I have another question about udf and don't know how to correctly use it in schema file in the following.

There is a problem about userdefinedfunction (UDF) in mondrian 3.x and expect to be solved. That is,
I can't aggregate the measure from the calculatedMember obtained by udf (i.e., using java code) instead of the base-measure, existed column, according to my scenarios, i have to compute such index via udf using java code, as is known, however, it got failed and an error occurred when i tried to aggregate the calculated measure as follows:

saiku.web.export.excel.name=saiku-export
11:17:56,775 WARN [AggregateFunDef ] Unable to determine aggregator for non-base measures in 2nd parameter of Aggregate(), summing: [Measures].[myCalc]

And is there any solution to aggregate the calculatedMember from udf? Really it puzzled me a long time, thanks.

attached parts of .xml file
<schema name="tests">
<cube name="testc">

<CalculatedMember name="myCalc" dimension="Measures" visible=true >
<Formula>myUdf("test")
</Formula>
</CalculatedMember>

<CalculatedMember name="myCalc_fi" dimension="Measures" visible="true" >
<Formula>
Aggregate(MTD([Date].[Date Year].Members),[Measures].[myCalc])
</Formula>
</CalculatedMember>

</cube>
</schema>