"""Small but quite comprehensive example showing the use of PyTables.

The program creates an output file, 'tutorial1.h5'.  You can view it
with any HDF5 generic utility.

"""


import sys
from numarray import *
from tables import *


	#'-**-**-**-**-**-**- user record definition  -**-**-**-**-**-**-**-'

# Define a user record to characterize some kind of particles
class Particle(IsDescription):
    name      = StringCol(16)   # 16-character String
    idnumber  = Int64Col()      # Signed 64-bit integer
    ADCcount  = UInt16Col()     # Unsigned short integer
    TDCcount  = UInt8Col()      # unsigned byte
    grid_i    = Int32Col()      # integer
    grid_j    = IntCol()        # integer (equivalent to Int32Col)
    pressure  = Float32Col()    # float  (single-precision)
    energy    = FloatCol()      # double (double-precision)

print
print	'-**-**-**-**-**-**- file creation  -**-**-**-**-**-**-**-'

# The name of our HDF5 filename
filename = "tutorial1.h5"
    
print "Creating file:", filename

# Open a file in "w"rite mode
h5file = openFile(filename, mode = "w", title = "Test file")

print
print	'-**-**-**-**-**-**- group an table creation  -**-**-**-**-**-**-**-'

# Create a new group under "/" (root)
group = h5file.createGroup("/", 'detector', 'Detector information')
print "Group '/detector' created"

# Create one table on it
table = h5file.createTable(group, 'readout', Particle, "Readout example")
print "Table '/detector/readout' created"

# Get a shortcut to the record object in table
particle = table.row

# Fill the table with 10 particles
for i in xrange(10):
    particle['name']  = 'Particle: %6d' % (i)
    particle['TDCcount'] = i % 256    
    particle['ADCcount'] = (i * 256) % (1 << 16)
    particle['grid_i'] = i 
    particle['grid_j'] = 10 - i
    particle['pressure'] = float(i*i)
    particle['energy'] = float(particle['pressure'] ** 4)
    particle['idnumber'] = i * (2 ** 34)
    # Insert a new particle record
    particle.append()

# Flush the buffers for table
table.flush()

print
print	'-**-**-**-**-**-**- table data reading & selection  -**-**-**-**-**-'

# Read actual data from table. We are interested in collecting pressure values
# on entries where TDCcount field is greater than 3 and pressure less than 50
pressure = [ x['pressure'] for x in table
             if x['TDCcount']>3 and 20<=x['pressure']<50 ]
print "Last record read:"
print x
print "Field pressure elements satisfying the cuts ==>", pressure

# Read also the names with the same cuts
names = [ x['name'] for x in table
          if x['TDCcount'] > 3 and 20 <= x['pressure'] < 50 ]

print
print	'-**-**-**-**-**-**- array object creation  -**-**-**-**-**-**-**-'

print "Creating a new group called '/columns' to hold new arrays"
gcolumns = h5file.createGroup(h5file.root, "columns", "Pressure and Name")

print "Creating an array called 'pressure' under '/columns' group"
h5file.createArray(gcolumns, 'pressure', array(pressure), 
                   "Pressure column selection")

print "Creating another array called 'name' under '/columns' group"
h5file.createArray('/columns', 'name', names, "Name column selection")

# Close the file
h5file.close()
print "File '"+filename+"' created"

