Make most modules lazy load

skrf/__init__.py

@@ -4,9 +4,9 @@
 """
 
 __version__ = '1.1.0'
-## Import all module names for coherent reference of name-space
-#import io
 
+## Import all module names for coherent reference of name-space
+# import io
 
 from . import (
  calibration,
@@ -56,9 +56,11 @@
 except Exception:
  pass
 
+
 def __getattr__(name: str):
  return getattr(instances._instances, name)
 
+
 ## built-in imports
 from copy import deepcopy as copy
 
@@ -89,14 +91,15 @@ def setup_pylab() -> bool:
 
 
 def setup_plotting():
- plotting_environment = os.environ.get('SKRF_PLOT_ENV', "pylab").lower()
+ plotting_environment = os.environ.get("SKRF_PLOT_ENV", "pylab").lower()
 
  if plotting_environment == "pylab":
  setup_pylab()
  elif plotting_environment == "pylab-skrf-style":
  if setup_pylab():
  stylely()
  # elif some different plotting environment
- # set that up
+ # set that up
+
 
 plotting_available = setup_plotting()

skrf/calibration/calibration.py

@@ -86,6 +86,15 @@
  convert_pnacoefs_2_skrf
 
 """
+from __future__ import annotations
+
+from typing import TYPE_CHECKING, TypeVar
+
+if TYPE_CHECKING:
+ try:
+ from matplotlib.pyplot import Axes
+ except ImportError:
+ Axes = TypeVar("Axes")
 
 import json
 import warnings
@@ -99,7 +108,6 @@
 import numpy as np
 from numpy import angle, einsum, exp, imag, invert, linalg, ones, poly1d, real, sqrt, zeros
 from numpy.linalg import det
-from scipy.optimize import least_squares
 
 from .. import __version__ as skrf__version__
 from .. import util
@@ -119,6 +127,7 @@
  zipfile,
 )
 from ..networkSet import NetworkSet
+from ..plotting import axes_kwarg
 
 ComplexArray = np.typing.NDArray[complex]
 
@@ -975,8 +984,8 @@ def write(self, file=None, *args, **kwargs):
 
  write(file,self, *args, **kwargs)
 
- @util.axes_kwarg
- def plot_calibration_errors(self, *args, ax: util.Axes = None, **kwargs):
+ @axes_kwarg
+ def plot_calibration_errors(self, *args, ax: Axes = None, **kwargs):
  """
  Plot biased, unbiased and total error in dB scaled.
 
@@ -4361,6 +4370,8 @@ def __init__(self, measured, ideals, switch_terms=None, isolation=None,
  **kwargs)
 
  def run(self):
+ from scipy.optimize import least_squares
+
  mList = [k for k in self.measured_unterminated]
  lm = mList[0]
  r1m = mList[1]

skrf/calibration/deembedding.py

@@ -59,11 +59,9 @@ class :class:`Deembedding`.
 import numpy as np
 from numpy import angle, concatenate, conj, exp, flip, real, zeros
 from numpy.fft import fft, fftshift, ifftshift, irfft
-from scipy.interpolate import interp1d
 
 from ..frequency import Frequency
 from ..network import Network, concat_ports, overlap_multi, subnetwork
-from ..util import subplots
 
 
 class Deembedding(ABC):
@@ -1102,6 +1100,8 @@ def dc_interp(self, s, f):
  enforces symmetric upon the first 10 points and interpolates the DC
  point.
  """
+ from scipy.interpolate import interp1d
+
  sp = s[0:9]
  fp = f[0:9]
 
@@ -1159,6 +1159,8 @@ def DC(self, s, f):
 
 
  def split2xthru(self, s2xthru):
+ from scipy.interpolate import interp1d
+
  f = s2xthru.frequency.f
  s = s2xthru.s
 
@@ -1222,6 +1224,9 @@ def split2xthru(self, s2xthru):
  z11x = z11[x]
 
  if self.verbose:
+ from ..plotting import plt
+ subplots = plt.subplots
+
  fig, (ax1, ax2) = subplots(2,1)
  fig.suptitle('Midpoint length and impedance determination')
  ax1.plot(t21, label = 't21')
@@ -1835,6 +1840,8 @@ def dc_interp(self, s, f):
  enforces symmetric upon the first 10 points and interpolates the DC
  point.
  """
+ from scipy.interpolate import interp1d
+
  sp = s[0:9]
  fp = f[0:9]
 
