problem in lanczos sampler

[shahdloo]

I try to produce a flatmap with Lanczos sampling:

cortex.quickflat.make_png('test.png', cortex.Volume(data=np.random.rand(32,100,100), subject=subject, xfmname=xfmname), sampler='lanczos')

Pycortex creates a pool of 48 processes and it never ends processing. I kill it by keyboard interrupt. The following is the traceback I get:

---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
~/Projs/bilPype/venv/lib/python3.5/site-packages/cortex/mp.py in map(func, iterable, procs)
     41     try:
---> 42         progress = pb.ProgressBar(widgets=[pb.Percentage(), pb.Bar()], maxval=iterlen)
     43         progress.start()

NameError: name 'pb' is not defined

During handling of the above exception, another exception occurred:

KeyboardInterrupt                         Traceback (most recent call last)
<ipython-input-84-6ed4544576a7> in <module>()
      4                                                     mask='thick',
      5                                                    vmax = 200),
----> 6                          sampler='lanczos')

~/Projs/bilPype/venv/lib/python3.5/site-packages/cortex/quickflat/view.py in make_png(fname, braindata, recache, pixelwise, sampler, height, bgcolor, dpi, **kwargs)
    257                       sampler=sampler,
    258                       height=height,
--> 259                       **kwargs)
    260 
    261     imsize = fig.get_axes()[0].get_images()[0].get_size()

~/Projs/bilPype/venv/lib/python3.5/site-packages/cortex/quickflat/view.py in make_figure(braindata, recache, pixelwise, thick, sampler, height, dpi, depth, with_rois, with_sulci, with_labels, with_colorbar, with_borders, with_dropout, with_curvature, extra_disp, with_connected_vertices, linewidth, linecolor, roifill, shadow, labelsize, labelcolor, cutout, curvature_brightness, curvature_contrast, curvature_threshold, fig, extra_hatch, colorbar_ticks, colorbar_location, roi_list, **kwargs)
    103     # Add data
    104     data_im, extents = composite.add_data(fig, dataview, pixelwise=pixelwise, thick=thick, sampler=sampler,
--> 105                        height=height, depth=depth, recache=recache)
    106 
    107     layers = dict(data=data_im)

~/Projs/bilPype/venv/lib/python3.5/site-packages/cortex/quickflat/composite.py in add_data(fig, braindata, height, thick, depth, pixelwise, sampler, recache)
    162     # Generate image (2D array, maybe 3D array)
    163     im, extents = make_flatmap_image(dataview, recache=recache, pixelwise=pixelwise, sampler=sampler,
--> 164                        height=height, thick=thick, depth=depth)
    165     # Check whether dataview has a cmap instance
    166     cmapdict = _has_cmap(dataview)

~/Projs/bilPype/venv/lib/python3.5/site-packages/cortex/quickflat/utils.py in make_flatmap_image(braindata, height, recache, **kwargs)
     57                                height=height,
     58                                recache=recache,
---> 59                                **kwargs)
     60         if isinstance(braindata, dataset.Volume2D):
     61             data = braindata.raw.volume

~/Projs/bilPype/venv/lib/python3.5/site-packages/cortex/quickflat/utils.py in get_flatcache(subject, xfmname, pixelwise, thick, sampler, recache, height, depth)
    141         print("Generating a flatmap cache")
    142         if pixelwise and xfmname is not None:
--> 143             pixmap = _make_pixel_cache(subject, xfmname, height=height, sampler=sampler, thick=thick, depth=depth)
    144         else:
    145             pixmap = _make_vertex_cache(subject, height=height)

~/Projs/bilPype/venv/lib/python3.5/site-packages/cortex/quickflat/utils.py in _make_pixel_cache(subject, xfmname, height, thick, depth, sampler)
    395 
    396         for t in np.linspace(0, 1, thick+2)[1:-1]:
--> 397             i, j, data = sampclass(piacoords[valid]*t + wmcoords[valid]*(1-t), xfm.shape)
    398             mapper = mapper + sparse.csr_matrix((data / float(thick), (vidx[i], j)),
    399                                                 shape=mapper.shape)

~/Projs/bilPype/venv/lib/python3.5/site-packages/cortex/mapper/samplers.py in lanczos(coords, shape, window, **kwargs)
     97         return out
     98 
---> 99     return distance_func(lanczos, coords, shape, **kwargs)

~/Projs/bilPype/venv/lib/python3.5/site-packages/cortex/mapper/samplers.py in distance_func(func, coords, shape, renorm, mp)
     76     if mp:
     77         from .. import mp
---> 78         ijdata = mp.map(func, range(len(coords)))
     79     else:
     80         #ijdata = map(func, range(len(coords)))

~/Projs/bilPype/venv/lib/python3.5/site-packages/cortex/mp.py in map(func, iterable, procs)
     49     except NameError:
     50         for _ in range(iterlen):
---> 51             idx, result = output.get()
     52             data[idx] = result
     53 

/usr/local/lib/python3.5/multiprocessing/queues.py in get(self, block, timeout)
     92         if block and timeout is None:
     93             with self._rlock:
---> 94                 res = self._recv_bytes()
     95             self._sem.release()
     96         else:

/usr/local/lib/python3.5/multiprocessing/connection.py in recv_bytes(self, maxlength)
    214         if maxlength is not None and maxlength < 0:
    215             raise ValueError("negative maxlength")
--> 216         buf = self._recv_bytes(maxlength)
    217         if buf is None:
    218             self._bad_message_length()

/usr/local/lib/python3.5/multiprocessing/connection.py in _recv_bytes(self, maxsize)
    405 
    406     def _recv_bytes(self, maxsize=None):
--> 407         buf = self._recv(4)
    408         size, = struct.unpack("!i", buf.getvalue())
    409         if maxsize is not None and size > maxsize:

/usr/local/lib/python3.5/multiprocessing/connection.py in _recv(self, size, read)
    377         remaining = size
    378         while remaining > 0:
--> 379             chunk = read(handle, remaining)
    380             n = len(chunk)
    381             if n == 0:

I suspect it enters an infinite recursion but I cannot figure out how and where.