@Override
  public void processInstruction(
      Class<? extends MatrixValue> valueClass,
      CachedValueMap cachedValues,
      IndexedMatrixValue tempValue,
      IndexedMatrixValue zeroInput,
      int blockRowFactor,
      int blockColFactor)
      throws DMLRuntimeException {
    QuaternaryOperator qop = (QuaternaryOperator) optr;

    ArrayList<IndexedMatrixValue> blkList = cachedValues.get(_input1);
    if (blkList != null)
      for (IndexedMatrixValue imv : blkList) {
        // Step 1: prepare inputs and output
        if (imv == null) continue;
        MatrixIndexes inIx = imv.getIndexes();
        MatrixValue inVal = imv.getValue();

        // allocate space for the output value
        IndexedMatrixValue iout = null;
        if (output == _input1) iout = tempValue;
        else iout = cachedValues.holdPlace(output, valueClass);

        MatrixIndexes outIx = iout.getIndexes();
        MatrixValue outVal = iout.getValue();

        // Step 2: get remaining inputs: Wij, Ui, Vj
        MatrixValue Xij = inVal;

        // get Wij if existing (null of WeightsType.NONE or WSigmoid any type)
        IndexedMatrixValue iWij = (_input4 != -1) ? cachedValues.getFirst(_input4) : null;
        MatrixValue Wij = (iWij != null) ? iWij.getValue() : null;
        if (null == Wij && qop.hasFourInputs()) {
          MatrixBlock mb = new MatrixBlock(1, 1, false);
          String[] parts = InstructionUtils.getInstructionParts(instString);
          mb.quickSetValue(0, 0, Double.valueOf(parts[4]));
          Wij = mb;
        }

        // get Ui and Vj, potentially through distributed cache
        MatrixValue Ui =
            (!_cacheU)
                ? cachedValues.getFirst(_input2).getValue() // U
                : MRBaseForCommonInstructions.dcValues
                    .get(_input2)
                    .getDataBlock((int) inIx.getRowIndex(), 1)
                    .getValue();
        MatrixValue Vj =
            (!_cacheV)
                ? cachedValues.getFirst(_input3).getValue() // t(V)
                : MRBaseForCommonInstructions.dcValues
                    .get(_input3)
                    .getDataBlock((int) inIx.getColumnIndex(), 1)
                    .getValue();
        // handle special input case: //V through shuffle -> t(V)
        if (Ui.getNumColumns() != Vj.getNumColumns()) {
          Vj =
              LibMatrixReorg.reorg(
                  (MatrixBlock) Vj,
                  new MatrixBlock(Vj.getNumColumns(), Vj.getNumRows(), Vj.isInSparseFormat()),
                  new ReorgOperator(SwapIndex.getSwapIndexFnObject()));
        }

        // Step 3: process instruction
        Xij.quaternaryOperations(qop, Ui, Vj, Wij, outVal);

        // set output indexes

        if (qop.wtype1 != null || qop.wtype4 != null) outIx.setIndexes(1, 1); // wsloss
        else if (qop.wtype2 != null
            || qop.wtype5 != null
            || qop.wtype3 != null && qop.wtype3.isBasic())
          outIx.setIndexes(inIx); // wsigmoid/wdivmm-basic
        else { // wdivmm
          boolean left = qop.wtype3.isLeft();
          outIx.setIndexes(left ? inIx.getColumnIndex() : inIx.getRowIndex(), 1);
        }

        // put the output value in the cache
        if (iout == tempValue) cachedValues.add(output, iout);
      }
  }
 @Override
 public byte[] getAllIndexes() {
   QuaternaryOperator qop = (QuaternaryOperator) optr;
   if (qop.hasFourInputs()) return new byte[] {_input1, _input2, _input3, _input4, output};
   else return new byte[] {_input1, _input2, _input3, output};
 }