the 2 files you mention are created by OpenSees when it runs the Ex1b.Portal2D.EQ.tcl script. The following are the two line in the script that generate these files:
recorder EnvelopeNode -file PFA.out -timeSeries 1 -node 3 -dof 1 accel; # Peak Floor Absolute Acceleration
recorder EnvelopeDrift -file PID.out -iNode 1 -jNode 3 -dof 1 -perpDirn 2
it is the python script PortalFrameSampling.py that causes OpenSees to run multip[le times to perform the sampling. If you look you will see that for each invocation of OpenSees, the python script creates a directory, runs OpenSees in that directory, reads the results in the 2 files you are looking for from that directory, and then DELETES the directory. If you want to see the files after the python script is run you will need to comment out the line removing the directory (line 40):
shutil.rmtree(sampleName)
note: depending on your version of python you may need to change the prints at the bottom of the. said python script to something like:
#Printing results
print ('Mean Peak Floor Acceleration: ', np.mean(PFA))
print ('Peak Floor Acceleration Std. Dev: ', np.std(PFA))
print ('Mean Peak Drift: ', np.mean(PID))
print ('Peak Drift Std. Dev.: ', np.std(PID))
