Add downsampling arguments to Mutect

- maxReadsInRegionPErSample, minReadsPerAlignment start are now M2 args
	- maxReadsInMemoryPerSample is an activeRegionWalker arg

protected/gatk-tools-protected/src/main/java/org/broadinstitute/gatk/tools/walkers/cancer/m2/MuTect2.java

@@ -200,8 +200,6 @@ public class MuTect2 extends ActiveRegionWalker<List<VariantContext>, Integer> i
     private double log10GlobalReadMismappingRate;
     private static final int REFERENCE_PADDING = 500;
     private static final byte MIN_TAIL_QUALITY_WITH_ERROR_CORRECTION = 6;
-    private final static int maxReadsInRegionPerSample = 1000; // TODO -- should be an argument
-    private final static int minReadsPerAlignmentStart = 5; // TODO -- should be an argument
 
     @ArgumentCollection
     protected M2ArgumentCollection MTAC = new M2ArgumentCollection();
@@ -293,6 +291,16 @@ public class MuTect2 extends ActiveRegionWalker<List<VariantContext>, Integer> i
     @Argument(fullName="doNotRunPhysicalPhasing", shortName="doNotRunPhysicalPhasing", doc="Disable physical phasing", required = false)
     protected boolean doNotRunPhysicalPhasing = false;
 
+    /**
+     * When downsampling, level the coverage of the reads in each sample to no more than maxReadsInRegionPerSample reads,
+     * not reducing coverage at any read start to less than minReadsPerAlignmentStart
+     */
+    @Argument(fullName = "maxReadsInRegionPerSample", shortName = "maxReadsInRegionPerSample", doc="Maximum reads in an active region", required = false)
+    protected int maxReadsInRegionPerSample = 1000;
+
+    @Argument(fullName = "minReadsPerAlignmentStart", shortName = "minReadsPerAlignStart", doc="Minimum number of reads sharing the same alignment start for each genomic location in an active region", required = false)
+    protected int minReadsPerAlignmentStart = 5;
+
     public RodBinding<VariantContext> getDbsnpRodBinding() { return MTAC.dbsnp.dbsnp; }
 
     @Override

public/gatk-engine/src/main/java/org/broadinstitute/gatk/engine/traversals/TraverseActiveRegions.java

@@ -162,8 +162,8 @@ public final class TraverseActiveRegions<M, T> extends TraversalEngine<M,T,Activ
         activityProfile = new BandPassActivityProfile(engine.getGenomeLocParser(), engine.getIntervals(), this.walker.maxProbPropagationDistance, this.walker.activeProbThreshold,
                 BandPassActivityProfile.MAX_FILTER_SIZE, bandPassSigma);
 
-        final int maxReadsAcrossSamples = annotation.maxReadsToHoldInMemoryPerSample() * ReadUtils.getSAMFileSamples(engine.getSAMFileHeader()).size();
-        final int maxReadsToHoldInMemory = Math.min(maxReadsAcrossSamples, annotation.maxReadsToHoldTotal());
+        final int maxReadsAcrossSamples = this.walker.maxReadsInMemoryPerSample * ReadUtils.getSAMFileSamples(engine.getSAMFileHeader()).size();
+        final int maxReadsToHoldInMemory = Math.min(maxReadsAcrossSamples, this.walker.maxTotalReadsInMemory);
         myReads = new TAROrderedReadCache(maxReadsToHoldInMemory);
     }
 

public/gatk-engine/src/main/java/org/broadinstitute/gatk/engine/walkers/ActiveRegionTraversalParameters.java

@@ -78,20 +78,4 @@ public @interface ActiveRegionTraversalParameters {
      * @return the breadth of the band pass gaussian kernel we want for our traversal
      */
     public double bandPassSigma() default BandPassActivityProfile.DEFAULT_SIGMA;
-
-    /**
-     * What is the maximum number of reads we're willing to hold in memory per sample
-     * during the traversal?  This limits our exposure to unusually large amounts
-     * of coverage in the engine.
-     * @return the maximum number of reads we're willing to hold in memory
-     */
-    public int maxReadsToHoldInMemoryPerSample() default 30000;
-
-    /**
-     * No matter what the per sample value says, we will never hold more than this
-     * number of reads in memory at any time.  Provides an upper bound on the total number
-     * of reads in the case where we have a lot of samples.
-     * @return the maximum number of reads to hold in memory
-     */
-    public int maxReadsToHoldTotal() default 10000000;
 }

public/gatk-engine/src/main/java/org/broadinstitute/gatk/engine/walkers/ActiveRegionWalker.java

@@ -108,6 +108,24 @@ public abstract class ActiveRegionWalker<MapType, ReduceType> extends Walker<Map
     @Argument(fullName="bandPassSigma", shortName="bandPassSigma", doc="The sigma of the band pass filter Gaussian kernel; if not provided defaults to Walker annotated default", required = false)
     public Double bandPassSigma = null;
 
+    /**
+     * What is the maximum number of reads we're willing to hold in memory per sample
+     * during the traversal?  This limits our exposure to unusually large amounts
+     * of coverage in the engine.
+     */
+    @Advanced
+    @Argument(fullName="maxReadsInMemoryPerSample", shortName="maxReadsInMemoryPerSample", doc="Maximum reads per sample given to traversal map() function", required = false)
+    public int maxReadsInMemoryPerSample = 30000;
+
+    /**
+     * What is the maximum number of reads we're willing to hold in memory per sample
+     * during the traversal?  This limits our exposure to unusually large amounts
+     * of coverage in the engine.
+     */
+    @Advanced
+    @Argument(fullName="maxTotalReadsInMemory", shortName="maxTotalReadsInMemory", doc="Maximum total reads given to traversal map() function", required = false)
+    public int maxTotalReadsInMemory = 10000000;
+
     /*
      * For active region limits in ActivityProfile
 *   */