@@ -2104,6 +2111,9 @@ def makeErrorBox_v7(self, s_dut, s2x, gamma, z0, pullback):
  s11dut = s_dut.s[:, 0, 0]
  s22dut = s_dut.s[:, 1, 1]
  if self.verbose:
+ from ..plotting import plt
+ subplots = plt.subplots
+
  if i == 0:
  fig, axs = subplots(2, 2)
  axs[0, 0].plot(z1, color = 'k')
@@ -2150,6 +2160,9 @@ def makeErrorBox_v8(self, s_dut, s2x, gamma, z0, pullback):
  s_dut = sTL1.inv ** s_dut
  s11dut = s_dut.s[:, 0, 0]
  if self.verbose:
+ from ..plotting import plt
+ subplots = plt.subplots
+
  if i == 0:
  fig, axs = subplots(1, 2)
  axs[0].plot(z1, color = 'k')

skrf/circuit.py

@@ -98,9 +98,7 @@
 import numpy as np
 
 from .constants import INF, S_DEF_DEFAULT, NumberLike
-from .media import media
 from .network import Network, connect, innerconnect, s2s
-from .util import subplots
 
 if TYPE_CHECKING:
  from .frequency import Frequency
@@ -332,7 +330,8 @@ def Port(cls, frequency: Frequency, name: str, z0: float = 50) -> Network:
 
  In [18]: port1 = rf.Circuit.Port(freq, name='Port1')
  """
- _media = media.DefinedGammaZ0(frequency, z0=z0)
+ from .media import DefinedGammaZ0
+ _media = DefinedGammaZ0(frequency, z0=z0)
  port = _media.match(name=name)
  port._ext_attrs['_is_circuit_port'] = True
  return port
@@ -1365,6 +1364,8 @@ def plot_graph(self, **kwargs):
  'label_shift_y': 0
 
  """
+ import matplotlib.pyplot as plt
+ subplots = plt.subplots
 
  nx = self._get_nx()
  G = self.G

skrf/frequency.py

@@ -38,6 +38,12 @@
 
 from __future__ import annotations
 
+from typing import TYPE_CHECKING
+
+if TYPE_CHECKING:
+ from typing import TypeVar
+ Axes = TypeVar("Axes")
+
 import re
 import warnings
 from numbers import Number
@@ -51,7 +57,8 @@
 )
 
 from .constants import FREQ_UNITS, ZERO, NumberLike
-from .util import Axes, axes_kwarg, find_nearest_index, slice_domain
+from .plotting import axes_kwarg
+from .util import find_nearest_index, slice_domain
 
 
 class InvalidFrequencyWarning(UserWarning):

skrf/instances.py

@@ -58,7 +58,7 @@
 
 from .constants import mil
 from .frequency import Frequency
-from .media import Freespace, RectangularWaveguide
+from .media import DefinedGammaZ0, Freespace, RectangularWaveguide # noqa : F401
 
 
 class StaticInstances:

skrf/io/csv.py

@@ -57,8 +57,6 @@
 from ..frequency import Frequency
 from ..network import Network
 
-# delayed imports
-# from pandas import Series, Index, DataFrame
 
 def read_pna_csv(filename, *args, **kwargs):
  r"""

skrf/io/general.py

@@ -76,7 +76,6 @@
 from typing import Any
 
 import numpy as np
-from pandas import DataFrame, ExcelWriter, Series
 
 from ..frequency import Frequency
 from ..network import Network
@@ -668,6 +667,8 @@ def network_2_spreadsheet(ntwk: Network, file_name: str = None,
  --------
  networkset_2_spreadsheet : writes a spreadsheet for many networks
  """
+ import pandas as pd
+
  file_extns = {'csv':'csv','excel':'xls','html':'html'}
 
  form = form.lower()
@@ -691,23 +692,23 @@ def network_2_spreadsheet(ntwk: Network, file_name: str = None,
  if form =='db':
  for m,n in ntwk.port_tuples:
  d[f'S{ntwk._fmt_trace_name(m,n)} Log Mag(dB)'] = \
- Series(ntwk.s_db[:,m,n], index = index)
+ pd.Series(ntwk.s_db[:,m,n], index = index)
  d[f'S{ntwk._fmt_trace_name(m,n)} Phase(deg)'] = \
- Series(ntwk.s_deg[:,m,n], index = index)
+ pd.Series(ntwk.s_deg[:,m,n], index = index)
  elif form =='ma':
  for m,n in ntwk.port_tuples:
  d[f'S{ntwk._fmt_trace_name(m,n)} Mag(lin)'] = \
- Series(ntwk.s_mag[:,m,n], index = index)
+ pd.Series(ntwk.s_mag[:,m,n], index = index)
  d[f'S{ntwk._fmt_trace_name(m,n)} Phase(deg)'] = \
- Series(ntwk.s_deg[:,m,n], index = index)
+ pd.Series(ntwk.s_deg[:,m,n], index = index)
  elif form =='ri':
  for m,n in ntwk.port_tuples:
  d[f'S{ntwk._fmt_trace_name(m,n)} Real'] = \
- Series(ntwk.s_re[:,m,n], index = index)
+ pd.Series(ntwk.s_re[:,m,n], index = index)
  d[f'S{ntwk._fmt_trace_name(m,n)} Imag'] = \
- Series(ntwk.s_im[:,m,n], index = index)
+ pd.Series(ntwk.s_im[:,m,n], index = index)
 
