Chi.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to you under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.calcite.rel.stream;

import org.apache.calcite.plan.RelOptCluster;
import org.apache.calcite.plan.RelTraitSet;
import org.apache.calcite.rel.RelNode;
import org.apache.calcite.rel.SingleRel;

/**
 * Relational operator that converts a stream to a relation.
 *
 * <p>Chi is named for the Greek letter &chi; and pronounced 'kai'.
 *
 * <p>Chi is the inverse of {@link Delta}. For any relation {@code R},
 * Chi(Delta(R)) == R.
 */
public class Chi extends SingleRel {
  protected Chi(RelOptCluster cluster, RelTraitSet traits, RelNode input) {
    super(cluster, traits, input);
  }
}