dtenedor commented on code in PR #48004:
URL: https://github.com/apache/spark/pull/48004#discussion_r1758115572
##########
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/randomExpressions.scala:
##########
@@ -181,3 +187,239 @@ case class Randn(child: Expression, hideSeed: Boolean =
false) extends RDG {
object Randn {
def apply(seed: Long): Randn = Randn(Literal(seed, LongType))
}
+
+@ExpressionDescription(
+ usage = """
+ _FUNC_(min, max[, seed]) - Returns a random value with independent and
identically
+ distributed (i.i.d.) values with the specified range of numbers. The
random seed is optional.
+ The provided numbers specifying the minimum and maximum values of the
range must be constant.
+ If both of these numbers are integers, then the result will also be an
integer. Otherwise if
+ one or both of these are floating-point numbers, then the result will
also be a floating-point
+ number.
+ """,
+ examples = """
+ Examples:
+ > SELECT _FUNC_(10, 20) > 0 AS result;
+ true
+ """,
+ since = "4.0.0",
+ group = "math_funcs")
+object UniformExpressionBuilder extends ExpressionBuilder {
+ override def build(funcName: String, expressions: Seq[Expression]):
Expression = {
+ val numArgs = expressions.length
+ expressions match {
+ case Seq(min, max) =>
+ Uniform(min, max)
+ case Seq(min, max, seed) =>
+ Uniform(min, max, seed)
+ case _ =>
+ throw QueryCompilationErrors.wrongNumArgsError(funcName, Seq(2, 3),
numArgs)
+ }
+ }
+}
+
+case class Uniform(min: Expression, max: Expression)
+ extends RuntimeReplaceable with BinaryLike[Expression] with
ExpressionWithRandomSeed {
+
+ private var seed: Expression = Literal(Uniform.random.nextLong(), LongType)
+ final override lazy val deterministic: Boolean = false
+ override val nodePatterns: Seq[TreePattern] =
+ Seq(RUNTIME_REPLACEABLE, EXPRESSION_WITH_RANDOM_SEED)
+
+ override val dataType: DataType = {
+ val first = min.dataType
+ val second = max.dataType
+ (min.dataType, max.dataType) match {
+ case _ if !valid(min) || !valid(max) => NullType
+ case (_, LongType) | (LongType, _) if Seq(first, second).forall(integer)
=> LongType
+ case (_, IntegerType) | (IntegerType, _) if Seq(first,
second).forall(integer) => IntegerType
+ case (_, ShortType) | (ShortType, _) if Seq(first,
second).forall(integer) => ShortType
+ case (_, DoubleType) | (DoubleType, _) => DoubleType
+ case (_, FloatType) | (FloatType, _) => FloatType
+ case _ => NullType
+ }
+ }
+
+ private def valid(e: Expression): Boolean = e.dataType match {
+ case _: ShortType | _: IntegerType | _: LongType | _: FloatType | _:
DoubleType => true
+ case _ => false
+ }
+
+ private def integer(t: DataType): Boolean = t match {
+ case _: ShortType | _: IntegerType | _: LongType => true
+ case _ => false
+ }
+
+ override def checkInputDataTypes(): TypeCheckResult = {
+ var result: TypeCheckResult = TypeCheckResult.TypeCheckSuccess
+ def requiredType = "integer or floating-point"
+ Seq((min, "min", 0),
+ (max, "max", 1),
+ (seed, "seed", 2)).foreach {
+ case (expr: Expression, name: String, index: Int) =>
+ if (!expr.foldable && result == TypeCheckResult.TypeCheckSuccess) {
+ result = DataTypeMismatch(
+ errorSubClass = "NON_FOLDABLE_INPUT",
+ messageParameters = Map(
+ "inputName" -> name,
+ "inputType" -> requiredType,
+ "inputExpr" -> toSQLExpr(expr)))
+ } else if (!valid(expr) && result == TypeCheckResult.TypeCheckSuccess)
{
+ result = DataTypeMismatch(
+ errorSubClass = "UNEXPECTED_INPUT_TYPE",
+ messageParameters = Map(
+ "paramIndex" -> ordinalNumber(index),
+ "requiredType" -> requiredType,
+ "inputSql" -> toSQLExpr(expr),
+ "inputType" -> toSQLType(expr.dataType)))
+ }
+ }
+ result
+ }
+
+ override def left: Expression = min
+ override def right: Expression = max
+
+ override def seedExpression: Expression = seed
+ override def withNewSeed(newSeed: Long): Expression = {
+ val result = Uniform(min, max)
+ result.seed = Literal(newSeed, LongType)
+ result
+ }
+
+ override def withNewChildrenInternal(newFirst: Expression, newSecond:
Expression): Expression =
+ Uniform(newFirst, newSecond)
+
+ override def replacement: Expression = {
+ def cast(e: Expression, to: DataType): Expression = if (e.dataType == to)
e else Cast(e, to)
+ cast(Add(
+ cast(min, DoubleType),
+ Multiply(
+ Subtract(
+ cast(max, DoubleType),
+ cast(min, DoubleType)),
+ Rand(seed))),
+ dataType)
+ }
+}
+
+object Uniform {
+ lazy val random = new Random()
Review Comment:
Update on this: I was able to split the `UnaryExpression` part of `RDG` into
a separate class and now `Uniform` can reuse the remainder of `RDG` to simplify
this.
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