#!/usr/bin/python -Wall

# ================================================================
# John Kerl
# kerl at math dot arizona dot edu
# 2008-05-12
# ================================================================

from   __future__ import division # 1/2 = 0.5, not 0.
import random
from   math import *
import copy
import sys
import re

# ----------------------------------------------------------------
def usage():
	print >> sys.stderr, "Usage: %s [options]" % (sys.argv[0])
	print >> sys.stderr, "Options:"
	print >> sys.stderr, "  T=[number]"
	print >> sys.stderr, "  nt=[number]"
	sys.exit(1)

# ----------------------------------------------------------------
# Complex Brownian motion:  c_t = a_t + i b_t.

T  = 5
nt = 10000

argc = len(sys.argv)
for argi in range(1, argc):
	if   re.match(r'^T=',  sys.argv[argi]): T  = float(sys.argv[argi][2:])
	elif re.match(r'^nt=', sys.argv[argi]): nt = int  (sys.argv[argi][3:])
	else: usage()

dt = T/nt
t      = 0.0
At     = 0.0
Bt     = 0.0
sqrtdt = sqrt(dt)

while (t < T):

	print "%11.7f %11.7f %11.7f" % (t, At, Bt)

	dA  = random.gauss(0, sqrtdt)
	dB  = random.gauss(0, sqrtdt)

	At += dA
	Bt += dB
	t  += dt