- df = DataFrame(d)
+ df = pd.DataFrame(d)
  df.__getattribute__(f'to_{file_type}')(file_name,
  index_label=f'Freq({ntwk.frequency.unit})', **kwargs)
 
@@ -735,6 +736,8 @@ def network_2_dataframe(ntwk: Network, attrs: list[str] =None,
  -------
  df : pandas DataFrame Object
  """
+ import pandas as pd
+
  if attrs is None:
  attrs = ["s_db"]
  if ports is None:
@@ -748,7 +751,7 @@ def network_2_dataframe(ntwk: Network, attrs: list[str] =None,
  attr_array = getattr(ntwk, attr)
  for m, n in ports:
  d[f'{attr} {m+1}{port_sep}{n+1}'] = attr_array[:, m, n]
- return DataFrame(d, index=ntwk.frequency.f)
+ return pd.DataFrame(d, index=ntwk.frequency.f)
 
 def networkset_2_spreadsheet(ntwkset: NetworkSet, file_name: str = None, file_type: str = 'excel',
  *args, **kwargs):
@@ -789,6 +792,8 @@ def networkset_2_spreadsheet(ntwkset: NetworkSet, file_name: str = None, file_ty
  --------
  networkset_2_spreadsheet : writes a spreadsheet for many networks
  """
+ import pandas as pd
+
  if ntwkset.name is None and file_name is None:
  raise(ValueError('Either ntwkset must have name or give a file_name'))
  if file_name is None:
@@ -798,7 +803,7 @@ def networkset_2_spreadsheet(ntwkset: NetworkSet, file_name: str = None, file_ty
  # add file extension if missing
  if not file_name.endswith('.xlsx'):
  file_name += '.xlsx'
- with ExcelWriter(file_name) as writer:
+ with pd.ExcelWriter(file_name) as writer:
  [network_2_spreadsheet(k, writer, sheet_name=k.name, **kwargs) for k in ntwkset]
  else:
  [network_2_spreadsheet(k,*args, **kwargs) for k in ntwkset]

skrf/io/touchstone.py

@@ -26,6 +26,11 @@
 """
 from __future__ import annotations
 
+from typing import TYPE_CHECKING
+
+if TYPE_CHECKING:
+ from ..media import DefinedGammaZ0
+
 import os
 import re
 import typing
@@ -37,7 +42,6 @@
 import numpy as np
 
 from ..constants import FREQ_UNITS, S_DEF_HFSS_DEFAULT
-from ..media import DefinedGammaZ0
 from ..network import Network
 from ..util import get_fid
 
@@ -811,6 +815,8 @@ def hfss_touchstone_2_media(filename: str) -> list[DefinedGammaZ0]:
  --------
  hfss_touchstone_2_gamma_z0 : returns gamma, and z0
  """
+ from ..media import DefinedGammaZ0
+
  ntwk = Network(filename)
 
  freq = ntwk.frequency

skrf/mathFunctions.py

@@ -89,7 +89,6 @@
 
 import numpy as np
 from numpy import imag, pi, real, unwrap
-from scipy import signal
 
 from .constants import ALMOST_ZERO, EIG_COND, EIG_MIN, INF, LOG_OF_NEG, NumberLike
 
@@ -917,7 +916,7 @@ def psd2TimeDomain(f: np.ndarray, y: np.ndarray, windowType: str = 'hamming'):
  If spectrum is not baseband then, `timeSignal` is modulated by `exp(t*2*pi*f[0])`.
  So keep in mind units. Also, due to this, `f` must be increasing left to right.
  """
-
+ from scipy import signal
 
  # apply window function
  # make sure windowType exists in scipy.signal

skrf/media/circularWaveguide.py

@@ -15,7 +15,6 @@
 import numpy as np
 from numpy import sqrt, where
 from scipy.constants import epsilon_0, mu_0, pi
-from scipy.special import jn_zeros, jnp_zeros
 
 from ..constants import NumberLike
 from ..data import materials
@@ -162,6 +161,7 @@ def from_z0(cls, frequency: Frequency, z0: NumberLike,
  passed to :class:`~skrf.media.media.Media`'s constructor
  (:func:`~skrf.media.media.Media.__init__`
  """
+ from scipy.special import jnp_zeros
 
  mu = mu_0*mu_r
  ep = epsilon_0*ep_r
@@ -236,6 +236,8 @@ def kc(self) -> NumberLike:
  kc : number
  cut-off wavenumber
  """
+ from scipy.special import jn_zeros, jnp_zeros
+
  if self.mode_type =="te":
  u = jnp_zeros(self.m, self.n)[-1]
  elif self.mode_type =="tm":