From a738a37240b13fa22aa7a3333c0a58c71759ab22 Mon Sep 17 00:00:00 2001
From: gmungoc <g.m.carstairs@dundee.ac.uk>
Date: Thu, 5 Oct 2017 15:15:41 +0100
Subject: [PATCH] JAL-2738 method to compound / traverse / convolve two
 mappings

---
 src/jalview/util/MapList.java      |   59 ++++++++++++++++++
 test/jalview/util/MapListTest.java |  118 ++++++++++++++++++++++++++++++++++++
 2 files changed, 177 insertions(+)

diff --git a/src/jalview/util/MapList.java b/src/jalview/util/MapList.java
index 4658724..3ce0bb3 100644
--- a/src/jalview/util/MapList.java
+++ b/src/jalview/util/MapList.java
@@ -1120,4 +1120,63 @@ public class MapList
             || (fromRatio == 3 && toRatio == 1);
   }
 
+  /**
+   * Returns a map which is the composite of this one and the input map. That
+   * is, the output map has the fromRanges of this map, and its toRanges are the
+   * toRanges of this map as transformed by the input map.
+   * <p>
+   * Returns null if the mappings cannot be traversed (not all toRanges of this
+   * map correspond to fromRanges of the input), or if this.toRatio does not
+   * match map.fromRatio.
+   * 
+   * <pre>
+   * Example 1:
+   *    this:   from [1-100] to [501-600]
+   *    input:  from [10-40] to [60-90]
+   *    output: from [10-40] to [560-590]
+   * Example 2 ('reverse strand exons'):
+   *    this:   from [1-100] to [2000-1951], [1000-951] // transcript to loci
+   *    input:  from [1-50]  to [41-90] // CDS to transcript
+   *    output: from [10-40] to [1960-1951], [1000-971] // CDS to gene loci
+   * </pre>
+   * 
+   * @param map
+   * @return
+   */
+  public MapList traverse(MapList map)
+  {
+    if (map == null)
+    {
+      return null;
+    }
+
+    /*
+     * compound the ratios by this rule:
+     * A:B with M:N gives A*M:B*N
+     * reduced by greatest common divisor
+     * so 1:3 with 3:3 is 3:9 or 1:3
+     * 1:3 with 3:1 is 3:3 or 1:1
+     * 1:3 with 1:3 is 1:9
+     * 2:5 with 3:7 is 6:35
+     */
+    int outFromRatio = getFromRatio() * map.getFromRatio();
+    int outToRatio = getToRatio() * map.getToRatio();
+    int gcd = MathUtils.gcd(outFromRatio, outToRatio);
+    outFromRatio /= gcd;
+    outToRatio /= gcd;
+
+    List<int[]> toRanges = new ArrayList<>();
+    for (int[] range : getToRanges())
+    {
+      int[] transferred = map.locateInTo(range[0], range[1]);
+      if (transferred == null)
+      {
+        return null;
+      }
+      toRanges.add(transferred);
+    }
+
+    return new MapList(getFromRanges(), toRanges, outFromRatio, outToRatio);
+  }
+
 }
diff --git a/test/jalview/util/MapListTest.java b/test/jalview/util/MapListTest.java
index a2f38e2..f3395ca 100644
--- a/test/jalview/util/MapListTest.java
+++ b/test/jalview/util/MapListTest.java
@@ -814,4 +814,122 @@ public class MapListTest
     assertEquals(1, merged.size());
     assertArrayEquals(new int[] { 9, 0 }, merged.get(0));
   }
+
+  /**
+   * Test the method that compounds ('traverses') two mappings
+   */
+  @Test
+  public void testTraverse()
+  {
+    /*
+     * simple 1:1 plus 1:1 forwards
+     */
+    MapList ml1 = new MapList(new int[] { 3, 4, 8, 12 }, new int[] { 5, 8,
+        11, 13 }, 1, 1);
+    MapList ml2 = new MapList(new int[] { 1, 50 }, new int[] { 40, 45, 70,
+        75, 90, 127 }, 1, 1);
+    MapList compound = ml1.traverse(ml2);
+
+    assertEquals(compound.getFromRatio(), 1);
+    assertEquals(compound.getToRatio(), 1);
+    List<int[]> fromRanges = compound.getFromRanges();
+    assertEquals(fromRanges.size(), 2);
+    assertArrayEquals(new int[] { 3, 4 }, fromRanges.get(0));
+    assertArrayEquals(new int[] { 8, 12 }, fromRanges.get(1));
+    List<int[]> toRanges = compound.getToRanges();
