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I'm trying solve a system of coupled ordinary differential equations, formed by 7 ODEs in python, using solve_ivp or either implement a fuction for RK4.
The general physical problem is as follows:
Cooling of photovoltaic modules with heat exchanger coupling to the module. In this way, the module generates electrical energy and thermal energy.
I have a polynomial function, G(t) = 9.8385e-13*t^4 - 1.82918e-8*t^3 + 5.991355e-05*t^2 + 2.312059e-1*t + 25, which works for an approximate range of 0 < t < 9000, which represents solar radiation as a function of time of day.
This function was obtained through a "polyfit" applied to real data (file upload here. Its a CSV - https://files.fm/u/9y4evkf6c).
This function is used as input for the ODEs, which represent an electrical and a thermal system as a function of time.
To solve the electrical model, I created some scripts that solve the diode equation for the photovoltaic module in question, and the output of this script is the photovoltaic power (called in the PPV thermal model) generated as a function of the module temperature and radiation. This script works great and solves part of my problem.
My difficulty lies in solving the equations of the thermal model, which receives as input parameters G(t) and PPV.
The equations result in this system:
System of EDOS
Labels:
Tvidro = Tglass = T1
Tcel = Tpv = T2
Ttedlar = T3
Tabs = Tabsorber = T4
Ttubo = Ttube = T5
Tfsai = Tfluid_out = T6
Tiso = Tinsulation = T7
Using method/function for RK4, the complete code is like this (you can go direct to part "#DEFINE MODEL EQUATIONS - ODES)" :
import numpy as np
import matplotlib.pyplot as plt
import csv
from numpy.polynomial.polynomial import polyval
############################################################
with open('directory of data called teste_dados_radiacao',"r") as i:
rawdata = list(csv.reader(i, delimiter = ";"))
exampledata = np.array(rawdata[1:], dtype=float)
xdata = exampledata[:,0]
ydata = exampledata[:,1]
curve = np.array(np.polyfit(xdata, ydata, 4))
rev_curve = np.array(list(reversed(curve)), dtype=float)
print(rev_curve)
#G_ajustado = polyval(xdata, rev_curve)
""" plt.plot(xdata, ydata, label = "dados experimentais")
plt.plot(xdata, model, label = "model")
plt.legend()
plt.show() """
#############################################################
#CONSTANTS
Tamb = 25 #°C #ambient temperatura
SIGMA = 5.67e-8 #W/m2K4
E_VIDRO = 0.90 #between 0.85 e 0.83 #nasrin2017 0.04
VENTO = 2 #m/s
T_GROUND = Tamb + 2 #°C
T_CEU = 0.00552*Tamb**1.5
Vf = 1 #m/s
Do = 10e-3 #m
Di = 8e-3 #m
NS = 6*10 #number of cells
T_F_ENT = 20 #°C
#INPUTS
Tcel = 25
Tv = 25
Tiso = 30
Av = 1.638*0.982
ALPHA_VIDRO = 0.9
L_VIDRO = 3e-3 #m
RHO_VIDRO = 2500 #kg/m3
M_VIDRO = Av*L_VIDRO*RHO_VIDRO #kg
CP_VIDRO = 500 #j/kgK
K_VIDRO = 2 #W/mK
TAU_VIDRO = 0.95
Pac = 0.85
H_CELL = 0.156 #m
A_CELL = NS*H_CELL**2
ALPHA_CELL = 0.9
L_CEL = 3e-3
RHO_CEL = 2330
M_CEL = A_CELL*L_CEL*RHO_CEL #kg - estimated
CP_CEL = 900 #J/kgK
K_CEL = 140 #W/mK
BETA_T = 0.43/100 # %/°C
N_ELE_REF = 0.1368 #13.68%
N_ELE = N_ELE_REF*(1 - BETA_T*(Tcel - 25)) #273 + 25 - tcel kelvin
A_tedlar = Av
L_TEDLAR = 0.33e-3
RHO_TEDLAR = 1500
M_TEDLAR = Av*L_TEDLAR*RHO_TEDLAR
CP_TEDLAR = 1090 #1090 OU 2090
K_TEDLAR = 0.35
ALPHA_TEDLAR = 0.34 #doc nasa ou zero
#parameters
RHO_ABS = 2700
A_ABS = Av
CP_ABS =900
L_ABS = 3e-3 #mm
M_ABS = A_ABS*RHO_ABS*L_ABS
K_ABS = 300
A_ABS_TUBO = 10*1.60*0.01+0.154*9*0.01
A_ABS_ISO = Av-A_ABS_TUBO
RHO_TUBO = 2700
CP_TUBO = 900
N_TUBOS = 10
L_TUBO = N_TUBOS*1.6
M_TUBO = RHO_TUBO*L_TUBO*(3.1415/4)*(Do**2 - Di**2)
K_TUBO = 300
A_TUBO_F = 0.387 #pi*Di*(L*10 VOLTAS + R(156MM)*9)
A_TUBO_ISO = 0.484 #pi*Do*(L*10 VOLTAS + R(156MM)*9)
A_ISO = Av
RHO_ISO = 50
L_ISO = 40e-3
M_ISO = A_ISO*RHO_ISO*L_ISO
CP_ISO = 670
K_ISO = 0.0375
E_ISO = 0.75 #ESTIMATED
