restructure setup extras, make mpl, scipy optional

.appveyor.yml

@@ -6,7 +6,7 @@ environment:
     - PYTHON: "C:\\Python35-x64"
     - PYTHON: "C:\\Python36-x64"
 install:
-  - "%PYTHON%\\python.exe -m pip install --upgrade .[test,mkl] coverage codecov"
+  - "%PYTHON%\\python.exe -m pip install --upgrade .[docs,matrix_scipy,matrix_mkl,export_mpl] coverage codecov"
 build: off
 test_script:
   - "%PYTHON%\\python.exe -m coverage run -m unittest -b"

.travis.yml

@@ -19,7 +19,7 @@ matrix:
 before_install:
   - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then wget -O python.pkg "$PYTHON_PKG_URL"; sudo installer -pkg python.pkg -target /; rm python.pkg; fi
 install:
-  - python3 -m pip install --upgrade .[test,mkl] coverage codecov $FORCE_PYTHON_PKGS
+  - python3 -m pip install --upgrade .[docs,matrix_scipy,matrix_mkl,export_mpl] coverage codecov $FORCE_PYTHON_PKGS
 script:
   - python3 -m coverage run -m unittest -b
 after_success:

examples/adaptivity.py

@@ -89,6 +89,7 @@ def main(etype: 'type of elements (square/triangle/mixed)' = 'square',
 
 class test(nutils.testing.TestCase):
 
+  @nutils.testing.requires('matplotlib')
   def test_square_quadratic(self):
     ndofs, error, rate, lhs = main(nrefine=2, etype='square', degree=2)
     self.assertEqual(ndofs, 149)
@@ -101,6 +102,7 @@ def test_square_quadratic(self):
       '+qV92kKevjK36ozDP/FSnh1iteWiqWuf+oMaKuyKaC1i52rKPokiF2WLA/20bya+ZCPbWKRPpv'
       'gFaedebw==')
 
+  @nutils.testing.requires('matplotlib')
   def test_triangle_quadratic(self):
     ndofs, error, rate, lhs = main(nrefine=2, etype='triangle', degree=2)
     self.assertEqual(ndofs, 98)
@@ -111,6 +113,7 @@ def test_triangle_quadratic(self):
       'MiXH+LXRR9NwoPkg82xN5IB2MZu2mGabSBnnAbGscYEJj3GVYQAQg/TVGfaA7RI0BsErRjeNeo'
       'wDgDQPmF9gkmciaJxtArGjzrAKCGWNpYAQAL0kOBE=')
 
+  @nutils.testing.requires('matplotlib')
   def test_mixed_linear(self):
     ndofs, error, rate, lhs = main(nrefine=2, etype='mixed', degree=1)
     self.assertEqual(ndofs, 34)

examples/burgers.py

@@ -60,16 +60,19 @@ def main(nelems: 'number of elements' = 20,
 
 class test(nutils.testing.TestCase):
 
+  @nutils.testing.requires('matplotlib')
   def test_1d_p1(self):
     lhs = main(ndims=1, nelems=10, timescale=.1, degree=1, endtime=.01)
     nutils.numeric.assert_allclose64(lhs, 'eNrbocann6u3yqjTyMLUwfSw2TWzKPNM8+9mH8wyTMNNZxptMir'
       'W49ffpwYAI6cOVA==')
 
+  @nutils.testing.requires('matplotlib')
   def test_1d_p2(self):
     lhs = main(ndims=1, nelems=10, timescale=.1, degree=2, endtime=.01)
     nutils.numeric.assert_allclose64(lhs, 'eNrr0c7SrtWfrD/d4JHRE6Ofxj6mnqaKZofNDpjZmQeYB5pHmL8'
       'we23mb5ZvWmjKY/LV6KPRFIMZ+o368dp92gCxZxZG')
 
+  @nutils.testing.requires('matplotlib')
   def test_2d_p1(self):
     lhs = main(ndims=2, nelems=4, timescale=.1, degree=1, endtime=.01)
     nutils.numeric.assert_allclose64(lhs, 'eNoNyKENhEAQRuGEQsCv2SEzyQZHDbRACdsDJNsBjqBxSBxBHIg'

examples/cahnhilliard.py

@@ -95,6 +95,7 @@ def _checkrand(self, lhs0):
       'xTJdjQ5yjEwWjX3MTk2n8kwNMbKTsoay1DMWDC8ycM1eTQyyb42NzdKNmLN5skSNs/LXDbnMuw'
       '19DNKNREtGTfui1ut')
 
