def effect_gvd(wl_um, gvd, t_fs, d_mm):
"""
Calculates the effect the group velocity dispersion has on an unchirped Gaussian pulse.
Source:
http://www.rp-photonics.com/chromatic_dispersion.html
numpy.log() is natural log
CHANGELOG:
20170315/RB: started function.
INPUT:
wl_um (ndarray): wavelengths in micron
gvd: group velocity dispersion in fs^2/mm
t: pulse durations
d: thicknesses of material
OUTPUT:
t_out (ndarray): 3D array with pulse lengths wl_um x t x d
"""
t_fs = CF.make_numpy_ndarray(t_fs)
d_mm = CF.make_numpy_ndarray(d_mm)
W, T, D = numpy.meshgrid(wl_um, t_fs, d_mm, indexing="ij")
G, dump, dump = numpy.meshgrid(gvd, t_fs, d_mm, indexing="ij")
t_out = T * numpy.sqrt(1 + (4 * numpy.log(2) * G * D / T**2)**2)
return t_out
def interpolate_two_datasets(x1, y1, x2, y2, x_step = 1, interpolation_kind = "default", verbose = 0):
"""
Take datasets 1 and 2 and unify the x-axis, interpolate the y-values of both for the new axis. The new x-axis will be only where x1 and x2 overlap.
INPUTS:
x1, x2 (ndarray, list): x-axes of the data
y1, y2 (ndarray, list): y values of the data
x_step (number): step size of the x-axis of the interpolated data
interpolation_kind (string): Specifies the kind of interpolation as a string ('linear', 'nearest', 'zero', 'slinear', 'quadratic, 'cubic', where 'slinear', 'quadratic' and 'cubic' refer to a spline interpolation of first, second or third order) or as an integer specifying the order of the spline interpolator to use. Default is 'linear'
OUTPUTS:
new_x (ndarray): new x-axis
new_y1, new_y2 (ndarray): the interpolated values of y1 and y2
"""
if interpolation_kind == "default":
interpolation_kind = "linear"
x1 = CF.make_numpy_ndarray(x1)
y1 = CF.make_numpy_ndarray(y1)
x2 = CF.make_numpy_ndarray(x2)
y2 = CF.make_numpy_ndarray(y2)
if x1[0] > x1[-1]:
x1 = x1[::-1]
y1 = y1[::-1]
if x2[0] > x2[-1]:
x2 = x2[::-1]
y2 = y2[::-1]
if x1[0] > x2[0]:
start = x1[0]
else:
start = x2[0]
if x1[-1] < x2[-1]:
finish = x1[-1]
else:
finish = x2[-1]
if verbose > 0:
print(start, finish)
new_x = numpy.arange(start, finish, step = x_step)
f = interp1d(x1, y1, kind = interpolation_kind)
new_y1 = f(new_x)
f = interp1d(x2, y2, kind = interpolation_kind)
new_y2 = f(new_x)
return new_x, new_y1, new_y2
def quadratic(A, t):
"""
sum_i A[i] * t**i
"""
A = CF.make_numpy_ndarray(A)
t = CF.make_numpy_ndarray(t)
res = 0
for i in range(len(A)):
res += A[i] * t**(i)
return res
def absorption_for_gas(ev,
absorption,
mbars,
cms,
evs=[],
interpolation_kind=""):
"""
INPUTS:
x_ev (ndarray): energies, x-axis
y_ab (ndarray): absorption, y-axis
mbars (list): list with pressures, in mbar
cms (list): list with pathlengths, in cm
evs (list): list with specific wavelengths to calculate the transmission for. If length is zero, all energies will be calculated.
OUTPUT:
ev (ndarray):
"""
mbars = CF.make_numpy_ndarray(mbars)
cms = CF.make_numpy_ndarray(cms)
evs = CF.make_numpy_ndarray(evs)
if len(evs) != 0:
y_ab = interpolate_absorption(ev=ev,
ab=absorption,
x=evs,
interpolation_kind=interpolation_kind)
x_ev = evs
n_evs = len(evs)
else:
y_ab = absorption[:]
x_ev = ev[:]
n_evs = len(y_ab)
n_mbars = len(mbars)
n_cms = len(cms)
ab = numpy.zeros((n_evs, n_mbars, n_cms))
for i in range(n_evs):
ab[i, :, :] = y_ab[i]
for i in range(n_mbars):
ab[:, i, :] *= mbars[i]
for i in range(n_cms):
ab[:, :, i] *= cms[i]
tr = 10**ab
return ev, ab, tr
def transmission_for_compound(wl_nm,
abs_mm,
R,
thickness_mms,
wl_nms=[],
interpolation_kind="default"):
"""
INPUTS:
wl_nm (ndarray): wavelength axis of the imported data
abs_mm (ndarray): pure absorption component
R (ndarray): reflection component
thickness_mms (int, list, ndarray): list with thicknesses in mm
wl_nms (int, list, ndarray): list with wavelengths of interest, can be empty, then wl_nm is used.