RHO_FLUIDO = 997
M_FLUIDO = L_TUBO*(3.1415/4)*Di**2*RHO_FLUIDO
CP_FLUIDO = 4186 #j/kgK
MI_FLUIDO = 0.890e-3 #Pa*s ou N/m2 * s
K_FLUIDO = 0.607
M_PONTO = 0.05 #kg/s ou 0.5 kg/m3
#DIMENSIONLESS
Pr = CP_FLUIDO*MI_FLUIDO/K_FLUIDO #water 25°C
Re = RHO_FLUIDO*Vf*Di/MI_FLUIDO
if (Re<=2300):
Nuf = 4.364
else:
Nuf = 0.023*(Re**0.8)*(Pr*0.4)*Re
#COEFFICIENTS
h_rad_vidro_ceu = SIGMA*E_VIDRO*(Tv**2 - T_CEU)*(Tv + T_CEU)
h_conv_vidro_amb = 2.8 + 3*VENTO
h_conv_tubo_fluido = 0.5*30#Nuf
h_cond_vidro_cel = 1/((L_VIDRO/K_VIDRO) + (L_CEL/K_CEL))
h_cond_cel_tedlar = 1/((L_TEDLAR/K_TEDLAR) + (L_CEL/K_CEL))
h_cond_tedlar_abs = 1/((L_TEDLAR/K_TEDLAR) + (L_ABS/K_ABS))
h_cond_abs_tubo = 1/((L_TUBO/K_TUBO) + (L_ABS/K_ABS))
h_cond_abs_iso = 1/((L_ISO/K_ISO) + (L_ABS/K_ABS))
h_cond_tubo_iso = 1/((L_ISO/K_ISO) + (L_TUBO/K_TUBO))
h_conv_iso_amb = h_conv_vidro_amb
h_rad_iso_ground = SIGMA*E_ISO*(Tiso**2 - T_GROUND**2)*(Tiso + T_GROUND)
#GROUPS
A1 = (1/(M_VIDRO*CP_VIDRO))*(ALPHA_VIDRO*Av)#*G(t)) G_ajustado = polyval(dt,rev_curve)
A2 = (1/(M_VIDRO*CP_VIDRO))*(Av*(h_rad_vidro_ceu + h_conv_vidro_amb + h_cond_vidro_cel))
A3 = (1/(M_VIDRO*CP_VIDRO))*Av*h_cond_vidro_cel
A4 = (1/(M_VIDRO*CP_VIDRO))*Av*(h_conv_vidro_amb + h_rad_vidro_ceu)
A5 = (1/(M_CEL*CP_CEL))*(Pac*A_CELL*TAU_VIDRO*ALPHA_CELL) #*G(t)
A6 = -1*A5*N_ELE #*G(t)
A7 = (1/(M_CEL*CP_CEL))*A_CELL*h_cond_vidro_cel
A8 = (1/(M_CEL*CP_CEL))*A_CELL*(h_cond_vidro_cel + h_cond_cel_tedlar)
A9 = (1/(M_CEL*CP_CEL))*A_CELL*h_cond_cel_tedlar
A10 = (1/(M_TEDLAR*CP_TEDLAR))*A_tedlar*(1 - Pac)*TAU_VIDRO*ALPHA_TEDLAR#G(t)
A11 = (1/(M_TEDLAR*CP_TEDLAR))*A_tedlar*(h_cond_cel_tedlar + h_cond_tedlar_abs)
A12 = (1/(M_TEDLAR*CP_TEDLAR))*A_tedlar*h_cond_cel_tedlar
A13 = (1/(M_TEDLAR*CP_TEDLAR))*A_tedlar*h_cond_tedlar_abs
A14 = (1/(M_ABS*CP_ABS))*A_ABS*h_cond_tedlar_abs
A15 = (1/(M_ABS*CP_ABS))*(A_ABS*h_cond_tedlar_abs + A_ABS_TUBO*h_cond_abs_tubo + A_ABS_ISO*h_cond_abs_iso)
A16 = (1/(M_ABS*CP_ABS))*A_ABS_TUBO*h_cond_abs_tubo
A17 = (1/(M_ABS*CP_ABS))*A_ABS_ISO*h_cond_abs_iso
A18 = (1/(M_TUBO*CP_TUBO))*A_ABS_TUBO*h_cond_abs_tubo
A19 = (1/(M_TUBO*CP_TUBO))*(A_ABS_TUBO*h_cond_abs_tubo + A_TUBO_F*h_conv_tubo_fluido + A_TUBO_ISO*h_cond_tubo_iso)
A20 = (1/(M_TUBO*CP_TUBO))*A_TUBO_F*h_conv_tubo_fluido*0.5
A21 = (1/(M_TUBO*CP_TUBO))*A_TUBO_ISO*h_cond_tubo_iso
A22 = (1/(M_FLUIDO*CP_FLUIDO))*A_TUBO_F*h_conv_tubo_fluido
A23 = (1/(M_FLUIDO*CP_FLUIDO))*(A_TUBO_F*h_conv_tubo_fluido*0.5 + M_PONTO*CP_FLUIDO)
A24 = (1/(M_FLUIDO*CP_FLUIDO))*(T_F_ENT*(M_PONTO*CP_FLUIDO - h_conv_tubo_fluido*A_TUBO_F*0.5))
A25 = (1/(M_ISO*CP_ISO))*A_ABS_ISO*h_cond_abs_iso
A26 = (1/(M_ISO*CP_ISO))*(A_ABS_ISO*h_cond_abs_iso + A_TUBO_ISO*h_cond_tubo_iso + A_ISO*h_conv_iso_amb + A_ISO*h_rad_iso_ground)
A27 = (1/(M_ISO*CP_ISO))*A_TUBO_ISO*h_cond_tubo_iso
A28 = (1/(M_ISO*CP_ISO))*A_ISO*(h_conv_iso_amb*Tamb + h_rad_iso_ground*T_GROUND)
#DEFINE MODEL EQUATIONS - ODES - (GLASS, PV CELL, TEDLAR, ABSORBER, TUBE, FLUID, INSULATION) # dT1dt = A1*G_ajustado - A2*x[0] + A3*x[1] + A4 # dT2dt = A5*G_ajustado - A6*G_ajustado + A7*x[0] - A8*x[1] + A9*x[2]# dT3dt = A10*G_ajustado - A11*x[2] + A12*x[1] +A13*x[3]
def SysEdo(x, k):#tv-x[0] tcel-x[1] ttedlar-x[2] tabs-x[3] ttubo-x[4] tiso-x[5] tfs-x[6]
dT1dt = A1*polyval(k,rev_curve) - A2*x[0] + A3*x[1] + A4
dT2dt = A5*polyval(k,rev_curve) - A6*polyval(k,rev_curve) + A7*x[0] - A8*x[1] + A9*x[2]
dT3dt = A10*polyval(k,rev_curve) - A11*x[2] + A12*x[1] +A13*x[3]
dT4dt = A14*x[2] - A15*x[3] + A16*x[4] + A17*x[5]
dT5dt = A18*x[3] - A19*x[4] + A20*x[6] + A20*T_F_ENT + A21*x[5]
dT6dt = A22*x[4] - A23*x[6] + A24
dT7dt = A25*x[3] - A26*x[5] + A27*x[4] + A28
Tdot = np.array([dT1dt, dT2dt, dT3dt, dT4dt, dT5dt, dT6dt, dT7dt])
return Tdot
#RungeKutta4
def RK4(f, x0, t0, tf, dt):
t = np.arange(t0, tf, dt) #time vector
nt = t.size #lenght of time vector
nx = x0.size #length of state variables?
