How can I accumulate value in details in a header field?

Use the following function in an EAFieldsValuesCalculator entity flow to sum a field across all lines of a detail grid into a header field:

totalize(detailName, detailName.fieldName)

For example, to sum the n1 field across the details line grid into a header field:

n1 = totalize(details, details.n1)

Originally posted at https://answers.namasoft.com/question/811/ on 2019-03-06.