How to use sqrt on Double in Spark Scala
I am trying to calculate Root Mean Square Error (RMSE) manually on Spark (Scala 2.11)
As screenshot above, I calculate Square Error (SE) for each row
val predicted_with_sqr_err = predicted.withColumn("se", pow(($"medianHouseValue" - $"prediction"), lit(2)))
Then I calculate Mean Square Error (MSE)
val sum_se = predicted_with_sqr_err.agg(sum("se")).first.get(0)
val sum_se_double = sum_se.toString.toDouble
val mean_sqr_err = (1.0/predicted_with_sqr_err.count)*sum_se_double
It worked fine. But when I trying to square root to calculate Root Mean Square Error (RMSE).
val root_mean_sqr_err = sqrt(mean_sqr_err)
It give error:
<console>:83: error: overloaded method value sqrt with alternatives:
(colName: String)org.apache.spark.sql.Column <and>
(e: org.apache.spark.sql.Column)org.apache.spark.sql.Column
cannot be applied to (Double)
val root_mean_sqr_err = sqrt(mean_sqr_err)
How should I fix ?
scala apache-spark apache-zeppelin
asked Nov 12 '18 at 12:26
Haha TTpro
1,42031031
add a comment |
I am trying to calculate Root Mean Square Error (RMSE) manually on Spark (Scala 2.11)
As screenshot above, I calculate Square Error (SE) for each row
val predicted_with_sqr_err = predicted.withColumn("se", pow(($"medianHouseValue" - $"prediction"), lit(2)))
Then I calculate Mean Square Error (MSE)
val sum_se = predicted_with_sqr_err.agg(sum("se")).first.get(0)
val sum_se_double = sum_se.toString.toDouble
val mean_sqr_err = (1.0/predicted_with_sqr_err.count)*sum_se_double
It worked fine. But when I trying to square root to calculate Root Mean Square Error (RMSE).
val root_mean_sqr_err = sqrt(mean_sqr_err)
It give error:
<console>:83: error: overloaded method value sqrt with alternatives:
(colName: String)org.apache.spark.sql.Column <and>
(e: org.apache.spark.sql.Column)org.apache.spark.sql.Column
cannot be applied to (Double)
val root_mean_sqr_err = sqrt(mean_sqr_err)
How should I fix ?
scala apache-spark apache-zeppelin
asked Nov 12 '18 at 12:26
Haha TTpro
1,42031031
add a comment |
I am trying to calculate Root Mean Square Error (RMSE) manually on Spark (Scala 2.11)
As screenshot above, I calculate Square Error (SE) for each row
val predicted_with_sqr_err = predicted.withColumn("se", pow(($"medianHouseValue" - $"prediction"), lit(2)))
Then I calculate Mean Square Error (MSE)
val sum_se = predicted_with_sqr_err.agg(sum("se")).first.get(0)
val sum_se_double = sum_se.toString.toDouble
val mean_sqr_err = (1.0/predicted_with_sqr_err.count)*sum_se_double
It worked fine. But when I trying to square root to calculate Root Mean Square Error (RMSE).
val root_mean_sqr_err = sqrt(mean_sqr_err)
It give error:
<console>:83: error: overloaded method value sqrt with alternatives:
(colName: String)org.apache.spark.sql.Column <and>
(e: org.apache.spark.sql.Column)org.apache.spark.sql.Column
cannot be applied to (Double)
val root_mean_sqr_err = sqrt(mean_sqr_err)
How should I fix ?
scala apache-spark apache-zeppelin
asked Nov 12 '18 at 12:26
Haha TTpro
1,42031031
I am trying to calculate Root Mean Square Error (RMSE) manually on Spark (Scala 2.11)
As screenshot above, I calculate Square Error (SE) for each row
val predicted_with_sqr_err = predicted.withColumn("se", pow(($"medianHouseValue" - $"prediction"), lit(2)))
Then I calculate Mean Square Error (MSE)
val sum_se = predicted_with_sqr_err.agg(sum("se")).first.get(0)
val sum_se_double = sum_se.toString.toDouble
val mean_sqr_err = (1.0/predicted_with_sqr_err.count)*sum_se_double
It worked fine. But when I trying to square root to calculate Root Mean Square Error (RMSE).
val root_mean_sqr_err = sqrt(mean_sqr_err)
It give error:
<console>:83: error: overloaded method value sqrt with alternatives:
(colName: String)org.apache.spark.sql.Column <and>
(e: org.apache.spark.sql.Column)org.apache.spark.sql.Column
cannot be applied to (Double)
val root_mean_sqr_err = sqrt(mean_sqr_err)
How should I fix ?
scala apache-spark apache-zeppelin
scala apache-spark apache-zeppelin
asked Nov 12 '18 at 12:26
Haha TTpro
1,42031031
asked Nov 12 '18 at 12:26
Haha TTpro
1,42031031
asked Nov 12 '18 at 12:26
Haha TTpro
1,42031031
asked Nov 12 '18 at 12:26
Haha TTpro
1,42031031
asked Nov 12 '18 at 12:26
Haha TTpro
1,42031031
1,42031031
add a comment |
add a comment |
1 Answer
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The problem is that you are using sqrt function which is defined in Spark SQL. This function should be used only as a part of Spark SQL DSL (in selections, aggregations, etc.).
It takes Column or String as a parameter but you are trying to pass Double.
Instead use sqrt function which is defined in scala.math package:
val root_mean_sqr_err = math.sqrt(mean_sqr_err)
answered Nov 12 '18 at 12:44
Vitalii Honta
1878
add a comment |
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1 Answer
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active
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votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
The problem is that you are using sqrt function which is defined in Spark SQL. This function should be used only as a part of Spark SQL DSL (in selections, aggregations, etc.).
It takes Column or String as a parameter but you are trying to pass Double.
Instead use sqrt function which is defined in scala.math package:
val root_mean_sqr_err = math.sqrt(mean_sqr_err)
answered Nov 12 '18 at 12:44
Vitalii Honta
1878
add a comment |
The problem is that you are using sqrt function which is defined in Spark SQL. This function should be used only as a part of Spark SQL DSL (in selections, aggregations, etc.).
It takes Column or String as a parameter but you are trying to pass Double.
Instead use sqrt function which is defined in scala.math package:
val root_mean_sqr_err = math.sqrt(mean_sqr_err)
answered Nov 12 '18 at 12:44
Vitalii Honta
1878
add a comment |
The problem is that you are using sqrt function which is defined in Spark SQL. This function should be used only as a part of Spark SQL DSL (in selections, aggregations, etc.).
It takes Column or String as a parameter but you are trying to pass Double.
Instead use sqrt function which is defined in scala.math package:
val root_mean_sqr_err = math.sqrt(mean_sqr_err)
answered Nov 12 '18 at 12:44
Vitalii Honta
1878
The problem is that you are using sqrt function which is defined in Spark SQL. This function should be used only as a part of Spark SQL DSL (in selections, aggregations, etc.).
It takes Column or String as a parameter but you are trying to pass Double.
Instead use sqrt function which is defined in scala.math package:
val root_mean_sqr_err = math.sqrt(mean_sqr_err)
answered Nov 12 '18 at 12:44
Vitalii Honta
1878
answered Nov 12 '18 at 12:44
Vitalii Honta
1878
answered Nov 12 '18 at 12:44
Vitalii Honta
1878
answered Nov 12 '18 at 12:44
Vitalii Honta
1878
1878
add a comment |
add a comment |
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