+    assertEquals(toRanges.size(), 2);
+    // 5-8 maps to 44-45,70-71
+    // 11-13 maps to 74-75,90
+    assertArrayEquals(new int[] { 44, 45, 70, 71 }, toRanges.get(0));
+    assertArrayEquals(new int[] { 74, 75, 90, 90 }, toRanges.get(1));
+
+    /*
+     * 1:1 over 1:1 backwards ('reverse strand')
+     */
+    ml1 = new MapList(new int[] { 1, 50 }, new int[] { 70, 119 }, 1, 1);
+    ml2 = new MapList(new int[] { 1, 500 },
+            new int[] { 1000, 901, 600, 201 }, 1, 1);
+    compound = ml1.traverse(ml2);
+
+    assertEquals(compound.getFromRatio(), 1);
+    assertEquals(compound.getToRatio(), 1);
+    fromRanges = compound.getFromRanges();
+    assertEquals(fromRanges.size(), 1);
+    assertArrayEquals(new int[] { 1, 50 }, fromRanges.get(0));
+    toRanges = compound.getToRanges();
+    assertEquals(toRanges.size(), 1);
+    assertArrayEquals(new int[] { 931, 901, 600, 582 }, toRanges.get(0));
+
+    /*
+     * 1:1 plus 1:3 should result in 1:3
+     */
+    ml1 = new MapList(new int[] { 1, 30 }, new int[] { 11, 40 }, 1, 1);
+    ml2 = new MapList(new int[] { 1, 100 }, new int[] { 1, 50, 91, 340 },
+            1, 3);
+    compound = ml1.traverse(ml2);
+
+    assertEquals(compound.getFromRatio(), 1);
+    assertEquals(compound.getToRatio(), 3);
+    fromRanges = compound.getFromRanges();
+    assertEquals(fromRanges.size(), 1);
+    assertArrayEquals(new int[] { 1, 30 }, fromRanges.get(0));
+    // 11-40 maps to 31-50,91-160
+    toRanges = compound.getToRanges();
+    assertEquals(toRanges.size(), 1);
+    assertArrayEquals(new int[] { 31, 50, 91, 160 }, toRanges.get(0));
+
+    /*
+     * 3:1 plus 1:1 should result in 3:1
+     */
+    ml1 = new MapList(new int[] { 1, 30 }, new int[] { 11, 20 }, 3, 1);
+    ml2 = new MapList(new int[] { 1, 100 }, new int[] { 1, 15, 91, 175 },
+            1, 1);
+    compound = ml1.traverse(ml2);
+
+    assertEquals(compound.getFromRatio(), 3);
+    assertEquals(compound.getToRatio(), 1);
+    fromRanges = compound.getFromRanges();
+    assertEquals(fromRanges.size(), 1);
+    assertArrayEquals(new int[] { 1, 30 }, fromRanges.get(0));
+    // 11-20 maps to 11-15, 91-95
+    toRanges = compound.getToRanges();
+    assertEquals(toRanges.size(), 1);
+    assertArrayEquals(new int[] { 11, 15, 91, 95 }, toRanges.get(0));
+
+    /*
+     * 1:3 plus 3:1 should result in 1:1
+     */
+    ml1 = new MapList(new int[] { 21, 40 }, new int[] { 13, 72 }, 1, 3);
+    ml2 = new MapList(new int[] { 1, 300 }, new int[] { 51, 70, 121, 200 },
+            3, 1);
+    compound = ml1.traverse(ml2);
+
+    assertEquals(compound.getFromRatio(), 1);
+    assertEquals(compound.getToRatio(), 1);
+    fromRanges = compound.getFromRanges();
+    assertEquals(fromRanges.size(), 1);
+    assertArrayEquals(new int[] { 21, 40 }, fromRanges.get(0));
+    // 13-72 maps 3:1 to 55-70, 121-124
+    toRanges = compound.getToRanges();
+    assertEquals(toRanges.size(), 1);
+    assertArrayEquals(new int[] { 55, 70, 121, 124 }, toRanges.get(0));
+
+    /*
+     * 3:1 plus 1:3 should result in 1:1
+     */
+    ml1 = new MapList(new int[] { 31, 90 }, new int[] { 13, 32 }, 3, 1);
+    ml2 = new MapList(new int[] { 11, 40 }, new int[] { 41, 50, 71, 150 },
+            1, 3);
+    compound = ml1.traverse(ml2);
+
+    assertEquals(compound.getFromRatio(), 1);
+    assertEquals(compound.getToRatio(), 1);
+    fromRanges = compound.getFromRanges();
+    assertEquals(fromRanges.size(), 1);
+    assertArrayEquals(new int[] { 31, 90 }, fromRanges.get(0));
+    // 13-32 maps to 47-50,71-126
+    toRanges = compound.getToRanges();
+    assertEquals(toRanges.size(), 1);
+    assertArrayEquals(new int[] { 47, 50, 71, 126 }, toRanges.get(0));
+  }
 }
-- 
1.7.10.2