Get number of CPU from cluster environment variable

hrm-hc/MAIN_multiproc.py

@@ -760,7 +760,8 @@ if __name__ == '__main__':
             MAXFTDSP = np.max(FT_dsp)
             RENORM_FT_DSP = FT_dsp/MAXFTDSP*SUMDSP
 
-            ncpu = 4  # int(os.environ.get('PBS_NUM_PPN', mp.cpu_count()))
+            # get number of CPU from cluster environment variable
+            ncpu = int(os.environ.get('PBS_NUM_PPN', mp.cpu_count()))
             log.info('Using {} CPU to compute images'.format(ncpu))
             pool = mp.Pool(processes=ncpu)
             tasks = []