Merge pull request #459 from rht/import

quad: Import sympy only when necessary

quantecon/arma.py

@@ -6,7 +6,6 @@
 """
 import numpy as np
 from numpy import conj, pi
-from scipy.signal import dimpulse, freqz, dlsim
 from .util import check_random_state
 
 
@@ -61,7 +60,6 @@ class ARMA:
  processing we desire. Corresponds with the theta values
 
  """
-
  def __init__(self, phi, theta=0, sigma=1):
  self._phi, self._theta = phi, theta
  self.sigma = sigma
@@ -165,6 +163,7 @@ def impulse_response(self, impulse_length=30):
  We take psi[0] as unity.
 
  """
+ from scipy.signal import dimpulse
  sys = self.ma_poly, self.ar_poly, 1
  times, psi = dimpulse(sys, n=impulse_length)
  psi = psi[0].flatten() # Simplify return value into flat array
@@ -205,6 +204,7 @@ def spectral_density(self, two_pi=True, res=1200):
  The frequency response
 
  """
+ from scipy.signal import freqz
  w, h = freqz(self.ma_poly, self.ar_poly, worN=res, whole=two_pi)
  spect = h * conj(h) * self.sigma**2
 
@@ -249,6 +249,7 @@ def simulation(self, ts_length=90, random_state=None):
  A simulation of the model that corresponds to this class
 
  """
+ from scipy.signal import dlsim
  random_state = check_random_state(random_state)
 
  sys = self.ma_poly, self.ar_poly, 1

quantecon/quad.py

@@ -14,7 +14,6 @@
 import numpy as np
 import scipy.linalg as la
 from numba import jit, vectorize
-import sympy as sym
 from .ce_util import ckron, gridmake
 from .util import check_random_state
 
@@ -141,6 +140,7 @@ def qnwequi(n, a, b, kind="N", equidist_pp=None, random_state=None):
  random_state = check_random_state(random_state)
 
  if equidist_pp is None:
+ import sympy as sym
  equidist_pp = np.sqrt(np.array(list(sym.primerange(0, 7920))))
 
  n, a, b = list(map(np.atleast_1d, list(map(np.asarray, [n, a, b]))))

quantecon/random/utilities.py

@@ -89,10 +89,12 @@ def _probvec(r, out):
  out[n] = 1 - r[n-1]
 
 _probvec_parallel = guvectorize(
- ['(f8[:], f8[:])'], '(n), (k)', nopython=True, target='parallel'
+ ['(f8[:], f8[:])'], '(n), (k)', nopython=True, target='parallel',
+ cache=True
  )(_probvec)
 _probvec_cpu = guvectorize(
- ['(f8[:], f8[:])'], '(n), (k)', nopython=True, target='cpu'
+ ['(f8[:], f8[:])'], '(n), (k)', nopython=True, target='cpu',
+ cache=True
  )(_probvec)
 
 

quantecon/util/notebooks.py

@@ -20,7 +20,6 @@
 """
 
 import os
-import requests
 import warnings
 
 #-Remote Structure-#
@@ -72,6 +71,7 @@ def fetch_nb_dependencies(files, repo=REPO, raw=RAW, branch=BRANCH, folder=FOLDE
  by setting ``overwrite=True``.
 
  """
+ import requests
 
  #-Generate Common Data Structure-#
  if type(files) == list: