diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/FunctionRegistry.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/FunctionRegistry.scala index 39875d7f216b2ddfe01a30da2e375821c15b70b5..a7816e327526f63ae91e045555a98e4144a0c01e 100644 --- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/FunctionRegistry.scala +++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/FunctionRegistry.scala @@ -111,6 +111,7 @@ object FunctionRegistry { expression[Log10]("log10"), expression[Log1p]("log1p"), expression[Pi]("pi"), + expression[Log2]("log2"), expression[Pow]("pow"), expression[Rint]("rint"), expression[Signum]("signum"), diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/math.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/math.scala index e1d8c9a0cdb5a01244f831a7ce18b055706f5d1b..97e960b8d6422a7db5f84cb321e99a14f8a2e165 100644 --- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/math.scala +++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/math.scala @@ -161,6 +161,23 @@ case class Floor(child: Expression) extends UnaryMathExpression(math.floor, "FLO case class Log(child: Expression) extends UnaryMathExpression(math.log, "LOG") +case class Log2(child: Expression) + extends UnaryMathExpression((x: Double) => math.log(x) / math.log(2), "LOG2") { + override def genCode(ctx: CodeGenContext, ev: GeneratedExpressionCode): String = { + val eval = child.gen(ctx) + eval.code + s""" + boolean ${ev.isNull} = ${eval.isNull}; + ${ctx.javaType(dataType)} ${ev.primitive} = ${ctx.defaultValue(dataType)}; + if (!${ev.isNull}) { + ${ev.primitive} = java.lang.Math.log(${eval.primitive}) / java.lang.Math.log(2); + if (Double.valueOf(${ev.primitive}).isNaN()) { + ${ev.isNull} = true; + } + } + """ + } +} + case class Log10(child: Expression) extends UnaryMathExpression(math.log10, "LOG10") case class Log1p(child: Expression) extends UnaryMathExpression(math.log1p, "LOG1P") diff --git a/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/MathFunctionsSuite.scala b/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/MathFunctionsSuite.scala index 1fe69059d39dac744b6cd0cc6c11bd9076eea644..864c954ee82cb752dde615998648357660decda5 100644 --- a/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/MathFunctionsSuite.scala +++ b/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/MathFunctionsSuite.scala @@ -185,6 +185,12 @@ class MathFunctionsSuite extends SparkFunSuite with ExpressionEvalHelper { testUnary(Log1p, math.log1p, (-10 to -2).map(_ * 1.0), expectNull = true) } + test("log2") { + def f: (Double) => Double = (x: Double) => math.log(x) / math.log(2) + testUnary(Log2, f, (0 to 20).map(_ * 0.1)) + testUnary(Log2, f, (-5 to -1).map(_ * 1.0), expectNull = true) + } + test("pow") { testBinary(Pow, math.pow, (-5 to 5).map(v => (v * 1.0, v * 1.0))) testBinary(Pow, math.pow, Seq((-1.0, 0.9), (-2.2, 1.7), (-2.2, -1.7)), expectNull = true) diff --git a/sql/core/src/main/scala/org/apache/spark/sql/functions.scala b/sql/core/src/main/scala/org/apache/spark/sql/functions.scala index 083f6b6bceee8a011363c52516431c973a639ebf..c5b77724aae17336698ccbc0b3e603a8968936a7 100644 --- a/sql/core/src/main/scala/org/apache/spark/sql/functions.scala +++ b/sql/core/src/main/scala/org/apache/spark/sql/functions.scala @@ -1084,7 +1084,7 @@ object functions { def log(columnName: String): Column = log(Column(columnName)) /** - * Computes the logarithm of the given value in Base 10. + * Computes the logarithm of the given value in base 10. * * @group math_funcs * @since 1.4.0 @@ -1092,7 +1092,7 @@ object functions { def log10(e: Column): Column = Log10(e.expr) /** - * Computes the logarithm of the given value in Base 10. + * Computes the logarithm of the given value in base 10. * * @group math_funcs * @since 1.4.0 @@ -1124,6 +1124,22 @@ object functions { */ def pi(): Column = Pi() + /** + * Computes the logarithm of the given column in base 2. + * + * @group math_funcs + * @since 1.5.0 + */ + def log2(expr: Column): Column = Log2(expr.expr) + + /** + * Computes the logarithm of the given value in base 2. + * + * @group math_funcs + * @since 1.5.0 + */ + def log2(columnName: String): Column = log2(Column(columnName)) + /** * Returns the value of the first argument raised to the power of the second argument. * diff --git a/sql/core/src/test/scala/org/apache/spark/sql/DataFrameFunctionsSuite.scala b/sql/core/src/test/scala/org/apache/spark/sql/DataFrameFunctionsSuite.scala index 171a2151e67aef07d4dd245eace80dea6ff31b28..659b64c185f43be0bfefda94cd04e8640216fc60 100644 --- a/sql/core/src/test/scala/org/apache/spark/sql/DataFrameFunctionsSuite.scala +++ b/sql/core/src/test/scala/org/apache/spark/sql/DataFrameFunctionsSuite.scala @@ -128,5 +128,17 @@ class DataFrameFunctionsSuite extends QueryTest { }) } + test("log2 functions test") { + val df = Seq((1, 2)).toDF("a", "b") + checkAnswer( + df.select(log2("b") + log2("a")), + Row(1)) + checkAnswer( + ctx.sql("SELECT LOG2(8)"), + Row(3)) + checkAnswer( + ctx.sql("SELECT LOG2(null)"), + Row(null)) + } }