mms (list): list with pathlengths, in mm
l_nms (list): list with specific wavelengths to calculate the transmission for. If length is zero, all energies will be calculated.
OUTPUT:
ev (ndarray):
"""
thickness_mms = CF.make_numpy_ndarray(thickness_mms)
n_thick = len(thickness_mms)
wl_nms = CF.make_numpy_ndarray(wl_nms)
if len(wl_nms) != 0:
y_abs_mm = MATH.interpolate_data(original_x=wl_nm,
original_y=abs_mm,
new_x=wl_nms,
interpolate_kind=interpolation_kind)
R = MATH.interpolate_data(original_x=wl_nm,
original_y=R,
new_x=wl_nms,
interpolate_kind=interpolation_kind)
n_nms = len(wl_nms)
else:
y_abs_mm = abs_mm[:]
wl_nms = wl_nm[:]
n_nms = len(abs_mm)
ABS, TH = numpy.meshgrid(y_abs_mm, thickness_mms)
R, dump = numpy.meshgrid(R, thickness_mms)
_R = (1 - R)**2
transmission = 10**(-ABS * TH) * (_R)
return wl_nms, thickness_mms, transmission
def transmission_for_compound(e_ev,
tr_norm,
ums,
evs=[],
interpolation_kind="default"):
"""
INPUTS:
ev (ndarray): ev axis of the imported data
x_ev (ndarray): energies, x-axis
y_tr (ndarray): absorption, y-axis
ums (list): list with pathlengths, in um
evs (list): list with specific wavelengths to calculate the transmission for. If length is zero, all energies will be calculated.
OUTPUT:
ev (ndarray):
"""
ums = CF.make_numpy_ndarray(ums)
evs = CF.make_numpy_ndarray(evs)
if len(evs) != 0:
y_tr = MATH.interpolate_data(original_x=ev,
original_y=transmission,
new_x=evs,
interpolate_kind=interpolation_kind)
x_ev = evs
n_evs = len(evs)
else:
y_tr = transmission[:]
x_ev = ev[:]
n_evs = len(y_tr)
n_ums = len(ums)
tr = numpy.zeros((n_evs, n_ums))
for i in range(n_evs):
tr[i, :] = y_tr[i]
ab = numpy.log10(tr)
for i in range(n_ums):
ab[:, i] *= ums[i]
tr = 10**ab
return ev, tr
def rb_cos(A, t):
"""
4 parameters
function: A[0] + A[1] * numpy.cos(2 * numpy.pi * A[2] * t + A[3])
A[0]: offset
A[1]: amplitude
A[2]: frequency
A[3]: phase
"""
A = CF.make_numpy_ndarray(A)
if len(A) != 4:
raise IndexError("rb_cos(): you should enter 4 parameters in list A.")
t = CF.make_numpy_ndarray(t)
return A[0] + A[1] * numpy.cos(2 * numpy.pi * A[2] * t + numpy.pi * A[3])
def reflectance(n1, n2, a_deg=[], a_range=(0, 90), n_steps=-1):
"""
It is calculated for what?
- a_deg > a_range
"""
n1 = CF.make_numpy_ndarray(n1)
n2 = CF.make_numpy_ndarray(n2)
a_deg = CF.make_numpy_ndarray(a_deg)
if len(a_deg) == 0:
if n_steps == -1:
n_steps = int(a_range[1] - a_range[0]) + 1
if n_steps < 5:
n_steps = 5
a_deg = numpy.linspace(a_range[0], a_range[1], num=n_steps)
a_rad = a_deg * numpy.pi / 180
N1, A = numpy.meshgrid(n1, a_rad)
N2, A = numpy.meshgrid(n2, a_rad)