x = np.zeros((nx,nt)) #initialize 2D vector
x[:,0] = x0 #initial conditions
#RK4 constants
for k in range(nt-1):
k1 = dt*f(t[k], x[:,k],k)
k2 = dt*f(t[k] + dt/2, x[:,k] + k1/2, k)
k3 = dt*f(t[k] + dt/2, x[:,k] + k2/2, k)
k4 = dt*f(t[k] + dt, x[:,k] + k3, k)
dx = (k1 + 2*k2 + 2*k2 + k4)/6
x[:,k+1] = x[:,k] + dx
return x,t
#Define problems
f = lambda t, x, k : SysEdo(x, k)
#initial state - t0 is initial time - tf is final time - dt is time step
x0 = np.array([30, 30, 30, 30, 30, 30, 30])
t0 = 0
tf = 1000
dt = 1
#EDO SOLVE
x, t = RK4(f, x0, t0, tf, dt)
plt.figure()
plt.plot(t, x[0], '-', label='Tvidro')
"""
plt.plot(t, x[1], '-', label='Tpv')
plt.plot(t, x[2], '-', label='Ttedlar')
plt.plot(t, x[3], '-', label='Tabs')
plt.plot(t, x[4], '-', label='Tiso')
plt.plot(t, x[5], '-', label='Ttubo')
plt.plot(t, x[6], '-', label='Tfsai')"""
plt.title('Gráfico')
plt.legend(['Tvidro', 'Tpv', 'Ttedlar', 'Tabs', 'Tiso', 'Ttubo', 'Tfsai'], shadow=False)
plt.xlabel('t (s)')
plt.ylabel('Temperatura (°C)')
plt.xlim(0,20)
plt.ylim(0,150)
plt.grid('on')
plt.show()
Thank you in advance, I am also open to completely start the implementation from scratch if there is a better way to do this with python or matlab.
You can just replace
x, t = RK4(f, x0, t0, tf, dt)
with
t = arange(t0,tf+0.5*dt,dt)
res = solve_ivp(f,(t0,tf),x0,t_eval=t,args=(k,), method="DOP853", atol=1e-6,rtol=1e-8)
x = res.y[0]
Adapt the last 3 parameters to your liking.
I have this relation to which I write the code using python to compute it , I am not sure if the code is right or not. Could you please give me any advice if it is true or how I can improve the code??, thanks
import matplotlib.pyplot as plt
import numpy as np
from scipy.special import comb
from scipy.constants import k
from numpy import arange
p12 = 1 # system initial state 12
w0 = 1 # system
wn = 0 # wb/w0 bath
U = 0.1
N = 50
n = (N/2)
a =0.007
t = 1000# Time
Z = 2**N * (np.cosh(U*wn/2))**N
q12 = []
f11 = []
def Jrange(start, n, step):
numelements = int((stop-start)/float(step))
for i in range(numelements+1):
yield start + i*step
def trange(tstart,tstop,tstep):
tnumelements = int((tstop-tstart)/float(tstep))
for i in range(tnumelements+1):
yield tstart + i*tstep
for t in trange(tstart,tstop,tstep):
roh2 = 0
roh12 = 0
roh1 = 0
roh11 = 0
for J in Jrange (0,stop,1) :
Nj = (comb (N,(n+J))) - (comb (N,(n+J+1)))
for m in arange (-J,J+1):
r1 = np.sqrt (J*(J + 1) - m*(m + 1)) #r+
r2 = np.sqrt (J*(J + 1) - m*(m - 1)) #r-
Omega1 = (w0 - wn) + (4 *a*(m + (1/2)))/(np.sqrt(N)) #Omeg+
gamma1 = np.sqrt( (Omega1**2 /4)+ (4*a**2 * r1**2)/N) # gamma+
Omega2 =-(w0 - wn) - (4 *a*(m - (1/2)))/(np.sqrt(N)) #Omega-
gamma2 = np.sqrt( (Omega2**2 /4)+ (4*a**2 * r2**2)/N)#gamma-
A1 = np.cos(gamma1*t)
B1 = np.sin(gamma1*t)
A2 = np.cos(gamma2*t)
B2 = np.sin(gamma2*t)
C = np.exp(-m*U*wn)
H12 = C * (A1 - 1j*B1*Omega1/(2*gamma1)) * ((A2 +1j*B2*Omega2/(2*gamma2))
H2 = r2**2 * B2**2 * ((4*a**2)/ (gamma2**2 * N))
H1 = A1**2 + B1**2 *((Omega1**2)/ (4 * gamma1**2))
H11 = C * ((p11*H1) + (p22*H2))
roh11 = roh11+H11
roh12 = roh12 + H12
roh2= roh2 +roh12*Nj
roh1 = roh1 + roh11*Nj
Roh12 = roh2*D *p12*np.exp(1j*(w0-wn)*t)
Roh11 = roh1 *D
q12.append(Roh12)
f11.append(Roh11)
I'm working with RR peaks and want to derive the frequency domain measures for HRV to recreate the results from the native C package by Physionet (WFDB tools). Both signal processing and spectral analysis are new fields for me, but after a long week with trial an error I've hacked together some code based on the Astropy module after trying several other solutions.
from astropy.stats import LombScargle
import random
dy = 0.1 * random.randint(1,100)
t = drive01["time"].values
y = drive01["intervals"].values
frequency, power = LombScargle(t, y,dy).autopower(minimum_frequency=0.0,maximum_frequency=4)
plt.plot(frequency, power)
This creates a plot that looks quite similar to the plot from Physionets package.
