From 518c72c9a2cfe2ffba4d574cf7422bc712275182 Mon Sep 17 00:00:00 2001
From: lambday <heavensdevil6909@gmail.com>
Date: Fri, 1 Apr 2016 02:35:42 +0530
Subject: [PATCH] removed simulate_null

---
 src/shogun/statistical_testing/MMD.cpp | 35 +++++++++++---------------
 1 file changed, 14 insertions(+), 21 deletions(-)

diff --git a/src/shogun/statistical_testing/MMD.cpp b/src/shogun/statistical_testing/MMD.cpp
index 4b4452b9a5b..fecb88666fc 100644
--- a/src/shogun/statistical_testing/MMD.cpp
+++ b/src/shogun/statistical_testing/MMD.cpp
@@ -50,12 +50,13 @@ struct CMMD::Self
 	void create_variance_job(index_t Bx);
 
 	std::pair<float64_t, float64_t> compute_statistic_variance();
+	SGVector<float64_t> sample_null();
 
 	CMMD& owner;
 
 	bool use_gpu_for_computation;
-	bool simulate_null;
 	index_t num_null_samples;
+
 	EStatisticType statistic_type;
 	EVarianceEstimationMethod variance_estimation_method;
 	ENullApproximationMethod null_approximation_method;
@@ -65,9 +66,11 @@ struct CMMD::Self
 };
 
 CMMD::Self::Self(CMMD& cmmd) : owner(cmmd),
-	use_gpu_for_computation(false), simulate_null(false), num_null_samples(0),
-	statistic_type(EStatisticType::UNBIASED_FULL), variance_estimation_method(EVarianceEstimationMethod::DIRECT),
-	null_approximation_method(ENullApproximationMethod::PERMUTATION), statistic_job(nullptr), variance_job(nullptr)
+	use_gpu_for_computation(false), num_null_samples(250),
+	statistic_type(EStatisticType::UNBIASED_FULL),
+	variance_estimation_method(EVarianceEstimationMethod::DIRECT),
+	null_approximation_method(ENullApproximationMethod::PERMUTATION),
+	statistic_job(nullptr), variance_job(nullptr)
 {
 }
 
@@ -102,7 +105,7 @@ void CMMD::Self::create_variance_job(index_t Bx)
 			variance_job = owner.get_direct_estimation_method();
 			break;
 		case EVarianceEstimationMethod::PERMUTATION:
-			switch(statistic_type)
+			switch (statistic_type)
 			{
 				case EStatisticType::UNBIASED_FULL:
 					variance_job = mmd::WithinBlockPermutation<mmd::UnbiasedFull>(Bx);
@@ -155,13 +158,6 @@ std::pair<float64_t, float64_t> CMMD::Self::compute_statistic_variance()
 
 			auto block_p_q = block_p->create_merged_copy(block_q.get());
 			SG_REF(block_p_q);
-			if (simulate_null)
-			{
-				SGVector<index_t> inds(block_p_q->get_num_vectors());
-				std::iota(inds.vector, inds.vector + inds.vlen, 0);
-				CMath::permute(inds);
-				block_p_q->add_subset(inds);
-			}
 
 			block_p = nullptr;
 			block_q = nullptr;
@@ -242,6 +238,11 @@ std::pair<float64_t, float64_t> CMMD::Self::compute_statistic_variance()
 	return std::make_pair(statistic, variance);
 }
 
+SGVector<float64_t> CMMD::Self::sample_null()
+{
+	return SGVector<float64_t>();
+}
+
 CMMD::CMMD() : CTwoSampleTest()
 {
 	self = std::unique_ptr<Self>(new Self(*this));
@@ -263,15 +264,7 @@ float64_t CMMD::compute_variance()
 
 SGVector<float64_t> CMMD::sample_null()
 {
-	SGVector<float64_t> null_samples(self->num_null_samples);
-	auto old = self->simulate_null;
-	self->simulate_null = true;
-	for (auto i = 0; i < self->num_null_samples; ++i)
-	{
-		null_samples[i] = compute_statistic();
-	}
-	self->simulate_null = old;
-	return null_samples;
+	return self->sample_null();
 }
 
 void CMMD::set_num_null_samples(index_t null_samples)