QtConcurrent map with QMap as input sequence

Question

I have a data structure of QMap<QList<QList<float>>>. I want to compare every single float with a threshold value using multi-threading(as the amount of float is huge, 1000*800*800). However QtConcurrent::map only accepts QList or QVector as input sequence type, but I require the QMap.key() component in my map function to perform other stuff, is there any solution to it? Thank you.