Physionets HRV tools with the code get_hrv makes this plot
Then by calculating common frequency domain measures I get quite different results.
Pxx = np.nan_to_num(power)
Fxx = np.nan_to_num(frequency)
ulf = 0.003
vlf = 0.04
lf = 0.15
hf = 0.4
Fs = 15.5 # the sampling rate of the drive file
# find the indexes corresponding to the VLF, LF, and HF bands
vlf_freq_band = (Fxx >= ulf) & (Fxx <= vlf)
lf_freq_band = (Fxx >= vlf) & (Fxx <= lf)
hf_freq_band = (Fxx >= lf) & (Fxx <= hf)
tp_freq_band = (Fxx >= 0) & (Fxx <= hf)
# Calculate the area under the given frequency band
dy = 1.0 / Fs
VLF = np.trapz(y=abs(Pxx[vlf_freq_band]), x=None, dx=dy)
LF = np.trapz(y=abs(Pxx[lf_freq_band]), x=None, dx=dy)
HF = np.trapz(y=abs(Pxx[hf_freq_band]), x=None, dx=dy)
TP = np.trapz(y=abs(Pxx[tp_freq_band]), x=None, dx=dy)
LF_HF = float(LF) / HF
Python
'HF': 0.10918703853414605,
'LF': 0.050074418080717789,
'LF/HF': 0.45861137689028925,
'TP': 0.20150514290250854,
'VLF': 0.025953350304821571
From the Physionet package:
TOT PWR = 0.0185973
VLF PWR = 0.00372733
LF PWR = 0.00472635
HF PWR = 0.0101436
LF/HF = 0.465944
When comparing the results it looks like this:
Python Physionet
TP 0.201505143 0.0185973 Quite similar + decimal dif
HF 0.109187039 0.0101436 Quite similar + decimal dif
LF 0.050074418 0.00472635 Quite similar + decimal dif
VLF 0.02595335 0.00372733 Not similar
LF/HF 0.458611377 0.465944 Quite similar
The calculations in Python are based on the code from another Stackoverflow post but the fix he got from the respondent is based on a python module I'm not able to get working and he is not using the Lomb Periodgram. I'm very open for trying something else as well, as long as its working with uneven samples.
the data I'm working with is the drivedb from Physionet and I've used the Physionet packages to make a text file with RR peaks and time which is read into a Pandas DataFrame. The textfile can be found here
LombScargle based on the Astropy caculate power different with C package by Physionet (WFDB tools). I write lombscargle again in python and result the same with C package by Physionet (WFDB tools).
import numpy as np
import os
import math
import csv
from itertools import zip_longest
import time
DATA_PATH = '/home/quangpc/Desktop/Data/PhysionetData/mitdb/'
class FreqDomainClass:
#staticmethod
def power(freq, mag):
lo = [0, 0.0033, 0.04, 0.15]
hi = [0.0033, 0.04, 0.15, 0.4]
pr = np.zeros(4)
nbands = 4
for index in range(0, len(freq)):
pwr = np.power(mag[index], 2)
for n in range(0, nbands):
if (freq[index] >= lo[n]) and freq[index] <= hi[n]:
pr[n] += pwr
break
return pr
#staticmethod
def avevar(y):
var = 0.0
ep = 0.0
ave = np.mean(y)
for i in range(len(y)):
s = y[i] - ave
ep += s
var += s * s
var = (var - ep * ep / len(y)) / (len(y) - 1)
return var
def lomb(self, t, h, ofac, hifac):
period = max(t) - min(t)
z = h - np.mean(h)
f = np.arange(1 / (period * ofac), hifac * len(h) / (2 * period), 1 / (period * ofac))
f = f[:int(len(f) / 2) + 1]
f = np.reshape(f, (len(f), -1))
w = 2 * np.pi * f
lenght_t = len(t)
t = np.reshape(t, (lenght_t, -1))
t = np.transpose(t)
tau = np.arctan2(np.sum(np.sin(2 * w * t), axis=1), np.sum(np.cos(2 * w * t), axis=1)) / (2 * w)
tau = np.diag(tau)
tau = np.reshape(tau, (len(tau), -1))
tau = np.tile(tau, (1, lenght_t))
cos = np.cos(w * (t - tau))
sin = np.sin(w * (t - tau))
pc = np.power(np.sum(z * cos, axis=1), 2)
ps = np.power(np.sum(z * sin, axis=1), 2)
cs = pc / np.sum(np.power(cos, 2), axis=1)
ss = ps / np.sum(np.power(sin, 2), axis=1)
p = cs + ss
pwr = self.avevar(h)
nout = len(h)
p = p / (2 * pwr)
p = p / (nout / (2.0 * pwr))
return f, np.sqrt(p)
def lomb_for(self, t, h, ofac, hifac):
period = max(t) - min(t)
f = np.arange(1 / (period * ofac), hifac * len(h) / (2 * period), 1 / (period * ofac))
f = f[:int(len(f) / 2) + 1]
z = h - np.mean(h)
p = np.zeros(len(f))
for i in range(len(f)):
w = 2 * np.pi * f[i]
if w > 0:
twt = 2 * w * t
y = sum(np.sin(twt))
x = sum(np.cos(twt))
tau = math.atan2(y, x) / (2 * w)
wtmt = w * (t - tau)
cs = np.power(sum(np.multiply(z, np.cos(wtmt))), 2) / sum(np.power((np.cos(wtmt)), 2))
ss = np.power(sum(np.multiply(z, np.sin(wtmt))), 2) / sum(np.power((np.sin(wtmt)), 2))
p[i] = cs + ss
else:
p[i] = np.power(sum(np.multiply(z, t)), 1) / sum(np.power(t), 1)
pwr = self.avevar(h)
nout = len(h)
p = p / (2 * pwr)
p = p / (nout / (2.0 * pwr))
return f, np.sqrt(p)
