def powerMethodGPU(intFrog, itr = 1): ''' Extracts the pulse and gate as functions of time from the FROG with the power method ''' nbrPoints = shape(intFrog)[0] tn = linspace(-nbrPoints/2, nbrPoints/2, nbrPoints) U0 = (pulse.gaussianPulse(tn, nbrPoints/2, 1.0) * (1 + 0.4*rand(nbrPoints))).real for i in arange(itr): U0A = array(matrix(intFrog)*matrix(U0).T) U0 = U0A.T/(la.norm(U0A)) return U0
def powerMethodGPU(intFrog, itr=1):
'''
Extracts the pulse and gate as functions of time from the FROG
with the power method
'''
nbrPoints = shape(intFrog)[0]
tn = linspace(-nbrPoints / 2, nbrPoints / 2, nbrPoints)
U0 = (pulse.gaussianPulse(tn, nbrPoints / 2, 1.0) *
(1 + 0.4 * rand(nbrPoints))).real
for i in arange(itr):
U0A = array(matrix(intFrog) * matrix(U0).T)
U0 = U0A.T / (la.norm(U0A))
return U0
def bandPassFilter(t, SVEAAmp, lambdaZero, filterBW, apodisation = 1.0): ''' Bandpass Filter ''' C = 2.99792458e-4 T = t.max()-t.min() nt = len(t) dt = t[1]-t[0] w = wspace(T,nt) vs = fftshift(w/(2*pi)) wavelength = (1/((vs/C)+1/(lambdaZero*1E-9)))*1e9 spectrumAmp = fftshift(fftpack.fft(SVEAAmp)) filterEnv=pulse.gaussianPulse(wavelength, filterBW, lambdaZero, 1.0, apodisation) return [wavelength, fftpack.ifft(spectrumAmp*filterEnv)]
def spectrogram(t, eFieldSVEA, lambdaZero=0.0):
'''
Compute the spectrogram of a SVEA pulse
'''
nt = len(t)
tn = linspace(-nt / 2, nt / 2, nt)
gateFunc = pulse.gaussianPulse(tn, 20.0, 0.0, 1.0, 12)
[w, U] = pulseSpectrum(t, eFieldSVEA, lambdaZero, units='nm')
nbPoints = len(eFieldSVEA)
ampFrog = matrix(eFieldSVEA).T * matrix(gateFunc)
for i in arange(1, nbPoints):
ampFrog[:, i] = roll(ampFrog[:, i], (nbPoints / 2) - i, axis=0)
ampFrog = fftpack.fftshift(fftpack.ifft(fftpack.ifftshift(ampFrog)))
intFrog = pow(abs(ampFrog), 2)
return [w, ampFrog]
def spectrogram(t, eFieldSVEA, lambdaZero = 0.0): ''' Compute the spectrogram of a SVEA pulse ''' nt = len(t) tn = linspace(-nt/2,nt/2, nt) gateFunc = pulse.gaussianPulse(tn, 20.0, 0.0, 1.0, 12) [w, U] = pulseSpectrum(t, eFieldSVEA, lambdaZero, units='nm') nbPoints = len(eFieldSVEA) ampFrog = matrix(eFieldSVEA).T*matrix(gateFunc) for i in arange(1,nbPoints): ampFrog[:,i] = roll(ampFrog[:,i], (nbPoints/2)-i, axis=0) ampFrog = fftpack.fftshift(fftpack.ifft(fftpack.ifftshift(ampFrog))) intFrog = pow(abs(ampFrog),2) return [w,ampFrog]
def extractFrogGPU(intFrog,
epsTol=1E-5,
iterMax=1000,
method='svd',
showGraph=1):
'''
Reconstruct the phase with the svd (default) or power method
'''
nbrPoints = shape(intFrog)[0]
tn = linspace(-nbrPoints / 2, nbrPoints / 2, nbrPoints)
epsArchive = zeros(iterMax, float)
# Generate the seed
pulseSeed = pulse.gaussianPulse(tn, nbrPoints / 2,
1.0) * (1 + 0.4 * rand(nbrPoints))
gateSeed = pulse.gaussianPulse(tn, nbrPoints / 2,
1.0) * (1 + 0.4 * rand(nbrPoints))
# Normalise the input FROG trace
intFrog = normalise(intFrog)
# Generate a new FROG trace from the seed
[intFrogR, ampFrogR] = genFrog(pulseSeed, gateSeed)
intFrogR = normalise(intFrogR)
# Find chi^2 error
eps = chi2(intFrog, intFrogR)
