load external dependencies only when it is necessary

nifty2go/operators/fft_operator/transformations/gllmtransformation.py

@@ -19,7 +19,6 @@
 import numpy as np
 from .slicing_transformation import SlicingTransformation
 from . import lm_transformation_helper
-import pyHealpix
 
 
 class GLLMTransformation(SlicingTransformation):
@@ -31,10 +30,12 @@ class GLLMTransformation(SlicingTransformation):
         return False
 
     def _transformation_of_slice(self, inp):
+        from pyHealpix import sharpjob_d
+
         lmax = self.codomain.lmax
         mmax = self.codomain.mmax
 
-        sjob = pyHealpix.sharpjob_d()
+        sjob = sharpjob_d()
         sjob.set_Gauss_geometry(self.domain.nlat, self.domain.nlon)
         sjob.set_triangular_alm_info(lmax, mmax)
         if issubclass(inp.dtype.type, np.complexfloating):

nifty2go/operators/fft_operator/transformations/hplmtransformation.py

@@ -19,7 +19,6 @@
 import numpy as np
 from .slicing_transformation import SlicingTransformation
 from . import lm_transformation_helper
-import pyHealpix
 
 
 class HPLMTransformation(SlicingTransformation):
@@ -31,16 +30,18 @@ class HPLMTransformation(SlicingTransformation):
         return False
 
     def _transformation_of_slice(self, inp):
+        from pyHealpix import map2alm
+
         lmax = self.codomain.lmax
         mmax = lmax
 
         if issubclass(inp.dtype.type, np.complexfloating):
-            rr = pyHealpix.map2alm(inp.real, lmax, mmax)
+            rr = map2alm(inp.real, lmax, mmax)
             rr = lm_transformation_helper.buildIdx(rr, lmax=lmax)
-            ri = pyHealpix.map2alm(inp.imag, lmax, mmax)
+            ri = map2alm(inp.imag, lmax, mmax)
             ri = lm_transformation_helper.buildIdx(ri, lmax=lmax)
             return rr + 1j*ri
 
         else:
-            rr = pyHealpix.map2alm(inp, lmax, mmax)
+            rr = map2alm(inp, lmax, mmax)
             return lm_transformation_helper.buildIdx(rr, lmax=lmax)

nifty2go/operators/fft_operator/transformations/lmgltransformation.py

@@ -19,7 +19,6 @@
 import numpy as np
 from .slicing_transformation import SlicingTransformation
 from . import lm_transformation_helper
-import pyHealpix
 
 
 class LMGLTransformation(SlicingTransformation):
@@ -31,10 +30,12 @@ class LMGLTransformation(SlicingTransformation):
         return False
 
     def _transformation_of_slice(self, inp):
+        from pyHealpix import sharpjob_d
+
         lmax = self.domain.lmax
         mmax = self.domain.mmax
 
-        sjob = pyHealpix.sharpjob_d()
+        sjob = sharpjob_d()
         sjob.set_Gauss_geometry(self.codomain.nlat, self.codomain.nlon)
         sjob.set_triangular_alm_info(lmax, mmax)
         if issubclass(inp.dtype.type, np.complexfloating):

nifty2go/operators/fft_operator/transformations/lmhptransformation.py

@@ -19,7 +19,6 @@
 import numpy as np
 from .slicing_transformation import SlicingTransformation
 from . import lm_transformation_helper
-import pyHealpix
 
 
 class LMHPTransformation(SlicingTransformation):
@@ -32,6 +31,8 @@ class LMHPTransformation(SlicingTransformation):
         return False
 
     def _transformation_of_slice(self, inp):
+        from pyHealpix import alm2map
+
         nside = self.codomain.nside
         lmax = self.domain.lmax
         mmax = lmax
@@ -39,10 +40,10 @@ class LMHPTransformation(SlicingTransformation):
         if issubclass(inp.dtype.type, np.complexfloating):
             rr = lm_transformation_helper.buildLm(inp.real, lmax=lmax)
             ri = lm_transformation_helper.buildLm(inp.imag, lmax=lmax)
-            rr = pyHealpix.alm2map(rr, lmax, mmax, nside)
-            ri = pyHealpix.alm2map(ri, lmax, mmax, nside)
+            rr = alm2map(rr, lmax, mmax, nside)
+            ri = alm2map(ri, lmax, mmax, nside)
             return rr + 1j*ri
 
         else:
             rr = lm_transformation_helper.buildLm(inp, lmax=lmax)
-            return pyHealpix.alm2map(rr, lmax, mmax, nside)
+            return alm2map(rr, lmax, mmax, nside)

nifty2go/operators/fft_operator/transformations/rg_transforms.py

@@ -17,7 +17,6 @@
 # and financially supported by the Studienstiftung des deutschen Volkes.
 
 from builtins import object, range
-import pyfftw
 
 
 class SerialFFT(object):
@@ -25,6 +24,8 @@ class SerialFFT(object):
         The pyfftw pendant of a fft object.
     """
     def __init__(self, domain, codomain):
+        import pyfftw
+
         self.domain = domain
         self.codomain = codomain
 
@@ -48,6 +49,7 @@ class SerialFFT(object):
             result : numpy.ndarray
                 Fourier-transformed pendant of the input field.
         """
+        from pyfftw.interfaces.numpy_fft import fftn, ifftn
 
         # Check if the axes provided are valid given the shape
         if axes is not None and \
@@ -55,6 +57,6 @@ class SerialFFT(object):
             raise ValueError("Provided axes does not match array shape")
 
         if self.codomain.harmonic:
-            return pyfftw.interfaces.numpy_fft.fftn(val, axes=axes)
+            return fftn(val, axes=axes)
         else:
-            return pyfftw.interfaces.numpy_fft.ifftn(val, axes=axes)
+            return ifftn(val, axes=axes)

nifty2go/spaces/gl_space/gl_space.py

@@ -17,12 +17,9 @@
 # and financially supported by the Studienstiftung des deutschen Volkes.
 
 from __future__ import division
-
 import itertools
 import numpy as np
-
 from ..space import Space
-import pyHealpix
 
 
 class GLSpace(Space):
@@ -65,8 +62,6 @@ class GLSpace(Space):
         ------
         ValueError
             If input `nlat` or `nlon` is invalid.
-        ImportError
-            If the pyHealpix module is not available
 
         See Also
         --------
@@ -87,10 +82,6 @@ class GLSpace(Space):
     # ---Overwritten properties and methods---
 
     def __init__(self, nlat, nlon=None):
-        if pyHealpix is None:
-            raise ImportError(
-                "The module pyHealpix is needed but not available.")
-
         super(GLSpace, self).__init__()
 
         self._nlat = self._parse_nlat(nlat)
@@ -122,9 +113,10 @@ class GLSpace(Space):
                               nlon=self.nlon)
 
     def weight(self, x, power=1, axes=None, inplace=False):
+        from pyHealpix import GL_weights
         nlon = self.nlon
         nlat = self.nlat
-        vol = pyHealpix.GL_weights(nlat, nlon) ** np.float(power)
+        vol = GL_weights(nlat, nlon) ** np.float(power)
         weight = np.array(list(itertools.chain.from_iterable(
                           itertools.repeat(x, nlon) for x in vol)))