def freq_domain(self, time, rr_intervals):
frequency, mag0 = self.lomb(time, rr_intervals, 4.0, 2.0)
frequency = np.round(frequency, 8)
mag0 = mag0 / 2.0
mag0 = np.round(mag0, 8)
result = self.power(frequency, mag0)
return result[0], result[1], result[2], result[3], result[0] + result[1] + result[2] + result[3], \
result[2] / result[3]
def time_domain(time, rr_intervals, ann):
sum_rr = 0.0
sum_rr2 = 0.0
rmssd = 0.0
totnn = 0
totnnn = 0
nrr = 1
totrr = 1
nnx = 0
nnn = 0
lastann = ann[0]
lastrr = int(rr_intervals[0])
lenght = 300
t = float(time[0])
end = t + lenght
i = 0
ratbuf = np.zeros(2400)
avbuf = np.zeros(2400)
sdbuf = np.zeros(2400)
for x in range(1, len(ann)):
t = float(time[x])
while t > (end+lenght):
i += 1
end += lenght
if t >= end:
if nnn > 1:
ratbuf[i] = nnn/nrr
sdbuf[i] = np.sqrt(((sdbuf[i] - avbuf[i]*avbuf[i]/nnn) / (nnn-1)))
avbuf[i] /= nnn
i += 1
nnn = nrr = 0
end += lenght
nrr += 1
totrr += 1
if ann[x] == 'N' and ann[x-1] == 'N':
rr_intervals[x] = int(rr_intervals[x])
nnn += 1
avbuf[i] += rr_intervals[x]
sdbuf[i] += (rr_intervals[x] * rr_intervals[x])
sum_rr += rr_intervals[x]
sum_rr2 += (rr_intervals[x] * rr_intervals[x])
totnn += 1
if lastann == 'N':
totnnn += 1
rmssd += (rr_intervals[x] - lastrr) * (rr_intervals[x] - lastrr)
# nndif[0] = NNDIF
if abs(rr_intervals[x] - lastrr) - 0.05 > (10 ** -10):
nnx += 1
lastann = ann[x-1]
lastrr = rr_intervals[x]
if totnn == 0:
return 0, 0, 0, 0
sdnn = np.sqrt((sum_rr2 - sum_rr * sum_rr / totnn) / (totnn - 1))
rmssd = np.sqrt(rmssd/totnnn)
pnn50 = nnx / totnnn
if nnn > 1:
ratbuf[i] = nnn / nrr
sdbuf[i] = np.sqrt((sdbuf[i] - avbuf[i] * avbuf[i] / nnn) / (nnn - 1))
avbuf[i] /= nnn
nb = i + 1
sum_rr = 0.0
sum_rr2 = 0.0
k = 0
h = 0
while k < nb:
if ratbuf[k] != 0:
h += 1
sum_rr += avbuf[k]
sum_rr2 += (avbuf[k] * avbuf[k])
k += 1
sdann = np.sqrt((sum_rr2 - sum_rr * sum_rr / h) / (h - 1))
return sdnn, sdann, rmssd, pnn50
def get_result_from_get_hrv(filename):
with open(filename, 'r') as f:
csv_reader = csv.reader(f, delimiter=',')
index = 0
for row in csv_reader:
if index > 0:
output = [s.strip() for s in row[0].split('=') if s]
# print('output = ', output)
if output[0] == 'SDNN':
sdnn = output[1]
if output[0] == 'SDANN':
sdann = output[1]
if output[0] == 'rMSSD':
rmssd = output[1]
if output[0] == 'pNN50':
pnn50 = output[1]
if output[0] == 'ULF PWR':
ulf = output[1]
if output[0] == 'VLF PWR':
vlf = output[1]
if output[0] == 'LF PWR':
lf = output[1]
if output[0] == 'HF PWR':
hf = output[1]
if output[0] == 'TOT PWR':
tp = output[1]
if output[0] == 'LF/HF':
ratio_lf_hf = output[1]
index += 1
return float(sdnn), float(sdann), float(rmssd), float(pnn50), float(ulf), float(vlf), \
float(lf), float(hf), float(tp), float(ratio_lf_hf)
def save_file():
extension = "atr"
result_all = []
file_process = ['File']
sdnn_l = ['sdnn']
sdann_l = ['sdann']
rmssd_l = ['rmssd']
pnn50_l = ['pnn50']
ulf_l = ['ulf']
vlf_l = ['vlf']
lf_l = ['lf']
hf_l = ['hf']
tp_l = ['tp']
ratio_lf_hf_l = ['ratio_lf_hf']
sdnn_l_p = ['sdnn']
sdann_l_p = ['sdann']
rmssd_l_p = ['rmssd']
pnn50_l_p = ['pnn50']
ulf_l_p = ['ulf']
vlf_l_p = ['vlf']
lf_l_p = ['lf']
hf_l_p = ['hf']
tp_l_p = ['tp']
ratio_lf_hf_l_p = ['ratio_lf_hf']
test_file = ['103', '113', '117', '121', '123', '200', '202', '210', '212', '213',
'219', '221', '213', '228', '231', '233', '234',
'101', '106', '108', '112', '114', '115', '116', '119', '122', '201', '203',
'205', '208', '209', '215', '220', '223', '230',
'105', '100']
file_dis = ['109', '111', '118', '124', '207', '214', '232']
for root, dirs, files in os.walk(DATA_PATH):
files = np.sort(files)
for name in files:
if extension in name:
if os.path.basename(name[:-4]) not in test_file:
continue
print('Processing file...', os.path.basename(name))
cur_dir = os.getcwd()
os.chdir(DATA_PATH)
os.system('rrlist {} {} -M -s >{}.rr'.format(extension, name.split('.')[0], name.split('.')[0]))
time_m = []
rr_intervals = []
ann = []
with open(name.split('.')[0] + '.rr', 'r') as rr_file:
for line in rr_file:
time_m.append(line.split(' ')[0])
rr_intervals.append(line.split(' ')[1])
ann.append(line.split(' ')[2].split('\n')[0])
time_m = np.asarray(time_m, dtype=float)
rr_intervals = np.asarray(rr_intervals, dtype=float)
sdnn, sdann, rmssd, pnn50 = time_domain(time_m, rr_intervals, ann)
if sdnn == 0 and sdann == 0 and rmssd == 0 and pnn50 == 0:
print('No result hrv')
file_dis.append(os.path.basename(name[:-4]))