epsArchive[0] = eps
itr = 0
# Plot init (very slow !)
if showGraph:
plt.ion()
fig = plt.figure(figsize=(12, 7))
ax = fig.add_subplot(231)
line1, line2, = pl.plot(tn, pow(abs(pulseSeed), 2), tn,
pow(abs(gateSeed), 2))
ax2 = fig.add_subplot(232)
image1 = pl.imshow(intFrogR, interpolation="nearest", aspect="normal")
ax2.set_title("Reconstructed frog trace")
ax2c = fig.add_subplot(233)
image2 = pl.imshow(intFrog, interpolation="nearest", aspect="normal")
image2.set_array(intFrog)
ax2c.set_title("Measure frog trace")
while (eps > epsTol) & (itr < iterMax):
itr = itr + 1
# Find any zero amplitudes
intFrogR[where(intFrogR == 0)] = NaN
# Normalise amplitudes (keep phase information)
ampFrogR = ampFrogR * (sqrt(intFrog / intFrogR))
# Remove divide by zeros
ampFrogR[where(isnan(intFrogR))] = 0.0
# Compute the next guest
[pulseSeed, gateSeed] = {
'svd': lambda: svdFrog(ampFrogR),
'pwm': lambda: pwmFrogGPU(ampFrogR),
}[method]()
# Make a FROG trace from new fields
[intFrogR, ampFrogR] = genFrog(pulseSeed, gateSeed)
intFrogR = normalise(intFrogR)
eps = chi2(intFrog, intFrogR)
epsArchive[itr - 1] = eps
# Update plot
if showGraph:
p_Int = pow(abs(pulseSeed), 2)
g_Int = pow(abs(gateSeed), 2)
maxValue = array([g_Int.max(), p_Int.max()]).max()
ax.set_ylim((0, maxValue))
line1.set_ydata(pow(abs(pulseSeed), 2))
line2.set_ydata(pow(abs(gateSeed), 2))
image1.set_array(intFrogR)
image1.autoscale()
ax.set_title("Error: " + str(eps))
pl.draw()
gateSeed = normalise(gateSeed)
pulseSeed = normalise(pulseSeed)
return [pulseSeed, gateSeed, epsArchive, itr]
def extractFrogGPU(intFrog, epsTol = 1E-5, iterMax = 1000, method='svd', showGraph = 1):
'''
Reconstruct the phase with the svd (default) or power method
'''
nbrPoints = shape(intFrog)[0]
tn = linspace(-nbrPoints/2, nbrPoints/2, nbrPoints)
epsArchive = zeros(iterMax, float)
# Generate the seed
pulseSeed = pulse.gaussianPulse(tn, nbrPoints/2, 1.0) * (1 + 0.4*rand(nbrPoints))
gateSeed = pulse.gaussianPulse(tn, nbrPoints/2, 1.0) * (1 + 0.4*rand(nbrPoints))
# Normalise the input FROG trace
intFrog = normalise(intFrog)
# Generate a new FROG trace from the seed
[intFrogR, ampFrogR] = genFrog(pulseSeed, gateSeed)
intFrogR = normalise(intFrogR)
# Find chi^2 error
eps = chi2(intFrog, intFrogR)
epsArchive[0] = eps
itr = 0
# Plot init (very slow !)
if showGraph:
plt.ion()
fig = plt.figure(figsize=(12,7))
ax = fig.add_subplot(231)
line1, line2, = pl.plot(tn, pow(abs(pulseSeed),2), tn, pow(abs(gateSeed),2))
ax2 = fig.add_subplot(232)
image1 = pl.imshow(intFrogR, interpolation="nearest", aspect="normal")
ax2.set_title("Reconstructed frog trace")
ax2c = fig.add_subplot(233)
image2 = pl.imshow(intFrog, interpolation="nearest", aspect="normal")
image2.set_array(intFrog)
ax2c.set_title("Measure frog trace")
while (eps>epsTol) & (itr<iterMax):
itr = itr+1
# Find any zero amplitudes
intFrogR[ where(intFrogR == 0) ] = NaN
# Normalise amplitudes (keep phase information)
ampFrogR = ampFrogR*(sqrt(intFrog/intFrogR))
# Remove divide by zeros
ampFrogR[where(isnan(intFrogR))] = 0.0
# Compute the next guest
[pulseSeed, gateSeed] = {
'svd': lambda: svdFrog(ampFrogR),
'pwm': lambda: pwmFrogGPU(ampFrogR),
}[method]()
# Make a FROG trace from new fields
[intFrogR, ampFrogR] = genFrog(pulseSeed, gateSeed)
intFrogR = normalise(intFrogR)
eps = chi2(intFrog, intFrogR)
epsArchive[itr-1] = eps
# Update plot
if showGraph:
p_Int = pow(abs(pulseSeed),2)
g_Int = pow(abs(gateSeed),2)
maxValue = array([g_Int.max(), p_Int.max()]).max()
ax.set_ylim((0,maxValue))
line1.set_ydata(pow(abs(pulseSeed),2))
line2.set_ydata(pow(abs(gateSeed),2))
image1.set_array(intFrogR)
image1.autoscale()
ax.set_title("Error: " + str(eps))
pl.draw()
gateSeed = normalise(gateSeed)
pulseSeed = normalise(pulseSeed)
return [pulseSeed, gateSeed, epsArchive, itr]