# when n2 > n1, there is a critical angle. Here angles > critical angles are set to nan.
temp = ((N1 * numpy.sin(A)) / (N2))**2
numpy.putmask(temp, temp >= 1, numpy.nan)
x = numpy.sqrt(1 - temp)
a = N1 * numpy.cos(A)
b = N2 * x
Rs = numpy.abs((a - b) / (a + b))**2
a = N1 * x
b = N2 * numpy.cos(A)
Rp = numpy.abs((a - b) / (a + b))**2
return a_deg, Rs, Rp
def n_k_for_wavelengths(db_record,
wl_um,
interpolate_kind="default",
verbose=0):
"""
Calculate the refractive index and extinction coefficient for wavelengths wl_um. The input is the data from refractiveindex.info and comes as one of 9 equations (not all of them are implemented) or as a table of values. For the latter interpolation will be used to get the values for the asked wavelengths.
db_record is the dictionary.
"""
if "type" not in db_record:
raise KeyError(
"ri_for_wavelengths(): The database record does not have a key 'type'."
)
wl_um = CF.make_numpy_ndarray(wl_um)
if db_record["type"] == "tabulated nk":
if wl_um[0] < db_record["data"][:, 0][0]:
raise ValueError(
"Error, wavelength %1.2f micron is too low! It should be above %1.2f micron."
% (wl_um[0], db_record["data"][:, 0][0]))
elif wl_um[-1] > db_record["data"][:, 0][-1]:
raise ValueError(
"Error, wavelength %1.2f micron is too high! It should be below %1.2f micron."
% (wl_um[-1], db_record["data"][:, 0][-1]))
DEBUG.verbose(" Tabulated data (type nk)", verbose_level=1)
n = MATH.interpolate_data(db_record["data"][:, 0],
db_record["data"][:, 1], wl_um)
k = MATH.interpolate_data(db_record["data"][:, 0],
db_record["data"][:, 2], wl_um)
else:
raise NotImplementedError(
"Importing n and k are only implemented for tabulated records.")
return n, k
def make_coordinates(inch_per_unit, x_units, y_units, left, bottom, width,
height, flag_verbose = False):
"""
matplotlib.figure.add_axes() requires coordinates (left, bottom, width,
height) for each axes instance. The values are between 0 and 1. There are
two problems.
First is that the aspect ratio may be off. If the figure is a rectangle and
the subplot is 0.5 wide and 0.5 high, the subplot is also a rectangle.
Second is that if the figure size changes all the carefully planned margins
are lost.
This function works with units. The x-axis is x_units long. Each unit has a
defined length inch_per_unit. The left edges are at [left]. This solves the
two problems. If your plot is N units wide and N units high, it will be a
square. When you resize the figure (change x_units) the margins, which are
in units, will remain the same.
INPUT:
- inch_per_unit (number): used to scale to inches
- x_units, y_units (number): width and height of the figure, in units
- left, bottom, width, height (numpy.ndarray with ints and/or floats, also
accepts list or int or float): the positions of the axes. The longest list
determines the number of plots. Shorter lists are cycled.
OUTPUT:
- figsize: tuple that is accepted by plt.figure(figsize = figsize)
- coords, a list with tuples with (l,b,w,h). The tuples are accepted by
fig.add_axes((l,b,w,h)).
EXAMPLE 1:
Three plots next to each other.
01234567
1 x x x
0xxxxxxx
x_units = 8
y_units = 3
left = [1,3,6] #
bottom = 1 # [1], [1,1], [1,1,1]
# not [1,1,1,1], that gives extra subplot
width = [1,2] # [1,2,1]
height = 1 # [1], [1,1], [1,1,1]
EXAMPLE 2:
Four equally sized and spaced plots.
01234
3 x x
2xxxx
1 x x
0xxxx
inch_per_unit = 1.0
x_units = 5
y_units = 5
left = [1,3] # [1,3,1,3]
# not [1,3,1], that would give: [1,3,1,1]
bottom = [3,3,1,1] #
width = 1 # [1], [1,1], [1,1,1], [1,1,1,1]
height = 1 # [1], [1,1], [1,1,1], [1,1,1,1]
EXAMPLE 3:
A complex arrangement. All coordinates are explicitly given.
