Allow user to seed random number generator when shuffling points

This change also defaults to using random_device to see the mt19937 random
number generator.

filters/RandomizeFilter.cpp

@@ -1,5 +1,6 @@
 /******************************************************************************
  * Copyright (c) 2015, Hobu Inc. (hobu@hobu.co)
+ * Copyright (c) 2019, Bradley J Chambers (brad.chambers@gmail.com)
  *
  * All rights reserved.
  *
@@ -36,16 +37,20 @@
 namespace pdal
 {
 
-static StaticPluginInfo const s_info
-{
-    "filters.randomize",
-    "Randomize points in a view.",
-    "http://pdal.io/stages/filters.randomize.html"
-};
+static StaticPluginInfo const s_info{
+    "filters.randomize", "Randomize points in a view.",
+    "http://pdal.io/stages/filters.randomize.html"};
 
 CREATE_STATIC_STAGE(RandomizeFilter, s_info)
 
-std::string RandomizeFilter::getName() const { return s_info.name; }
+std::string RandomizeFilter::getName() const
+{
+    return s_info.name;
+}
 
-} // namespace pdal
+void RandomizeFilter::addArgs(ProgramArgs& args)
+{
+    m_seedArg = &args.add("seed", "Random number generator seed", m_seed, 0u);
+}
 
+} // namespace pdal

filters/RandomizeFilter.hpp

@@ -1,59 +1,75 @@
 /******************************************************************************
-* Copyright (c) 2015, Hobu Inc. (hobu@hobu.co)
-*
-* All rights reserved.
-*
-* Redistribution and use in source and binary forms, with or without
-* modification, are permitted provided that the following
-* conditions are met:
-*
-*     * Redistributions of source code must retain the above copyright
-*       notice, this list of conditions and the following disclaimer.
-*     * Redistributions in binary form must reproduce the above copyright
-*       notice, this list of conditions and the following disclaimer in
-*       the documentation and/or other materials provided
-*       with the distribution.
-*     * Neither the name of Hobu, Inc. or Flaxen Geo Consulting nor the
-*       names of its contributors may be used to endorse or promote
-*       products derived from this software without specific prior
-*       written permission.
-*
-* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
-* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
-* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
-* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
-* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
-* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
-* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
-* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
-* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
-* OF SUCH DAMAGE.
-****************************************************************************/
+ * Copyright (c) 2015, Hobu Inc. (hobu@hobu.co)
+ * Copyright (c) 2019, Bradley J Chambers (brad.chambers@gmail.com)
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following
+ * conditions are met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in
+ *       the documentation and/or other materials provided
+ *       with the distribution.
+ *     * Neither the name of Hobu, Inc. or Flaxen Geo Consulting nor the
+ *       names of its contributors may be used to endorse or promote
+ *       products derived from this software without specific prior
+ *       written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ ****************************************************************************/
 
 #pragma once
 
 #include <pdal/Filter.hpp>
 #include <pdal/PointViewIter.hpp>
 
+#include <random>
+
 namespace pdal
 {
 
 class PDAL_DLL RandomizeFilter : public Filter
 {
 public:
     RandomizeFilter()
-    {}
+    {
+    }
 
     std::string getName() const;
 
 private:
+    Arg* m_seedArg;
+    unsigned m_seed;
+
+    virtual void addArgs(ProgramArgs& args);
     virtual void filter(PointView& view)
-        { std::random_shuffle(view.begin(), view.end()); }
+    {
+        if (!m_seedArg->set())
+        {
+            std::random_device rng;
+            m_seed = rng();
+        }
+        std::mt19937 mt(m_seed);
+        std::shuffle(view.begin(), view.end(), mt);
+    }
 
     RandomizeFilter& operator=(const RandomizeFilter&); // not implemented
-    RandomizeFilter(const RandomizeFilter&); // not implemented
+    RandomizeFilter(const RandomizeFilter&);            // not implemented
 };
 
 } // namespace pdal

test/unit/filters/RandomizeFilterTest.cpp

@@ -1,41 +1,42 @@
 /******************************************************************************
-* Copyright (c) 2015, Hobu Inc. (hobu@hobu.co)
-*
-* All rights reserved.
-*
-* Redistribution and use in source and binary forms, with or without
-* modification, are permitted provided that the following
-* conditions are met:
-*
-*     * Redistributions of source code must retain the above copyright
-*       notice, this list of conditions and the following disclaimer.
-*     * Redistributions in binary form must reproduce the above copyright
-*       notice, this list of conditions and the following disclaimer in
-*       the documentation and/or other materials provided
-*       with the distribution.
-*     * Neither the name of Hobu, Inc. or Flaxen Geo Consulting nor the
-*       names of its contributors may be used to endorse or promote
-*       products derived from this software without specific prior
-*       written permission.
-*
-* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
-* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
-* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
-* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
-* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
-* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
-* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
-* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
-* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
-* OF SUCH DAMAGE.
-****************************************************************************/
+ * Copyright (c) 2015, Hobu Inc. (hobu@hobu.co)
+ * Copyright (c) 2019, Bradley J Chambers (brad.chambers@gmail.com)
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following
+ * conditions are met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in
+ *       the documentation and/or other materials provided
+ *       with the distribution.
+ *     * Neither the name of Hobu, Inc. or Flaxen Geo Consulting nor the
+ *       names of its contributors may be used to endorse or promote
+ *       products derived from this software without specific prior
+ *       written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ ****************************************************************************/
 