+  @nutils.testing.requires('matplotlib')
   def test_square(self):
     lhs0, lhs = main(nelems=3, timestep=1, mtol=.1)
     self._checkrand(lhs0)
@@ -103,6 +104,7 @@ def test_square(self):
       'J01Pmp9MMY0y/WIYCOSZn7Q82XCi8UTXiSkn5pxYBISovJYTrSd6T0wD8xae6ATCCSemn5gLlu'
       'sFwiknZp9YcGIpEE4Ewhkn5p1YfGIFEKLyAN6wcSE=')
 
+  @nutils.testing.requires('matplotlib')
   def test_contactangle(self):
     lhs0, lhs = main(nelems=3, timestep=1, mtol=.1, contactangle=45)
     self._checkrand(lhs0)
@@ -112,6 +114,7 @@ def test_contactangle(self):
       'Mmz4CwzqTeZLbJNpOzJo+AcIrJVJO1JkdMbpi8BsLlJitM9gHNeGLy2eQLkLfSZL/JFZOnJl+B'
       'EAAJrlyi')
 
+  @nutils.testing.requires('matplotlib')
   def test_mixedcircle(self):
     lhs0, lhs = main(nelems=3, timestep=1, mtol=.1, circle=True, etype='mixed')
     self._checkrand(lhs0)

examples/cylinderflow.py

@@ -7,7 +7,7 @@
 # exponentially with radius such that the artificial exterior boundary is
 # placed at large (configurable) distance.
 
-import nutils, numpy, matplotlib.collections
+import nutils, numpy
 
 # The main function defines the parameter space for the script. Configurable
 # parameters are the mesh density (in number of elements along the cylinder
@@ -81,6 +81,7 @@ def main(nelems: 'number of elements' = 24,
     with nutils.export.mplfigure('flow.jpg', figsize=(12.8,7.2)) as fig:
       ax = fig.add_axes([0,0,1,1], yticks=[], xticks=[], frame_on=False, xlim=bbox[0], ylim=bbox[1])
       im = ax.tripcolor(x[:,0], x[:,1], bezier.tri, p, shading='gouraud', cmap='jet')
+      import matplotlib.collections
       ax.add_collection(matplotlib.collections.LineCollection(x[bezier.hull], colors='k', linewidths=.1, alpha=.5))
       ax.quiver(xgrd[:,0], xgrd[:,1], ugrd[:,0], ugrd[:,1], angles='xy', width=1e-3, headwidth=3e3, headlength=5e3, headaxislength=2e3, zorder=9, alpha=.5)
       ax.plot(0, 0, 'k', marker=(3,2,t*rotation*180/numpy.pi-90), markersize=20)
@@ -109,6 +110,7 @@ def main(nelems: 'number of elements' = 24,
 
 class test(nutils.testing.TestCase):
 
+  @nutils.testing.requires('matplotlib', 'scipy')
   def test_rot0(self):
     lhs0, lhs = main(nelems=6, reynolds=100, timestep=.1, endtime=.05, rotation=0)
     nutils.numeric.assert_allclose64(lhs0, 'eNqtjD8OwWAcQJ/JNSQ20Tbf135RkUjEZO8RJ'
@@ -121,6 +123,7 @@ def test_rot0(self):
       'Y+sMfJwavBhDNPPvbFV8cxOKk3ADtFOFI86zqjN9o8D8hcNFjCfsXVPd47Vj/qPdZBa0F5QUZD'
       '7UEJQYi527zjROVETUeVRfZIfrfvRKZKs7s6SVXLZ9k=')
 
+  @nutils.testing.requires('matplotlib', 'scipy')
   def test_rot1(self):
     lhs0, lhs = main(nelems=6, reynolds=100, timestep=.1, endtime=.05, rotation=1)
     nutils.numeric.assert_allclose64(lhs0, 'eNqtjD8OwWAcQJ/JNSQ20Tbf135RkUjEZO8RJ'

examples/drivencavity-compatible.py

@@ -9,7 +9,7 @@
 # uses the Raviart-Thomas discretization providing compatible velocity and
 # pressure spaces resulting in a pointwise divergence-free velocity field.
 