continue
print('sdnn', sdnn)
print('rmssd', rmssd)
print('pnn50', pnn50)
print('sdann', sdann)
time_m = time_m - time_m[0]
time_m = np.round(time_m, 3)
time_nn = []
nn_intervals = []
for i in range(1, len(ann)):
if ann[i] == 'N' and ann[i - 1] == 'N':
nn_intervals.append(rr_intervals[i])
time_nn.append(time_m[i])
time_nn = np.asarray(time_nn, dtype=float)
nn_intervals = np.asarray(nn_intervals, dtype=float)
fc = FreqDomainClass()
ulf, vlf, lf, hf, tp, ratio_lf_hf = fc.freq_domain(time_nn, nn_intervals)
sdnn_l.append(sdnn)
sdann_l.append(sdann)
rmssd_l.append(rmssd)
pnn50_l.append(pnn50)
ulf_l.append(ulf)
vlf_l.append(vlf)
lf_l.append(lf)
hf_l.append(hf)
tp_l.append(tp)
ratio_lf_hf_l.append(ratio_lf_hf)
print('ULF PWR: ', ulf)
print('VLF PWR: ', vlf)
print('LF PWR: ', lf)
print('HF PWR: ', hf)
print('TOT PWR: ', tp)
print('LF/HF: ', ratio_lf_hf)
if os.path.exists('physionet_hrv.txt'):
os.remove('physionet_hrv.txt')
os.system('get_hrv -R ' + name.split('.')[0] + '.rr >> ' + 'physionet_hrv.txt')
sdnn, sdann, rmssd, pnn50, ulf, vlf, lf, hf, tp, ratio_lf_hf = \
get_result_from_get_hrv('physionet_hrv.txt')
file_process.append(os.path.basename(name[:-4]))
sdnn_l_p.append(sdnn)
sdann_l_p.append(sdann)
rmssd_l_p.append(rmssd)
pnn50_l_p.append(pnn50)
ulf_l_p.append(ulf)
vlf_l_p.append(vlf)
lf_l_p.append(lf)
hf_l_p.append(hf)
tp_l_p.append(tp)
ratio_lf_hf_l_p.append(ratio_lf_hf)
os.chdir(cur_dir)
result_all.append(file_process)
result_all.append(sdnn_l)
result_all.append(sdnn_l_p)
result_all.append(sdann_l)
result_all.append(sdann_l_p)
result_all.append(rmssd_l)
result_all.append(rmssd_l_p)
result_all.append(pnn50_l)
result_all.append(pnn50_l_p)
result_all.append(ulf_l)
result_all.append(ulf_l_p)
result_all.append(vlf_l)
result_all.append(vlf_l_p)
result_all.append(lf_l)
result_all.append(lf_l_p)
result_all.append(hf_l)
result_all.append(hf_l_p)
result_all.append(tp_l)
result_all.append(tp_l_p)
result_all.append(ratio_lf_hf_l)
result_all.append(ratio_lf_hf_l_p)
print(file_dis)
with open('hrv2.csv', 'w+') as f:
writer = csv.writer(f)
for values in zip_longest(*result_all):
writer.writerow(values)
def main():
extension = "atr"
for root, dirs, files in os.walk(DATA_PATH):
files = np.sort(files)
for name in files:
if extension in name:
if name not in ['101.atr']:
continue
cur_dir = os.getcwd()
os.chdir(DATA_PATH)
os.system('rrlist {} {} -M -s >{}.rr'.format(extension, name.split('.')[0], name.split('.')[0]))
time_m = []
rr_intervals = []
ann = []
with open(name.split('.')[0] + '.rr', 'r') as rr_file:
for line in rr_file:
time_m.append(line.split(' ')[0])
rr_intervals.append(line.split(' ')[1])
ann.append(line.split(' ')[2].split('\n')[0])
time_m = np.asarray(time_m, dtype=float)
rr_intervals = np.asarray(rr_intervals, dtype=float)
sdnn, sdann, rmssd, pnn50 = time_domain(time_m, rr_intervals, ann)
if sdnn == 0 and sdann == 0 and rmssd == 0 and pnn50 == 0:
print('No result hrv')
return 0
print('sdnn', sdnn)
print('rmssd', rmssd)
print('pnn50', pnn50)
print('sdann', sdann)
time_m = time_m - time_m[0]
time_m = np.round(time_m, 3)
time_nn = []
nn_intervals = []
for i in range(1, len(ann)):
if ann[i] == 'N' and ann[i - 1] == 'N':
nn_intervals.append(rr_intervals[i])
time_nn.append(time_m[i])
time_nn = np.asarray(time_nn, dtype=float)
nn_intervals = np.asarray(nn_intervals, dtype=float)
start = time.time()
fc = FreqDomainClass()
ulf, vlf, lf, hf, tp, ratio_lf_hf = fc.freq_domain(time_nn, nn_intervals)
end = time.time()
print('ULF PWR: ', ulf)
print('VLF PWR: ', vlf)
print('LF PWR: ', lf)
print('HF PWR: ', hf)
print('TOT PWR: ', tp)
print('LF/HF: ', ratio_lf_hf)
print('finish', end - start)
os.chdir(cur_dir)
I am using ode solver to solve stiff problem (since odeint function could not able to solve it). But by this way also I have some warnings and my plot get saturate at some point. Here is image What should I do? Here is the list of warnings:
DVODE-- Warning..internal T (=R1) and H (=R2) are
such that in the machine, T + H = T on the next step
(H = step size). solver will continue anyway
In above, R1 = 0.3667661010318D+00 R2 = 0.1426374862242D-16
DVODE-- Warning..internal T (=R1) and H (=R2) are
such that in the machine, T + H = T on the next step
(H = step size). solver will continue anyway
In above, R1 = 0.3667661010318D+00 R2 = 0.1426374862242D-16
DVODE-- Above warning has been issued I1 times.