01234567
6 x x
5 x x
4xxxx x
3 xxxxx
2 x x
1 x x
0xxxxxxx
x_units = 8
y_units = 8
left = [1,5,1,4]
bottom = [5,4,1,1]
width = [3,2,2,3]
height = [2,3,3,2]
CHANGELOG:
20130317/RB: started
"""
# calculate figure size
figsize = (x_units * inch_per_unit, y_units * inch_per_unit)
# change all values to values between 0 and 1
left = CF.make_numpy_ndarray(left) / x_units
bottom = CF.make_numpy_ndarray(bottom) / y_units
width = CF.make_numpy_ndarray(width) / x_units
height = CF.make_numpy_ndarray(height) / y_units
# find longest list, determines number of sub plots
N = find_longest_list(left, bottom, width, height)
# determine the coordinates
coords = []
for i in range(N):
l = left[i % len(left)]
b = bottom[i % len(bottom)]
w = width[i % len(width)]
h = height[i % len(height)]
coords.append((l,b,w,h))
return figsize, coords
def test_dict(self):
result = CF.make_numpy_ndarray({"a": 1, "b": 2})
def test_list_1(self):
result = CF.make_numpy_ndarray([1,2])
self.assertEqual(type(result), numpy.ndarray)
self.assertTrue(numpy.all(numpy.array([1,2]) == result))
def test_string_2(self):
result = CF.make_numpy_ndarray(["fiets", "auto"])
self.assertEqual(type(result), numpy.ndarray)
self.assertTrue(numpy.all(numpy.array(["fiets", "auto"]) == result))
def test_string_1(self):
result = CF.make_numpy_ndarray("fiets")
self.assertEqual(type(result), numpy.ndarray)
self.assertEqual(result, ["fiets"])
self.assertTrue(result[0] == "fiets")
def test_float_1(self):
result = CF.make_numpy_ndarray(1)
self.assertEqual(type(result), numpy.ndarray)
self.assertEqual(result, numpy.array(1))
def ri_for_wavelengths(db_record,
wl_um,
interpolate_kind="default",
verbose=0):
"""
Calculate the refractive index for wavelengths wl_um. The input is the data from refractiveindex.info and comes as one of 9 equations (not all of them are implemented) or as a table of values. For the latter interpolation will be used to get the values for the asked wavelengths.
db_record is the dictionary.
"""
if "type" not in db_record:
raise KeyError(
"ri_for_wavelengths(): The database record does not have a key 'type'."
)
wl_um = CF.make_numpy_ndarray(wl_um)
error_string = "Calculation of the refractive index is not implemented for "
# check the range
if "formula" in db_record["type"]:
# temp = numpy.where(wl_um < db_record["range"][0])[0]
# print(temp)
# wl_um[temp] = numpy.nan
#
# temp = numpy.where(wl_um > db_record["range"][1])[0]
# print(temp)
# wl_um[temp] = numpy.nan
print(db_record["range"][0])
if wl_um[0] < db_record["range"][0]:
raise ValueError(
"Error, wavelength %1.2f micron is too low! It should be above %1.2f micron."
% (wl_um[0], db_record["range"][0]))
elif wl_um[-1] > db_record["range"][1]:
raise ValueError(
"Error, wavelength %1.2f micron is too high! It should be below %1.2f micron."
% (wl_um[-1], db_record["range"][-1]))
if "tabulated" in db_record["type"]:
if wl_um[0] < db_record["data"][:, 0][0]:
raise ValueError(
"Error, wavelength %1.2f micron is too low! It should be above %1.2f micron."
% (wl_um[0], db_record["data"][:, 0][0]))
elif wl_um[-1] > db_record["data"][:, 0][-1]:
raise ValueError(
"Error, wavelength %1.2f micron is too high! It should be below %1.2f micron."
