To get the best overall performance of the QR decomposition, for input, output, and auxiliary data, use homogeneous numeric tables of the same type as specified in the

algorithmFPType

class template parameter.

QR decomposition in the online processing mode is at least as computationally complex as in the batch processing mode and has high memory requirements for storing auxiliary data between calls to the

compute()s

method. On the other hand, the online version of QR decomposition may enable you to hide the latency of reading data from a slow data source. To do this, implement load prefetching of the next data block in parallel with the

compute()

method for the current block.

Online processing mostly benefits QR decomposition when the matrix Q is not required. In this case, memory requirements for storing auxiliary data goes down from to .

Using QR decomposition in the distributed processing mode requires gathering local-node numeric tables on the master node. When the amount of local-node work is small, that is, when the local-node data set is small, the network data transfer may become a bottleneck. To avoid this situation, ensure that local nodes have a sufficient amount of work. For example, distribute the input data set across a smaller number of nodes.