1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
|
#!/usr/bin/env python3
# Filename: ftqviz.py
# Author: Darren Hart <dvhltc@us.ibm.com>
# Description: Plot the time and frequency domain plots of a times and
# counts log file pair from the FTQ benchmark.
# Prerequisites: numpy, scipy, and pylab packages. For debian/ubuntu:
# o python-numeric
# o python-scipy
# o python-matplotlib
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# Copyright (C) IBM Corporation, 2007
#
# 2007-Aug-30: Initial version by Darren Hart <dvhltc@us.ibm.com>
from numpy import *
from numpy.fft import *
from scipy import *
from pylab import *
from sys import *
from getopt import *
NS_PER_S = 1000000000
NS_PER_MS = 1000000
NS_PER_US = 1000
def smooth(x, wlen):
if x.size < wlen:
raise ValueError("Input vector needs to be bigger than window size.")
# reflect the signal to avoid transients... ?
s = r_[2*x[0]-x[wlen:1:-1], x, 2*x[-1]-x[-1:-wlen:-1]]
w = hamming(wlen)
# generate the smoothed signal
y = convolve(w/w.sum(), s, mode='same')
# recenter the the smoothed signal over the originals (slide along x)
y1 = y[wlen-1:-wlen+1]
return y1
def my_fft(x, sample_hz):
X = abs(fftshift(fft(x)))
freq = fftshift(fftfreq(len(x), 1.0/sample_hz))
return array([freq, abs(X)/len(x)])
def smooth_fft(timefile, countfile, sample_hz, wlen):
# The higher the sample_hz, the larger the required wlen (used to generate
# the hamming window). It seems that each should be adjusted by roughly the
# same factor
ns_per_sample = NS_PER_S / sample_hz
print("Interpolated Sample Rate: ", sample_hz, " HZ")
print("Hamming Window Length: ", wlen)
t = fromfile(timefile, dtype=int64, sep='\n')
x = fromfile(countfile, dtype=int64, sep='\n')
# interpolate the data to achieve a uniform sample rate for use in the fft
xi_len = (t[len(t)-1] - t[0])/ns_per_sample
xi = zeros(xi_len)
last_j = 0
for i in range(0, len(t)-1):
j = (t[i] - t[0])/ns_per_sample
xi[j] = x[i]
m = (xi[j]-xi[last_j])/(j-last_j)
for k in range(last_j + 1, j):
xi[k] = m * (k - last_j) + xi[last_j]
last_j = j
# smooth the signal (low pass filter)
try:
y = smooth(xi, wlen)
except ValueError as e:
exit(e)
# generate the fft
X = my_fft(xi, sample_hz)
Y = my_fft(y, sample_hz)
# plot the hamming window
subplot(311)
plot(hamming(wlen))
axis([0,wlen-1,0,1.1])
title(str(wlen)+" Point Hamming Window")
# plot the signals
subplot(312)
ts = arange(0, len(xi), dtype=float)/sample_hz # time signal in units of seconds
plot(ts, xi, alpha=0.2)
plot(ts, y)
legend(['interpolated', 'smoothed'])
title("Counts (interpolated sample rate: "+str(sample_hz)+" HZ)")
xlabel("Time (s)")
ylabel("Units of Work")
# plot the fft
subplot(313)
plot(X[0], X[1], ls='steps', alpha=0.2)
plot(Y[0], Y[1], ls='steps')
ylim(ymax=20)
xlim(xmin=-3000, xmax=3000)
legend(['interpolated', 'smoothed'])
title("FFT")
xlabel("Frequency")
ylabel("Amplitude")
show()
def usage():
print("usage: "+argv[0]+" -t times-file -c counts-file [-s SAMPLING_HZ] [-w WINDOW_LEN] [-h]")
if __name__=='__main__':
try:
opts, args = getopt(argv[1:], "c:hs:t:w:")
except GetoptError:
usage()
exit(2)
sample_hz = 10000
wlen = 25
times_file = None
counts_file = None
for o, a in opts:
if o == "-c":
counts_file = a
if o == "-h":
usage()
exit()
if o == "-s":
sample_hz = int(a)
if o == "-t":
times_file = a
if o == "-w":
wlen = int(a)
if not times_file or not counts_file:
usage()
exit(1)
smooth_fft(times_file, counts_file, sample_hz, wlen)
|
