Hi
The author of the program gives the way to run it
DiodeModel.py [-h] [-c] [-p] [-IS IS] [-N N] [-RS RS] [-m MAXIT] [-n
NPOINTS] [-s] [-f [FITFILE]] filename
These are program launch options and arguments: [-h] [-c] [-p] [-IS IS] [-N
N] [-RS RS] [-m MAXIT] [-n NPOINTS] [-s] [-f [FITFILE]] filename
DiodeModel.py dioda.txt.
I'm trying to run a program with the "diode.txt" argument but I see the
message "syntax error".
What is the cause of the error?
Best regards
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#!/usr/bin/env python3
import numpy as np
import matplotlib.pyplot as plt
import argparse
from scipy.optimize import curve_fit
from scipy.special import lambertw
def func(VS, IS, N, RS):
#Define model for diode (see wikipedia article)
VT = 26e-3
w = lambertw((IS * RS /(N * VT)) * np.exp((VS + IS * RS) / (N * VT)))
Current = np.log10((IS * ((w * N * VT / (RS * IS)) - 1) * 1000))
return Current.real
def plot(xdata, ydata, nPoints, IS, N, RS):
#generate a points to plot
vMin = xdata[0]
vMax = xdata[len(xdata) - 1],
vRange = vMax - vMin
vMin = vMin - 0.1 * vRange
vMax = vMax + 0.1 * vRange
vStep = (vMax - vMin) / (nPoints - 1)
VS = []
ID = []
for i in range(0, nPoints):
voltage = vMin + i * vStep
current = func(voltage, IS, N, RS)
VS.append(voltage)
ID.append(10**current)
#Plot the data and model
plt.figure().canvas.set_window_title('Plot Window')
plt.semilogy(xdata, ydata, 'r*', VS, ID, 'b-')
plt.ylabel('Current / mA')
plt.xlabel('Voltage / V')
plt.title('Diode I-V Characteristic')
plt.show()
def main():
#set up parser for command line args
parser = argparse.ArgumentParser(prog='DiodeModel.py')
parser.add_argument('filename', help='Name of file containing I-V data (I in mA, V in volts)')
parser.add_argument('-c', '--convert', help='Convert read in current to mA', action="store_true")
parser.add_argument('-p', '--plot', help='Just plot the data and initial guess, no fitting performed', action="store_true")
parser.add_argument('-IS', '--IS', type=float, default=1e-14, help='Initial guess at saturation current (default = 1e-14 A')
parser.add_argument('-N', '--N', type=float, default=1, help='Initial guess at Emission coefficient (default = 1)')
parser.add_argument('-RS', '--RS', type=float, default=10, help='Initial guess at ohmic resistance (default = 10 ohm)')
parser.add_argument('-m', '--maxit', type=int, default=1000, help='Maximum number of iterations (default = 1000)')
parser.add_argument('-n', '--npoints', type=int, default=250, help='Number of points in plot (default = 250)')
parser.add_argument('-s', '--save', help='Save fit parameters to file', action="store_true")
parser.add_argument('-f', '--fitfile', type=str, default="", nargs='?', help='Load fit parameters from specified file')
args = parser.parse_args()
#Read in data from file (V in volt, I in milliamp)
xdata, ydata = np.loadtxt(args.filename, unpack=True)
if args.convert: #Data is in A convert to mA
ydata = ydata * 1000
logydata = np.log10(ydata) #log of current to produce stable fit
#Set up initial guess
params = dict(IS = args.IS, N = args.N, RS = args.RS)
#Check if input file is given
if args.fitfile is None: #Use default filename
fitFile = args.filename.split('.')[0] + ".fit"
try:
fh = open(fitFile, 'r')
for line in fh:
name = line.split('=')[0].strip()
value = float(line.split('=')[1].strip())
params[name] = value
fh.close()
except IOError as e:
print("I/O error({0}): {1}".format(e.errno, e.strerror))
elif len(args.fitfile) > 0: #Use input filename
fitFile = args.fitfile
try:
fh = open(fitFile, 'r')
for line in fh:
name = line.split('=')[0].strip()
value = float(line.split('=')[1].strip())
params[name] = value
fh.close()
except IOError as e:
print("I/O error({0}): {1}".format(e.errno, e.strerror))
if args.plot:
try:
#Plot data and initial guess
print("Plotting characteristic with following parameters" +
"\nIS = " + str(params['IS']) + "\nN = " + str(params['N']) + "\nRS = " + str(params['RS']))
plot(xdata, ydata, args.npoints, params['IS'], params['N'], params['RS'])
except:
print("Plotting error")
exit()
else:
#Perform non-linear least squares fit
try:
popt, pcov, infodict, errmsg, ier = curve_fit(
func, xdata, logydata, p0=(params['IS'], params['N'], params['RS']), maxfev = args.maxit, full_output = True)
#Print converged fit parameters
print("Fit converged in " + str(infodict['nfev']) + " iterations with the following parameters")
printString = "IS = " + str(popt[0]) + "\nN = " + str(popt[1]) + "\nRS = " + str(popt[2])
print(printString)
#Output parameters to file
if args.save:
print("\nWriting fit parameters to file")
outFile = args.filename.split('.')[0] + ".fit"
try:
fh = open(outFile,"w")
fh.write(printString)
fh.close()
except IOError as e:
print("I/O error({0}): {1}".format(e.errno, e.strerror))
#generate a plot of the fit
plot(xdata, ydata, args.npoints, popt[0], popt[1], popt[2])
except RuntimeError:
print("Error - Fit did not converge, try adjusting the starting guess")
print(errmsg)
if __name__ == "__main__":
main()
