Add source file for rf_exp functions

Author: vpipkt

core/src/main/scala/astraea/spark/rasterframes/expressions/localops/Exp.scala

@@ -0,0 +1,116 @@
+/*
+ * This software is licensed under the Apache 2 license, quoted below.
+ *
+ * Copyright 2019 Astraea, Inc.
+ *
+ * Licensed 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.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ */
+
+package astraea.spark.rasterframes.expressions.localops
+
+import astraea.spark.rasterframes._
+import astraea.spark.rasterframes.expressions.{UnaryLocalRasterOp, fpTile}
+import geotrellis.raster.Tile
+import org.apache.spark.sql.catalyst.expressions.{Expression, ExpressionDescription}
+import org.apache.spark.sql.catalyst.expressions.codegen.CodegenFallback
+import org.apache.spark.sql.types.DataType
+import org.apache.spark.sql.{Column, TypedColumn}
+
+
+@ExpressionDescription(
+  usage = "_FUNC_(tile) - Performs cell-wise exponential.",
+  arguments = """
+  Arguments:
+    * tile - input tile""",
+  examples = """
+  Examples:
+    > SELECT _FUNC_(tile);
+       ..."""
+)
+case class Exp(child: Expression) extends UnaryLocalRasterOp with CodegenFallback {
+  override val nodeName: String = "exp"
+
+  override protected def op(tile: Tile): Tile = fpTile(tile).localPowValue(math.E)
+
+  override def dataType: DataType = child.dataType
+}
+object Exp {
+  def apply(tile: Column): TypedColumn[Any, Tile] =
+    new Column(Exp(tile.expr)).as[Tile]
+}
+
+@ExpressionDescription(
+  usage = "_FUNC_(tile) - Compute 10 to the power of cell values.",
+  arguments = """
+  Arguments:
+    * tile - input tile""",
+  examples = """
+  Examples:
+    > SELECT _FUNC_(tile);
+       ..."""
+)
+case class Exp10(child: Expression) extends UnaryLocalRasterOp with CodegenFallback {
+  override val nodeName: String = "log10"
+
+  override protected def op(tile: Tile): Tile = fpTile(tile).localPowValue(10.0)
+
+  override def dataType: DataType = child.dataType
+}
+object Exp10 {
+  def apply(tile: Column): TypedColumn[Any, Tile] = new Column(Exp10(tile.expr)).as[Tile]
+}
+
+@ExpressionDescription(
+  usage = "_FUNC_(tile) - Compute 2 to the power of cell values.",
+  arguments = """
+  Arguments:
+    * tile - input tile""",
+  examples = """
+  Examples:
+    > SELECT _FUNC_(tile);
+       ..."""
+)
+case class Exp2(child: Expression) extends UnaryLocalRasterOp with CodegenFallback {
+  override val nodeName: String = "exp2"
+
+  override protected def op(tile: Tile): Tile = fpTile(tile).localPowValue(2.0)
+
+  override def dataType: DataType = child.dataType
+}
+object Exp2{
+  def apply(tile: Column): TypedColumn[Any, Tile] = new Column(Exp2(tile.expr)).as[Tile]
+}
+
+@ExpressionDescription(
+  usage = "_FUNC_(tile) - Performs cell-wise exponential, then subtract one.",
+  arguments = """
+  Arguments:
+    * tile - input tile""",
+  examples = """
+  Examples:
+    > SELECT _FUNC_(tile);
+       ..."""
+)
+case class ExpM1(child: Expression) extends UnaryLocalRasterOp with CodegenFallback {
+  override val nodeName: String = "expm1"
+
+  override protected def op(tile: Tile): Tile = fpTile(tile).localPowValue(math.E).localSubtract(1.0)
+
+  override def dataType: DataType = child.dataType
+}
+object ExpM1{
+  def apply(tile: Column): TypedColumn[Any, Tile] = new Column(ExpM1(tile.expr)).as[Tile]
+}