Our Code - Revision history

Wikiuser at 09:46, 19 March 2016

2016-03-19T09:46:01Z

← Older revision		Revision as of 09:46, 19 March 2016
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	[[Serial and Parallel Pi Calculation]]		[[Serial and Parallel Pi Calculation]]

	[[Decision Forests]]		[[Decision Forests]]

Wikiuser at 09:45, 19 March 2016

2016-03-19T09:45:54Z

← Older revision		Revision as of 09:45, 19 March 2016
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	[[Serial and Parallel Pi Calculation]]		[[Serial and Parallel Pi Calculation]]
			[[Decision Forests]]

Wikiuser: Replaced content with "Serial and Parallel Pi Calculation"

2016-03-02T22:41:38Z

Replaced content with "Serial and Parallel Pi Calculation"

Show changes

Wikiuser at 18:39, 2 March 2016

2016-03-02T18:39:41Z

← Older revision		Revision as of 18:39, 2 March 2016
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	comm = MPI.COMM_WORLD # comm is an mpi4py.MPI object representing the "world" of the cluster.		comm = MPI.COMM_WORLD # comm is an mpi4py.MPI object representing the "world" of the cluster.
	rank = comm.Get_rank() # That is, all the nodes and all the CPUs of the nodes, etc.		rank = comm.Get_rank() # That is, all the nodes and all the CPUs of the nodes, etc.
	if rank == 0: # Each cpu on each node is given an integer "rank" (0, 1, 2, 3,...)		if rank == 0: # The head does this if block # Each cpu on each node is given an integer "rank" (0, 1, 2, 3,...)
	start = time.time() # Usually, rank 0 is called the "head" node and assigns jobs to the		start = time.time() # Usually, rank 0 is called the "head" node and assigns jobs to the
	i = int(sys.argv[1]) # higher-ranked "worker" nodes. The worker nodes do their jobs and		i = int(sys.argv[1]) # higher-ranked "worker" nodes. The worker nodes do their jobs and
Line 99:		Line 99:
	print(pi)		print(pi)
	print("MPI pi approx time: {} seconds".format(elapsed))		print("MPI pi approx time: {} seconds".format(elapsed))
	else: # The workers do this block.		else: # The workers each do this block.
	data = comm.recv(source=0) # They receive the list of terms to calculate, do the calculation and		data = comm.recv(source=0) # They receive the list of terms to calculate, do the calculation and
	pi_appr = nthTerm(data) # send the result back to the head		pi_appr = nthTerm(data) # send the result back to the head

Wikiuser at 18:28, 2 March 2016

2016-03-02T18:28:34Z

← Older revision		Revision as of 18:28, 2 March 2016
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	size = comm.Get_size() # subsequently send the results back to the head node to assemble and		size = comm.Get_size() # subsequently send the results back to the head node to assemble and
	workers = size - 1 # collate.		workers = size - 1 # collate.
	termsplits = []		termsplits = [] # initialize a list for splitting the task up among the workers.
	for x in range(workers):		for x in range(workers): # termsplits is a list of lists of terms the workers will compute
	termsplits.append(xrange(x, i+1, workers))		termsplits.append(xrange(x, i+1, workers)) # (different for each worker)
	for y, data in enumerate(termsplits):		for y, data in enumerate(termsplits): # This block sends data (a list of terms) to each worker
	dest = y + 1		dest = y + 1
	if dest >= size:		if dest >= size:
Line 91:		Line 91:
	comm.send(data, dest=dest)		comm.send(data, dest=dest)
	pi = 0		pi = 0
	for y in range(workers):		for y in range(workers): # In this block, the head receives the results from the workers and
	source = y + 1		source = y + 1 # adds them together to calculate pi
	print("Waiting for source:{}".format(source))		print("Waiting for source:{}".format(source))
	pi_appr = comm.recv(source=source)		pi_appr = comm.recv(source=source)
Line 99:		Line 99:
	print(pi)		print(pi)
	print("MPI pi approx time: {} seconds".format(elapsed))		print("MPI pi approx time: {} seconds".format(elapsed))
	else:		else: # The workers do this block.
	data = comm.recv(source=0)		data = comm.recv(source=0) # They receive the list of terms to calculate, do the calculation and
	pi_appr = nthTerm(data)		pi_appr = nthTerm(data) # send the result back to the head
	comm.send(pi_appr, dest=0)		comm.send(pi_appr, dest=0)

