLabels_;
226
227 }
228
229 /** Access the processed features
230 */
231 MultiArrayView<2, T1, C1>const & features()
232 {
233 return features_;
234 }
235
236 /** Access processed labels
237 */
238 MultiArrayView<2, LabelInt> response()
239 {
240 return MultiArrayView<2, LabelInt>(intLabels_);
241 }
242
243 /** Access processed strata
244 */
245 ArrayVectorView < LabelInt> strata()
246 {
247 return ArrayVectorView<LabelInt>(intLabels_.size(), intLabels_.data());
248 }
249
250 /** Access strata fraction sized - not used currently
251 */
252 ArrayVectorView< double> strata_prob()
253 {
254 return ArrayVectorView< double>();
255 }
256 };
257
258
259
260 /** Regression Preprocessor - This basically does not do anything with the
261 * data.
262 */
263 template<class LabelType, class T1, class C1, class T2, class C2>
264 class Processor<RegressionTag,LabelType, T1, C1, T2, C2>
265 {
266 public:
267 // only views are created - no data copied.
268 MultiArrayView<2, T1, C1> features_;
269 MultiArrayView<2, T2, C2> response_;
270 RandomForestOptions const & options_;
271 ProblemSpec<LabelType> const &
272 ext_param_;
273 // will only be filled if needed
274 MultiArray<2, int> strata_;
275 bool strata_filled;
276
277 // copy the views.
278 template<class T>
279 Processor( MultiArrayView<2, T1, C1> features,
280 MultiArrayView<2, T2, C2> response,
281 RandomForestOptions const & options,
282 ProblemSpec<T>& ext_param)
283 :
284 features_(features),
285 response_(response),
286 options_(options),
287 ext_param_(ext_param)
288 {
289 // set some of the problem specific parameters
290 ext_param.column_count_ = features.shape(1);
291 ext_param.row_count_ = features.shape(0);
292 ext_param.problem_type_ = REGRESSION;
293 ext_param.used_ = true;
294 detail::fill_external_parameters(options, ext_param);
295 vigra_precondition(!detail::contains_nan(features), "Processor(): Feature Matrix "
296 "Contains NaNs");
297 vigra_precondition(!detail::contains_nan(response), "Processor(): Response "
298 "Contains NaNs");
299 vigra_precondition(!detail::contains_inf(features), "Processor(): Feature Matrix "
300 "Contains inf");
301 vigra_precondition(!detail::contains_inf(response), "Processor(): Response "
302 "Contains inf");
303 strata_ = MultiArray<2, int> (MultiArrayShape<2>::type(response_.shape(0), 1));
304 ext_param.response_size_ = response.shape(1);
305 ext_param.class_count_ = response_.shape(1);
306 std::vector<T2> tmp_(ext_param.class_count_, 0);
307 ext_param.classes_(tmp_.begin(), tmp_.end());
308 }
309
310 /** access preprocessed features
311 */
312 MultiArrayView<2, T1, C1> & features()
313 {
314 return features_;
315 }
316
317 /** access preprocessed response
318 */
319 MultiArrayView<2, T2, C2> & response()
320 {
321 return response_;
322 }
323
324 /** access strata - this is not used currently
325 */
326 MultiArray<2, int> & strata()
327 {
328 return strata_;
329 }
330 };
331 }
332 #endif //VIGRA_RF_PREPROCESSING_HXX
333
334
335

© Ullrich Köthe (ullrich.koethe@iwr.uni-heidelberg.de) Heidelberg Collaboratory for Image Processing, University of Heidelberg, Germany | html generated using doxygen and Python vigra 1.10.0 (Mon Nov 18 2013)