next up previous contents
Next: 5 Files produced by Up: User's Guide for the Previous: 3 GRID parallelization and   Contents

4 Parallelization

The PHonon package uses the same parallelization mechanisms of the QUANTUM ESPRESSO package. See the Developer manual in the Doc directory two levels above this one for more information. It is parallelized on plane-waves, pools, bands, and images. The -ortho flag is not used. Scalapack routines are not used in the ph.x code.

Each tensor should be collected as soon as it is calculated and all processors must have the same tensors. Please avoid to collect tensors in routines distant from where they are calculated. There might be exception to this rule for efficiency, but please try not to abuse for small arrays. Only collected quantities are saved on the .xml file, so they should not depend on the parallelization level. Note that only ionode writes the .xml files, so you have different xml files only for different images. The variables are then broadcasted to all processors in an image.



Paolo Giannozzi 2017-10-23