WUOXLOK3CHUS2F3IEE6IOPUJBXLWJU4AHGJP44PMM2NED2ALVKZQC
IBJK5HBMWKXUMHT7E2W5OVCA7SJYFRAHMJFP5K5CHWDQXBLEBC2QC
B7Y552HZXBV2PD22T7ZXGFJKUYU23A7XDWV4XZK46SGQKX7U45PQC
VAF66DTVLDWNG7N2PEQYEH4OH5SPSMFBXKPR2PU67IIM6CVPCJ7AC
#warning \ "TODO: Don't overcount vertex-centred grid boundaries; introduce a weight function"
#warning \
"TODO: Don't overcount vertex-centred grid boundaries; introduce a weight function"
return sqrt(fmax1(T(0), vol * sum2 - pow21(sum)));
return sqrt(fmax1(T(0), sum2 / vol - pow21(sum / vol)));