private void decodeDoubleCells(DimensionSizes sizes, IndexedTensor.BoundBuilder builder, GrowableByteBuffer buffer) {
        for (long i = 0; i < sizes.totalSize(); i++)
            builder.cellByDirectIndex(i, buffer.getDouble());
    }
Returns dimension sizes from a type consisting of fully specified, indexed dimensions only
vespajlib/src/main/java/com/yahoo/tensor/serialization/DenseBinaryFormat.java