% (wl_um[-1], db_record["data"][:, 0][-1]))
if db_record["type"] == "formula 1":
DEBUG.verbose(" Using formula 1 to calculate refractive indices",
verbose_level=1)
n_terms = int(len(db_record["coefficients"]) / 2 - 0.5)
ri = numpy.ones(len(wl_um)) + db_record["coefficients"][0]
l = wl_um**2
for i in range(n_terms):
ri += (db_record["coefficients"][2 * i + 1] *
l) / (l - db_record["coefficients"][2 * i + 2]**2)
ri = numpy.sqrt(ri)
if verbose >= 1:
for i in range(len(wl_um)):
print(i, wl_um[i], ri[i])
elif db_record["type"] == "formula 2":
DEBUG.verbose(" Using formula 2 to calculate refractive indices",
verbose_level=1)
n_terms = int(len(db_record["coefficients"]) / 2 - 0.5)
ri = numpy.ones(len(wl_um)) + db_record["coefficients"][0]
l = wl_um**2
for i in range(n_terms):
ri += (db_record["coefficients"][2 * i + 1] *
l) / (l - db_record["coefficients"][2 * i + 2])
ri = numpy.sqrt(ri)
if verbose >= 1:
for i in range(len(wl_um)):
print(i, wl_um[i], ri[i])
elif db_record["type"] == "formula 3":
DEBUG.verbose(" Using formula 3 to calculate refractive indices",
verbose_level=1)
n_terms = int(len(db_record["coefficients"]) / 2 - 0.5)
ri = numpy.zeros(len(wl_um)) + db_record["coefficients"][0]
for i in range(n_terms):
ri += db_record["coefficients"][
2 * i + 1] * wl_um**db_record["coefficients"][2 * i + 2]
ri = numpy.sqrt(ri)
if verbose >= 1:
for i in range(len(wl_um)):
print(i, wl_um[i], ri[i])
elif db_record["type"] == "formula 4":
DEBUG.verbose(" Using formula 4 to calculate refractive indices",
verbose_level=1)
ri = numpy.zeros(len(wl_um)) + db_record["coefficients"][0]
n_coeff = len(db_record["coefficients"])
if n_coeff >= 5:
ri += (db_record["coefficients"][1] *
wl_um**db_record["coefficients"][2]) / (
wl_um**2 - db_record["coefficients"][3]**
db_record["coefficients"][4])
if n_coeff >= 9:
ri += (db_record["coefficients"][5] *
wl_um**db_record["coefficients"][6]) / (
wl_um**2 - db_record["coefficients"][7]**
db_record["coefficients"][8])
n_terms = int((len(db_record["coefficients"]) - 9) / 2)
for i in range(n_terms):
ri += db_record["coefficients"][
2 * i + 9] * wl_um**db_record["coefficients"][2 * i + 10]
ri = numpy.sqrt(ri)
if verbose >= 1:
for i in range(len(wl_um)):
print(i, wl_um[i], ri[i])
elif db_record["type"] == "formula 5":
DEBUG.verbose(" Using formula 5 to calculate refractive indices",
verbose_level=1)
n_terms = int(len(db_record["coefficients"]) / 2 - 0.5)
ri = numpy.zeros(len(wl_um)) + db_record["coefficients"][0]
for i in range(n_terms):
ri += db_record["coefficients"][
2 * i + 1] * wl_um**db_record["coefficients"][2 * i + 2]
if verbose >= 1:
for i in range(len(wl_um)):
print(i, wl_um[i], ri[i])
elif db_record["type"] == "formula 6":
DEBUG.verbose(" Using formula 6 to calculate refractive indices",
verbose_level=1)
n_terms = int(len(db_record["coefficients"]) / 2 - 0.5)
ri = numpy.ones(len(wl_um)) + db_record["coefficients"][0]
l = wl_um**-2
for i in range(n_terms):
ri += (db_record["coefficients"][2 * i + 1]) / (
db_record["coefficients"][2 * i + 2] - l)
if verbose >= 1:
for i in range(len(wl_um)):
print(i, wl_um[i], ri[i])
elif db_record["type"] == "formula 7":
DEBUG.verbose(" Using formula 7 to calculate refractive indices",
verbose_level=1)
l = wl_um**2
n_terms = len(db_record["coefficients"]) - 3
t1 = db_record["coefficients"][1] / (l - 0.028)
t2 = db_record["coefficients"][2] * (1 / (l - 0.028))**2
ri = db_record["coefficients"][0] + t1 + t2
for i in range(n_terms):
ri += db_record["coefficients"][i + 3] * l**(i + 1)
if verbose >= 1:
for i in range(len(wl_um)):
print(i, wl_um[i], ri[i])
elif db_record["type"] == "formula 8":
raise NotImplementedError(error_string + "formula 8")
elif db_record["type"] == "formula 9":
raise NotImplementedError(error_string + "formula 9")
elif db_record["type"] == "tabulated n":
DEBUG.verbose(" Tabulated data (type n)", verbose_level=1)
ri = MATH.interpolate_data(db_record["data"][:, 0],
db_record["data"][:, 1], wl_um)
elif db_record["type"] == "tabulated nk":
DEBUG.verbose(" Tabulated data (type nk)", verbose_level=1)
ri = MATH.interpolate_data(db_record["data"][:, 0],
db_record["data"][:, 1], wl_um)
else:
raise ValueError(
"The type of data in the database record is unknown (usually formula 1-9 or tabulated data). Type here is %s."