Wikiuser at 17:26, 2 March 2016

2016-03-02T17:26:20Z

← Older revision		Revision as of 17:26, 2 March 2016
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	def main():		def main():
	comm = MPI.COMM_WORLD		comm = MPI.COMM_WORLD # comm is an mpi4py.MPI object representing the "world" of the cluster.
	rank = comm.Get_rank()		rank = comm.Get_rank() # That is, all the nodes and all the CPUs of the nodes, etc.
	if rank == 0:		if rank == 0: # Each cpu on each node is given an integer "rank" (0, 1, 2, 3,...)
	start = time.time()		start = time.time() # Usually, rank 0 is called the "head" node and assigns jobs to the
	i = int(sys.argv[1])		i = int(sys.argv[1]) # higher-ranked "worker" nodes. The worker nodes do their jobs and
	size = comm.Get_size()		size = comm.Get_size() # subsequently send the results back to the head node to assemble and
	workers = size - 1		workers = size - 1 # collate.
	termsplits = []		termsplits = []
	for x in range(workers):		for x in range(workers):

Wikiuser at 16:52, 2 March 2016

2016-03-02T16:52:48Z

← Older revision		Revision as of 16:52, 2 March 2016
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	print("Elapsed time: {}.".format(elapsed))		print("Elapsed time: {}.".format(elapsed))

	if __name__ == '__main__':		if __name__ == '__main__': # this bit of code allow for using this program as a
	main()		main() # standalone program or as a module
	</pre>		</pre>
	This is simple enough, maybe you've even written something similar. I'll go over a few things.		This is simple enough, maybe you've even written something similar. I'll go over a few things.

Wikiuser at 16:43, 2 March 2016

2016-03-02T16:43:09Z

← Older revision		Revision as of 16:43, 2 March 2016
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	import sys		import sys
	import time		import time
	from decimal import *		from decimal import * # Python package for intuitive handling decimal numbers
	getcontext().prec = 50		getcontext().prec = 50

	def piApprox(n):		def piApprox(n):
Line 20:		Line 20:
	"""		"""
	pi = 0		pi = 0
	for i in xrange(n+1):		for i in xrange(n+1):
	sign = 1 if i % 2 == 0 else -1		sign = 1 if i % 2 == 0 else -1 # sign is +1 if i is even and -1 if i is odd
	pi += Decimal(sign * 2 * 3 ** (.5-i)) / Decimal(2 * i + 1)		pi += Decimal(sign * 2 * 3 ** (.5-i)) / Decimal(2 * i + 1) # Madhava-Leibniz series approximation for pi
	return pi		return pi


	def main():		def main():
	n = sys.argv[1]		n = sys.argv[1] # requires the program be called with a command line
	n = int(n)		n = int(n) # argument specifying the desired number of terms
	start = time.time()		start = time.time()
	pi = piApprox(n)		pi = piApprox(n)

Wikiuser at 06:03, 28 February 2016

2016-02-28T06:03:52Z

← Older revision		Revision as of 06:03, 28 February 2016
Line 40:		Line 40:
	This is simple enough, maybe you've even written something similar. I'll go over a few things.		This is simple enough, maybe you've even written something similar. I'll go over a few things.

	If you are unfamiliar with python 2.7, the line at the top -- from __future__ import division -- probably looks strange to you. All this is doing is telling python to compute divisions as floats and to not do integer division (that would really mess up our approximation).		-If you are unfamiliar with python 2.7, the line at the top -- from __future__ import division -- probably looks strange to you. All this is doing is telling python to compute divisions as floats and to not do integer division (that would really mess up our approximation).
	sys.argv[1] is telling python to take a look at the 1 index of the commandline arguments (where index 0 is the name of the file you are running)
			-sys.argv[1] is telling python to take a look at the 1 index of the commandline arguments (where index 0 is the name of the file you are running)
	For example, we would run this file like		For example, we would run this file like

Wikiuser at 06:02, 28 February 2016

2016-02-28T06:02:26Z

← Older revision		Revision as of 06:02, 28 February 2016
Line 43:		Line 43:
	sys.argv[1] is telling python to take a look at the 1 index of the commandline arguments (where index 0 is the name of the file you are running)		sys.argv[1] is telling python to take a look at the 1 index of the commandline arguments (where index 0 is the name of the file you are running)
	For example, we would run this file like		For example, we would run this file like

	[[File:piserial.png]]		[[File:piserial.png]]

	We can see the elapsed time was 3.26 seconds.		We can see the elapsed time was 3.26 seconds.
	Then we just run the piApprox(n) function and add up our n terms.		Then we just run the piApprox(n) function and add up our n terms.