Small fixes

Signed-off-by: Ryan Nett <rnett@calpoly.edu>

Author: rnett

tensorflow-core/tensorflow-core-api/src/main/java/org/tensorflow/Graph.java

@@ -33,7 +33,6 @@
 import java.util.Collections;
 import java.util.Iterator;
 import java.util.LinkedHashSet;
-import java.util.LinkedList;
 import java.util.List;
 import java.util.Queue;
 import java.util.Set;
@@ -182,11 +181,7 @@ public Output<?> output(String output) {
       }
       return new Output(operation, index);
     } catch (NumberFormatException e) {
-      GraphOperation op = operation(output);
-      if (op == null) {
-        return null;
-      }
-      return new Output(op, 0);
+      throw new IllegalArgumentException("Could not get output for badly formatted output name: \"" + output + "\"", e);
     }
   }
 
@@ -343,7 +338,7 @@ public synchronized Set<GraphOperation> completeSubgraph(Set<Operand<?>> inputs,
    * @param outputs the starting points of the traversal.
    * @return the ops needed to calculate {@code outputs}, not including {@code outputs}
    */
-  public Set<GraphOperation> upstreamOps(Set<GraphOperation> outputs) {
+  public Set<GraphOperation> subgraphToOps(Set<GraphOperation> outputs) {
     Set<GraphOperation> seen = new LinkedHashSet<>(outputs.size());
     Queue<GraphOperation> todo = new ArrayDeque<>(outputs);
     while (!todo.isEmpty()) {
@@ -365,7 +360,7 @@ public Set<GraphOperation> upstreamOps(Set<GraphOperation> outputs) {
    * @param inputs the starting points of the traversal.
    * @return the ops that depend on {@code inputs}, not including {@code inputs}
    */
-  public synchronized Set<GraphOperation> downstreamOps(Set<GraphOperation> inputs) {
+  public synchronized Set<GraphOperation> subgraphFromOps(Set<GraphOperation> inputs) {
     Set<GraphOperation> seen = new LinkedHashSet<>(inputs.size());
     Queue<GraphOperation> todo = new ArrayDeque<>(inputs);
     while (!todo.isEmpty()) {
@@ -387,8 +382,8 @@ public synchronized Set<GraphOperation> downstreamOps(Set<GraphOperation> inputs
    * @param outputs the starting points of the traversal.
    * @return the ops needed to calculate {@code outputs}, not including {@code outputs}
    */
-  public Set<GraphOperation> upstream(Set<Operand<?>> outputs) {
-    return upstreamOps(outputs.stream().map(this::graphOp).collect(Collectors.toSet()));
+  public Set<GraphOperation> subgraphTo(Set<Operand<?>> outputs) {
+    return subgraphToOps(outputs.stream().map(this::graphOp).collect(Collectors.toSet()));
   }
 
   /**
@@ -398,14 +393,14 @@ public Set<GraphOperation> upstream(Set<Operand<?>> outputs) {
    * @param inputs the starting points of the traversal.
    * @return the ops that depend on {@code inputs}, not including {@code inputs}
    */
-  public synchronized Set<GraphOperation> downstream(Set<Operand<?>> inputs) {
+  public synchronized Set<GraphOperation> subgraphFrom(Set<Operand<?>> inputs) {
     Set<GraphOperation> ops = new LinkedHashSet<>();
     for (Operand<?> input : inputs) {
       GraphOperation op = graphOp(input);
       ops.addAll(op.consumers(input.asOutput().index()));
       ops.addAll(op.controlConsumers());
     }
-    Set<GraphOperation> downstream = downstreamOps(ops);
+    Set<GraphOperation> downstream = subgraphFromOps(ops);
     downstream.addAll(ops);
     return downstream;
   }

tensorflow-core/tensorflow-core-api/src/main/java/org/tensorflow/GraphOperation.java

@@ -188,9 +188,7 @@ Tensor tensor(int outputIdx) {
    * Get the number of inputs to the op, not including control inputs.
    */
   public int numInputs() {
-    try (PointerScope scope = new PointerScope()) {
-      return TF_OperationNumInputs(getUnsafeNativeHandle());
-    }
+    return TF_OperationNumInputs(getUnsafeNativeHandle());
   }
 
   /**