SplitAddr split(TensorAddress fullAddr) {
            var mapAddrBuilder = new TensorAddress.Builder(sparseType);
            var idxAddrBuilder = new TensorAddress.Builder(denseType);
            for (int i = 0; i < fullType.dimensions().size(); i++) {
                var dim = fullType.dimensions().get(i);
                if (dim.isMapped()) {
                    mapAddrBuilder.add(dim.name(), fullAddr.objectLabel(i));
                } else {
                    idxAddrBuilder.add(dim.name(), fullAddr.objectLabel(i));
                }
            }
            var mapAddr = mapAddrBuilder.build();
            var idxAddr = idxAddrBuilder.build();
            return new SplitAddr(mapAddr, idxAddr);
        }
The <i>filter_subspaces</i> tensor function selects some cells or subspaces in a mapped or mixed tensor

@author arnej
vespajlib/src/main/java/com/yahoo/tensor/functions/FilterSubspaces.java