Added walker to print out a histogram of where mismatches occur in alignments

git-svn-id: file:///humgen/gsa-scr1/gsa-engineering/svn_contents/trunk@89 348d0f76-0448-11de-a6fe-93d51630548a

playground/java/src/org/broadinstitute/sting/gatk/walkers/AlignedReadsHistoWalker.java

@@ -19,8 +19,8 @@ public class AlignedReadsHistoWalker extends BasicReadWalker<Integer, Integer> {
     }
 
     public void initialize() {
-        for ( int i = 0; i < this.alignCounts.length; i++ ) {
+        for ( int i = 0; i < alignCounts.length; i++ ) {
-            this.alignCounts[i] = 0;
+            alignCounts[i] = 0;
         }
     }
 
@@ -36,7 +36,8 @@ public class AlignedReadsHistoWalker extends BasicReadWalker<Integer, Integer> {
     public Integer map(LocusContext context, SAMRecord read) {
         //System.out.println(read.getAttribute("NM"));
         int editDist = Integer.parseInt(read.getAttribute("NM").toString());
-        this.alignCounts[editDist]++;
+        if (editDist <= 50)
+            alignCounts[editDist]++;
         return 1;
     }
 
@@ -48,7 +49,7 @@ public class AlignedReadsHistoWalker extends BasicReadWalker<Integer, Integer> {
 
     public void onTraversalDone() {
         int curTotal = 0;
-        for ( int i = 0; i < this.alignCounts.length; i++ ) {
+        for ( int i = 0; i < alignCounts.length; i++ ) {
             curTotal += alignCounts[i];
             System.out.printf("%3d %10d%n", i, curTotal);
         }

playground/java/src/org/broadinstitute/sting/gatk/walkers/MismatchHistoWalker.java

@@ -0,0 +1,87 @@
+package org.broadinstitute.sting.gatk.walkers;
+
+import net.sf.samtools.SAMRecord;
+import org.broadinstitute.sting.gatk.LocusContext;
+import org.broadinstitute.sting.utils.Utils;
+import edu.mit.broad.picard.reference.ReferenceSequence;
+
+import java.util.Iterator;
+import java.util.List;
+import static java.lang.reflect.Array.*;
+
+public class MismatchHistoWalker extends BasicReadWalker<Integer, Integer> {
+
+    protected long[] mismatchCounts = new long[0];
+    protected final int MIN_TARGET_EDIT_DISTANCE = 5;
+    protected final int MAX_TARGET_EDIT_DISTANCE = 10;
+
+    public String getName() {
+        return "Mismatch_Histogram";
+    }
+
+    // Do we actually want to operate on the context?
+    public boolean filter(LocusContext context, SAMRecord read) {
+	    // we only want aligned reads
+	    return !read.getReadUnmappedFlag();
+    }
+
+    public Integer map(LocusContext context, SAMRecord read) {
+
+        int editDist = Integer.parseInt(read.getAttribute("NM").toString());
+
+        // ignore alignments with indels for now
+        if ( read.getAlignmentBlocks().size() == 1 &&
+             editDist >= MIN_TARGET_EDIT_DISTANCE &&
+             editDist <= MAX_TARGET_EDIT_DISTANCE ) {
+
+            ReferenceSequence refseq = context.getReferenceContig();
+
+            int start = read.getAlignmentStart()-1;
+            int stop  = read.getAlignmentEnd();
+
+            List<Byte> refSeq = Utils.subseq(context.getReferenceContig().getBases(), start, stop);
+            List<Byte> readBases = Utils.subseq(read.getReadBases());
+
+            assert(refSeq.size() == readBases.size());
+
+            // it's actually faster to reallocate a resized array than to use ArrayLists...
+            if ( refSeq.size() > mismatchCounts.length ) {
+                int oldLength = mismatchCounts.length;
+                mismatchCounts = (long[])resizeArray(mismatchCounts, refSeq.size());
+                for ( int i = oldLength; i < refSeq.size(); i++ )
+                    mismatchCounts[i] = 0;
+            }
+
+            String refStr = Utils.baseList2string(refSeq).toUpperCase();
+            String readStr = Utils.baseList2string(readBases).toUpperCase();
+            for ( int i = 0; i < refStr.length(); i++) {
+                if ( refStr.charAt(i) != readStr.charAt(i) )
+                    mismatchCounts[i]++;
+            }
+        }
+
+        return 1;
+    }
+
+    public Integer reduceInit() { return 0; }
+
+    public Integer reduce(Integer value, Integer sum) {
+        return value + sum;
+    }
+
+    public void onTraversalDone() {
+        for ( int i = 0; i < mismatchCounts.length; i++ ) {
+            System.out.printf("%3d %10d%n", (i+1), mismatchCounts[i]);
+        }
+    }
+
+    private static Object resizeArray (Object oldArray, int newSize) {
+        int oldSize = getLength(oldArray);
+        Class elementType = oldArray.getClass().getComponentType();
+        Object newArray = newInstance(elementType,newSize);
+        int preserveLength = Math.min(oldSize,newSize);
+        if (preserveLength > 0)
+            System.arraycopy (oldArray,0,newArray,0,preserveLength);
+        return newArray;
+    }
+}