alpass163gmail commented on code in PR #18539:
URL: https://github.com/apache/iotdb/pull/18539#discussion_r3910203743
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iotdb-core/node-commons/src/main/java/org/apache/iotdb/commons/udf/builtin/relational/tvf/XCorrTableFunction.java:
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@@ -0,0 +1,229 @@
+package org.apache.iotdb.commons.udf.builtin.relational.tvf;
+
+import org.apache.iotdb.commons.exception.SemanticException;
+import org.apache.iotdb.commons.i18n.CommonMessages;
+import org.apache.iotdb.udf.api.exception.UDFException;
+import org.apache.iotdb.udf.api.relational.TableFunction;
+import org.apache.iotdb.udf.api.relational.access.Record;
+import org.apache.iotdb.udf.api.relational.table.MapTableFunctionHandle;
+import org.apache.iotdb.udf.api.relational.table.TableFunctionAnalysis;
+import org.apache.iotdb.udf.api.relational.table.TableFunctionHandle;
+import
org.apache.iotdb.udf.api.relational.table.TableFunctionProcessorProvider;
+import org.apache.iotdb.udf.api.relational.table.argument.Argument;
+import org.apache.iotdb.udf.api.relational.table.argument.DescribedSchema;
+import org.apache.iotdb.udf.api.relational.table.argument.TableArgument;
+import
org.apache.iotdb.udf.api.relational.table.processor.TableFunctionDataProcessor;
+import
org.apache.iotdb.udf.api.relational.table.specification.ParameterSpecification;
+import
org.apache.iotdb.udf.api.relational.table.specification.ScalarParameterSpecification;
+import
org.apache.iotdb.udf.api.relational.table.specification.TableParameterSpecification;
+import org.apache.iotdb.udf.api.type.Type;
+
+import org.apache.tsfile.block.column.ColumnBuilder;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+import static
org.apache.iotdb.commons.udf.builtin.relational.tvf.FilterTransferTableFunction.FilterTransferDataProcessor.MAX_COUNT_IN_ONE_PARTITION;
+
+public class XCorrTableFunction implements TableFunction {
+
+ public static final String DATA_PARAMETER_NAME = "DATA";
+ public static final String TIMECOL_PARAMETER_NAME = "TIMECOL";
+ private static final String PARTITION_TYPES_PROPERTY = "PARTITION_TYPES";
+
+ @Override
+ public List<ParameterSpecification> getArgumentsSpecifications() {
+ return Arrays.asList(
+
TableParameterSpecification.builder().name(DATA_PARAMETER_NAME).setSemantics().build(),
+ ScalarParameterSpecification.builder()
+ .name(TIMECOL_PARAMETER_NAME)
+ .type(Type.STRING)
+ .build());
+ }
+
+ @Override
+ public TableFunctionAnalysis analyze(Map<String, Argument> arguments) throws
UDFException {
+ // order by column must only be the time column
+ int timeColumnIndex =
+ WindowTVFUtils.checkOrderByColumn(arguments, DATA_PARAMETER_NAME,
TIMECOL_PARAMETER_NAME);
+ TableArgument tableArgument = (TableArgument)
arguments.get(DATA_PARAMETER_NAME);
+
+ List<Integer> partitionIndexes =
WindowTVFUtils.getPartitionIndexes(tableArgument);
+ Set<Integer> excludedIndexes = new HashSet<>(partitionIndexes);
+ excludedIndexes.add(timeColumnIndex);
+
+ List<Type> partitionTypes = new ArrayList<>();
+ DescribedSchema.Builder schemaBuilder = new DescribedSchema.Builder();
+
+ // record the partition columns
+ for (int partitionIndex : partitionIndexes) {
+ Type partitionType = tableArgument.getFieldTypes().get(partitionIndex);
+ partitionTypes.add(partitionType);
+ schemaBuilder.addField(
+ tableArgument.getFieldNames().get(partitionIndex).get(),
partitionType);
+ }
+
+ List<Integer> calculationIndexes =
+ new ArrayList<>(WindowTVFUtils.getCalculationIndexes(tableArgument,
excludedIndexes, null));
+
+ if (calculationIndexes.size() != 2) {
+ throw new SemanticException(
+ String.format(
+ CommonMessages
+
.EXCEPTION_XCORR_REQUIRES_EXACTLY_TWO_CALCULATION_COLUMNS_BUT_FOUND_ARG_2FF8EB0C,
+ calculationIndexes.size()));
+ }
+
+ // XCorr emits one correlation value per lag; the original time column is
used for ordering
+ // only and is not part of the result schema.
+ String firstColumnName =
tableArgument.getFieldNames().get(calculationIndexes.get(0)).get();
+ String secondColumnName =
tableArgument.getFieldNames().get(calculationIndexes.get(1)).get();
+ schemaBuilder.addField(
+ String.format("xcorr(%s, %s)", firstColumnName, secondColumnName),
Type.DOUBLE);
Review Comment:
do not need emit the lag column
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