 #include <pdal/pdal_test_main.hpp>
 
-#include <io/FauxReader.hpp>
 #include <filters/RandomizeFilter.hpp>
+#include <io/FauxReader.hpp>
 
 using namespace pdal;
 
@@ -46,8 +47,8 @@ TEST(RandomizeFilterTest, simple)
     point_count_t count = 1000;
 
     Options readerOps;
-    readerOps.add("bounds", BOX3D(1, 1, 1,
-        (double)count, (double)count, (double)count));
+    readerOps.add("bounds",
+                  BOX3D(1, 1, 1, (double)count, (double)count, (double)count));
     readerOps.add("mode", "ramp");
     readerOps.add("count", count);
 
@@ -65,10 +66,123 @@ TEST(RandomizeFilterTest, simple)
     PointViewPtr v = *s.begin();
     EXPECT_EQ(v->size(), (size_t)count);
 
-/**
-    for (PointId i = 0; i < count; i++)
-        std::cerr << "X[" << i << "] = " <<
-            v->getFieldAs<double>(Dimension::Id::X, i) << "!\n";
-**/
+    /**
+        for (PointId i = 0; i < count; i++)
+            std::cerr << "X[" << i << "] = " <<
+                v->getFieldAs<double>(Dimension::Id::X, i) << "!\n";
+    **/
+}
+
+TEST(RandomizeFilterTest, seedZero)
+{
+    point_count_t count = 10;
+
+    Options readerOps;
+    readerOps.add("bounds",
+                  BOX3D(1, 1, 1, (double)count, (double)count, double(count)));
+    readerOps.add("mode", "ramp");
+    readerOps.add("count", count);
+
+    FauxReader r;
+    r.setOptions(readerOps);
+
+    Options filterOps;
+    filterOps.add("seed", 0);
+
+    RandomizeFilter f;
+    f.setInput(r);
+    f.setOptions(filterOps);
+
+    PointTable t;
+    f.prepare(t);
+    PointViewSet s = f.execute(t);
+
+    EXPECT_EQ(1u, s.size());
+    PointViewPtr v = *s.begin();
+    EXPECT_EQ((size_t)count, v->size());
+
+    std::vector<double> vals{6, 2, 1, 7, 8, 4, 10, 9, 5, 3};
+
+    for (PointId i = 0; i < count; ++i)
+    {
+        double x = v->getFieldAs<double>(Dimension::Id::X, i);
+        EXPECT_EQ(vals[i], x);
+    }
+}
+
+TEST(RandomizeFilterTest, seedOne)
+{
+    point_count_t count = 10;
+
+    Options readerOps;
+    readerOps.add("bounds",
+                  BOX3D(1, 1, 1, (double)count, (double)count, double(count)));
+    readerOps.add("mode", "ramp");
+    readerOps.add("count", count);
+
+    FauxReader r;
+    r.setOptions(readerOps);
+
+    Options filterOps;
+    filterOps.add("seed", 1);
+
+    RandomizeFilter f;
+    f.setInput(r);
+    f.setOptions(filterOps);
+
+    PointTable t;
+    f.prepare(t);
+    PointViewSet s = f.execute(t);
+
+    EXPECT_EQ(1u, s.size());
+    PointViewPtr v = *s.begin();
+    EXPECT_EQ((size_t)count, v->size());
+
+    std::vector<double> vals{6, 10, 2, 5, 8, 1, 7, 9, 4, 3};
+
+    for (PointId i = 0; i < count; ++i)
+    {
+        double x = v->getFieldAs<double>(Dimension::Id::X, i);
+        EXPECT_EQ(vals[i], x);
+    }
 }
 
+TEST(RandomizeFilterTest, unseeded)
+{
+    point_count_t count = 10;
+
+    Options readerOps;
+    readerOps.add("bounds",
+                  BOX3D(1, 1, 1, (double)count, (double)count, double(count)));
+    readerOps.add("mode", "ramp");
+    readerOps.add("count", count);
+
+    FauxReader r;
+    r.setOptions(readerOps);
+
+    RandomizeFilter f;
+    f.setInput(r);
+
+    PointTable t;
+    f.prepare(t);
+    PointViewSet s = f.execute(t);
+
+    EXPECT_EQ(1u, s.size());
+    PointViewPtr v = *s.begin();
+    EXPECT_EQ((size_t)count, v->size());
+
+    std::vector<double> vals{6, 2, 1, 7, 8, 4, 10, 9, 5, 3};
+
+    // I don't love this test. With such a small number of samples (even with a
+    // large number), there is some probability that at least one will match
+    // what we expect from seed=0. It was the best I could think of for now
+    // though. In short, some can match, but certainly not all of them should.
+    size_t numMatches(0);
+    for (PointId i = 0; i < count; ++i)
+    {
+        double x = v->getFieldAs<double>(Dimension::Id::X, i);
+        if (vals[i] == x)
+            numMatches++;
+    }
+    EXPECT_LT(numMatches, count);
+}