private String toString(boolean withType, boolean shortForms, long maxCells) {
        if (! shortForms
            || type.rank() == 0
            || type.rank() > 1 && type.dimensions().stream().filter(TensorType.Dimension::isIndexed).anyMatch(d -> d.size().isEmpty())
            || type.dimensions().stream().filter(TensorType.Dimension::isMapped).count() > 1)
            return Tensor.toStandardString(this, withType, shortForms, maxCells);

        return (withType ? type + ":" : "") + index.contentToString(this, maxCells);
    }
Returns an iterator over the values of this tensor.
The iteration order is the same as for cellIterator.
vespajlib/src/main/java/com/yahoo/tensor/MixedTensor.java