it will not be issued again for this problem
In above message, I1 = 2
DVODE-- At current T (=R1), MXSTEP (=I1) steps
taken on this call before reaching TOUT
In above message, I1 = 500
In above message, R1 = 0.3667661010318D+00
My code:
import numpy as np
import matplotlib.pyplot as plt
import scipy.integrate as si
def func():
#arguments:::
w = 1./3.
xi = 2.86
phi1 = 1.645
phi2 = 2.* 1.202
gt = 10.**(-60)
Lt = (1.202*gt)/np.pi
Lin = 10.**-5
Lf = 0.49
dt = 0.0001
gin = gt*Lt/Lin
xin = (-np.log((3. - (xi**2)*Lin)/(3. - (xi**2)*Lt)) + np.log(Lin/Lt))/4.0
uin = -(np.log(Lin/Lt))/2.
state0 = [gin,xin,uin]
print state0
def eq(L, state):
g = state[0]
x = state[1]
u = state[2]
N = (-2.*g/(6.*np.pi + 5.*g))*(18./(1. - 2.*L) + 5.*np.log(1.- 2.*L) - phi1 + 6. )
B = (-(2. - N)*L) - ((g/np.pi)* (5.*np.log(1.-2.*L) - phi2 + (5.*N/40.)))
Eqs = np.zeros((3))
gdl = Eqs[0] = ((2.+N)*g)/B
xdl = Eqs[1] = -(2./(3.*(1.+w)))* (1./(1.-(xi**2)*L/3.))*(1./B)
udl = Eqs[2]= 1./B
return Eqs
ode = si.ode(eq)
# BDF method suited to stiff systems of ODEs
ode.set_integrator('vode',nsteps=500,method='bdf')
ode.set_initial_value(state0,Lin)
L = []
G = []
while ode.successful() and ode.t < Lf:
ode.integrate(ode.t + dt)
L.append(ode.t)
G.append(ode.y)
lam = np.vstack(L)
g,x,u = np.vstack(G).T
return g,x,u,lam
r= func()
L = r[3]
g = r[0]
lng = np.log10(g)
x = r[1]
u = r[2]
w = 1./3.
xi = 2.86
O_A = np.zeros(len(L))
q = np.zeros(len(L))
for i in np.arange(len(L)):
O_A[i] = xi**2*L[i]/3.
alpha = 2./ ((3.+3.*w) * (1.- (L[i]*xi**2)/3.) )
q[i] = 1./alpha - 1.
n = np.zeros(len(L)) #eta(n)
b = np.zeros(len(L))
for j in np.arange(len(L)):
n[j] =(-2.*g[j]/(6.*np.pi + 5.*g[j]))*(18./(1. - 2.*L[j]) + 5.*np.log(1.- 2.*L[j]) - 1.645 + 6. )
b[j]= (-(2. - n[j])*L[j]) - ((g[j]/np.pi)* (5.*np.log(1.-2.*L[j]) - 2.* 1.202 + ((5.*n[j])/4.)))
P = np.zeros(len(x))
for k in np.arange(len(x)):
C = (((3. - (xi**2)*L[k])/g[k])**(3./4.)) * (((2.*L[k] + (u[k]*b[k]))*xi**2) + (n[k] * (3.- L[k]*xi**2)) )
P[k] = (np.exp(3.*x[k])) * (np.exp(4.*u[k])) * C
plt.figure()
plt.plot(L,P)
plt.xlabel('Lambda ---->')
plt.ylabel('P ----->')
plt.title('lambda Vs P')
plt.show()
I've set up numpy.seterr as follows:
np.seterr(invalid='raise', over ='raise', under='raise')
And I'm getting the following error:
c = beta[j,i] + oneminusbeta[j,i]
FloatingPointError: overflow encountered in double_scalars
I've checked what beta[j,i] and oneminusbeta[j,i] are at the point of crash, and these are their values:
beta: -131.340389182
oneminusbeta: 0.0
Please note, this line of addition (beta[j,i] + oneminusbeta[j,i]) has run for thousands of lines in a loop (that performs image classification) before crashing here at this point.
How can I deal with this? Is it necessary to change the type of the numpy arrays?
This is how I've initialized them:
beta = np.empty([m,n])
oneminusbeta = np.empty([m,n])
Is it possible to cast the individual values before adding them up? Rather than changing the entire array declarations? Or is this even a serious issue? Would it be safe to simply turn off the numpy.seterr configuration and let the calculations go ahead without raising the error?