% db_record["type"])
return ri
def gvd_for_wavelengths(db_record,
wl_um,
interpolate_kind="default",
verbose=0):
"""
Calculate the GVD for wavelengths wl_um. The GVD is calculated as the second derivative of the refractive index with respect to the wavelength. The input is the data from refractiveindex.info and comes as one of 9 equations (not all of them are implemented) or as a table of values.
For the equations, the second derivatives were calculated using WolframAlpha.
"""
if "type" not in db_record:
raise KeyError(
"gvd_for_wavelengths: The database record does not have a key 'type'."
)
wl_um = CF.make_numpy_ndarray(wl_um)
error_string = "GVD is not implemented for "
# check the range
if "formula" in db_record["type"]:
if wl_um[0] < db_record["range"][0]:
raise ValueError(
"Error, wavelength %1.2f micron is too low! It should be above %1.2f micron."
% (wl_um[0], db_record["range"][0]))
elif wl_um[-1] > db_record["range"][1]:
raise ValueError(
"Error, wavelength %1.2f micron is too high! It should be below %1.2f micron."
% (wl_um[-1], db_record["range"][-1]))
if "tabulated" in db_record["type"]:
raise NotImplementedError(
"GVD can't be calculated for tabulated data.")
if db_record["type"] == "formula 1":
DEBUG.verbose(
" Using formula 1 to calculate group velocity dispersion",
verbose_level=1)
gvd = EQ.gvd_formula_1(wl_um, db_record["coefficients"])
gvd = (1e21 * gvd * wl_um**3) / (2 * numpy.pi * (CONST.c_ms)**2)
elif db_record["type"] == "formula 2":
"""
Formula 2 is the same as formula 1, but some given coefficients are already squared. The square root of these coefficients is taken and the GVD equation for formula 1 is used.
"""
DEBUG.verbose(
" Using formula 2 to calculate group velocity dispersion",
verbose_level=1)
s = numpy.copy(db_record["coefficients"])
for i in range(len(s)):
if i > 0 and i % 2 == 0:
s[i] = numpy.sqrt(s[i])
gvd = EQ.gvd_formula_1(wl_um, s)
gvd = (1e21 * gvd * wl_um**3) / (2 * numpy.pi * (CONST.c_ms)**2)
elif db_record["type"] == "formula 3":
DEBUG.verbose(
" Using formula 3 to calculate group velocity dispersion",
verbose_level=1)
gvd = EQ.gvd_formula_3(wl_um, db_record["coefficients"])
gvd = (1e21 * gvd * wl_um**3) / (2 * numpy.pi * (CONST.c_ms)**2)
elif db_record["type"] == "formula 4":
DEBUG.verbose(
" Using formula 4 to calculate group velocity dispersion",
verbose_level=1)
gvd = EQ.gvd_formula_4(wl_um, db_record["coefficients"])
gvd = (1e21 * gvd * wl_um**3) / (2 * numpy.pi * (CONST.c_ms)**2)
elif db_record["type"] == "formula 5":
DEBUG.verbose(
" Using formula 5 to calculate group velocity dispersion",
verbose_level=1)
gvd = EQ.gvd_formula_5(wl_um, db_record["coefficients"])
gvd = (1e21 * gvd * wl_um**3) / (2 * numpy.pi * (CONST.c_ms)**2)
elif db_record["type"] == "formula 6":
DEBUG.verbose(
" Using formula 6 to calculate group velocity dispersion",
verbose_level=1)
gvd = EQ.gvd_formula_6(wl_um, db_record["coefficients"])
gvd = (1e21 * gvd * wl_um**3) / (2 * numpy.pi * (CONST.c_ms)**2)
elif db_record["type"] == "formula 7":
DEBUG.verbose(
" Using formula 7 to calculate group velocity dispersion",
verbose_level=1)
gvd = EQ.gvd_formula_7(wl_um, db_record["coefficients"])
gvd = (1e21 * gvd * wl_um**3) / (2 * numpy.pi * (CONST.c_ms)**2)
elif db_record["type"] == "formula 8":
raise NotImplementedError(error_string + "formula 8")
elif db_record["type"] == "formula 9":
raise NotImplementedError(error_string + "formula 9")
else:
raise ValueError(
"The type of data in the database record is unknown (usually formula 1-9). Type here is %s."
% db_record["type"])
return wl_um, gvd