Edit
Someone suggested below, and I suspected as well, that the values being added shouldn't cause an overflow. Then how can I find out where the overflow is really happening?
This is my code:
epthreshold = 709
enthreshold = -708
f.write("weights["+str(i)+", " + str(j)+"] = math.exp(beta: " +str(beta[j,i])+ " + oneminusbeta: " + str(oneminusbeta[j,i])+")\n" )
c = beta[j,i] + oneminusbeta[j,i]
weights[i,j] = math.exp(np.clip(c, enthreshold, epthreshold))
And when I check my log file, this is the line I get:
weights[5550, 13] = math.exp(beta: -131.340389182 + oneminusbeta: 0.0)
Edit 2
Here's the rest of my code, where variables n,m and H have already been initialized to integer values:
import numba
import numpy as np
import statsmodels.api as sm
weights = np.empty([n,m])
for curr_n in range(n):
for curr_m in range(m):
weights[curr_n,curr_m] = 1.0/(n)
beta = np.empty([m,n])
oneminusbeta = np.empty([m,n])
for curr_class in range(m):
for curr_sample in range(n):
beta[curr_class,curr_sample] = 1./m
epthreshold = 709 # positive exponential threshold
enthreshold = -708
for h in range(H):
print "Boosting round %d ... " % h
z = np.empty([n,m])
for j in range(m): # computing working responses and weights, Step 2(a)(i)
for i in range(no_samples):
i_class = y[i] #get the correct class for the current sample
if h == 0:
z[i,j] = (int(j==i_class) - beta[j,i])/((beta[j,i])*(1. - beta[j,i]))
weights[i,j] = beta[j,i]*(1. - beta[j,i])
else:
if j == i_class:
z[i,j] = math.exp(np.clip(-beta[j,i],enthreshold, epthreshold))
else:
z[i,j] = -math.exp(np.clip(oneminusbeta[j,i], enthreshold, epthreshold))
f.write("weights["+str(i)+", " + str(j)+"] = math.exp(beta: " +str(beta[j,i])+ " + oneminusbeta: " + str(oneminusbeta[j,i])+")\n" )
c = beta[j,i] + oneminusbeta[j,i]
weights[i,j] = math.exp(np.clip(c, enthreshold, epthreshold))
g_h = np.zeros([1,1])
j = 0
# Calculating regression coefficients per class
# building the parameters per j class
for y1_w in zip(z.T, weights.T):
y1, w = y1_w
temp_g = sm.WLS(y1, X, w).fit() # Step 2(a)(ii)
if np.allclose(g_h,0):
g_h = temp_g.params
else:
g_h = np.c_[g_h, temp_g.params]
j = j + 1
if np.allclose(g,0):
g = g_h
else:
g = g + g_h # Step(2)(a)(iii)
# now set g(x), function coefficients according to new formula, step (2)(b)
sum_g = g.sum(axis=1)
for j in range(m):
diff = (g[:,j] - ((1./m) * sum_g))
g[:,j] = ((m-1.)/m) * diff
g_per_round[h,:,j] = g[:,j]
#Now computing beta, Step 2(c)...."
Q = 0.
e = 0.
for j in range(m):
# Calculating beta and oneminusbeta for class j
aj = 0.0
for i in range(no_samples):
i_class = y[i]
X1 = X[i].reshape(1, no_features)
g1 = g[:,j].reshape(no_features, 1)
gc = g[:,i_class].reshape(no_features, 1)
dot = 1. + float(np.dot(X1, g1)) - float(np.dot(X1,gc))
aj = dot
sum_e = 0.
a_q = []
a_q.append(0.)
for j2 in range(m): # calculating sum of e's except for all j except where j=i_class
if j2 != i_class: # g based on j2, not necessarily g1?
g2 = g[:,j2].reshape(no_features, 1)
dot1 = 1. + float(np.dot(X1, g2)) - float(np.dot(X1,gc))
e2 = math.exp(np.clip(dot1,enthreshold, epthreshold))
sum_e = sum_e + e2
a_q.append(dot1)
if (int(j==i_class) == 1):
a_q_arr = np.array(a_q)
alpha = np.array(a_q_arr[1:])
Q = mylogsumexp(f,a_q_arr, 1, 0)
sumalpha = mylogsumexp(f,alpha, 1, 0)
beta[j,i] = -Q
oneminusbeta[j,i] = sumalpha - Q
else:
alpha = a_q
alpha = np.array(alpha[1:])
a_q_arr = np.array(a_q)
Q = mylogsumexp(f,a_q_arr, 0, aj)
sumalpha = log(math.exp(np.clip(Q, enthreshold, epthreshold)) - math.exp(np.clip(aj, enthreshold, epthreshold)))
beta[j,i] = aj - Q
oneminusbeta[j,i] = sumalpha - Q
and the function mylogsumexp is:
def mylogsumexp(f, a, is_class, maxaj, axis=None, b=None):
np.seterr(over="raise", under="raise", invalid="raise")
threshold = -sys.float_info.max
maxthreshold = sys.float_info.max
epthreshold = 709 # positive exponential threshold
enthreshold = -708
a = asarray(a)
if axis is None:
a = a.ravel()
else:
a = rollaxis(a, axis)
if is_class == 1:
a_max = a.max(axis=0)
else:
a_max = maxaj
#bnone = " none "
if b is not None:
a_max = maxaj
b = asarray(b)
if axis is None:
b = b.ravel()
else:
b = rollaxis(b, axis)
a = np.clip(a - a_max, enthreshold, epthreshold)
midout = np.sum(np.exp(a), axis=0)
midout = 1.0 + np.clip(midout - math.exp(a_max), threshold, maxthreshold)
out = np.log(midout)
else:
a = np.clip(a - a_max, enthreshold, epthreshold)
out = np.log(np.sum(np.exp(a)))
out += a_max
if out == float("inf"):
out = maxthreshold
if out == float("-inf"):
out = threshold
return out