-import nutils, numpy, matplotlib.collections
+import nutils, numpy
 
 # The main function defines the parameter space for the script. Configurable
 # parameters are the mesh density (in number of elements along an edge),
@@ -71,6 +71,7 @@ def postprocess(domain, ns, every=.05, spacing=.01, **arguments):
   x, u, p, stream = bezier.eval(['x_i', 'sqrt(u_i u_i)', 'p', 'stream'] @ ns, **arguments)
   with nutils.export.mplfigure('flow.jpg') as fig: # plot velocity as field, pressure as contours, streamlines as dashed
     ax = fig.add_axes([.1,.1,.8,.8], yticks=[], aspect='equal')
+    import matplotlib.collections
     ax.add_collection(matplotlib.collections.LineCollection(x[bezier.hull], colors='w', linewidths=.5, alpha=.2))
     ax.tricontour(x[:,0], x[:,1], bezier.tri, stream, 16, colors='k', linestyles='dotted', linewidths=.5, zorder=9)
     caxu = fig.add_axes([.1,.1,.03,.8], title='velocity')
@@ -97,13 +98,15 @@ def postprocess(domain, ns, every=.05, spacing=.01, **arguments):
 
 class test(nutils.testing.TestCase):
 
+  @nutils.testing.requires('matplotlib')
   def test_p1(self):
     lhs0, lhs1 = main(nelems=3, reynolds=100, degree=2)
     nutils.numeric.assert_allclose64(lhs0, 'eNpTvPBI3/o0t1mzds/pltM65opQ/n196QvcZh4XO03MTHbolZ'
       '8+dVrxwlP9rycVL03Xjbm45tQfrZc37M/LGLBcFVc/aPDk/H3dzEtL9EJMGRgAJt4mPA==')
     nutils.numeric.assert_allclose64(lhs1, 'eNoBUgCt/6nOuTGJy4M1SCzJy4zLCjcsLk3PCst/Nlcx9M2DNe'
       'DPgDR+NB7UG8wVzSwuPc6ByezUQiudMKTL/y4AL73NLS6jLUov8s4zzXoscdMJMSo2AABO+yTF')
 
+  @nutils.testing.requires('matplotlib')
   def test_p2(self):
     lhs0, lhs1 = main(nelems=3, reynolds=100, degree=3)
     nutils.numeric.assert_allclose64(lhs0, 'eNp7ZmB71sY46VSq2dLzludvnMo20jFHsJ7BZaXObzbedDrVbJ'

examples/drivencavity.py

@@ -5,7 +5,7 @@
 # bottom and right boundaries and a top boundary that is moving at unit
 # velocity in positive x-direction.
 
-import nutils, numpy, matplotlib.collections
+import nutils, numpy
 
 # The main function defines the parameter space for the script. Configurable
 # parameters are the mesh density (in number of elements along an edge),
@@ -67,6 +67,7 @@ def postprocess(domain, ns, every=.05, spacing=.01, **arguments):
   x, u, p, stream = bezier.eval(['x_i', 'sqrt(u_k u_k)', 'p', 'stream'] @ ns, **arguments)
   with nutils.export.mplfigure('flow.jpg') as fig: # plot velocity as field, pressure as contours, streamlines as dashed
     ax = fig.add_axes([.1,.1,.8,.8], yticks=[], aspect='equal')
+    import matplotlib.collections
     ax.add_collection(matplotlib.collections.LineCollection(x[bezier.hull], colors='w', linewidths=.5, alpha=.2))
     ax.tricontour(x[:,0], x[:,1], bezier.tri, stream, 16, colors='k', linestyles='dotted', linewidths=.5, zorder=9)
     caxu = fig.add_axes([.1,.1,.03,.8], title='velocity')
@@ -92,6 +93,7 @@ def postprocess(domain, ns, every=.05, spacing=.01, **arguments):
 
 class test(nutils.testing.TestCase):
 
+  @nutils.testing.requires('matplotlib')
   def test_square(self):
     lhs0, lhs1 = main(nelems=3, etype='square', reynolds=100, degree=3)
     nutils.numeric.assert_allclose64(lhs0, 'eNp1zj1IQlEUB/BrCJKEQxLRFNFQxvN1vTcpo'
@@ -110,6 +112,7 @@ def test_square(self):
       'chLfnV63yLT/Pd2CKLXqfadsL9DmGmLeruPPl42diN/44jyV8wBuMogvteIe827MYxwTWkMOiK'
       '1k8QxrTbl9xZQpPMIzn2EDR3cgjg5dYxzYKKIHjDzbx252sY9mdHuKHaRj/AYh1yFc=')
 
+  @nutils.testing.requires('matplotlib')
   def test_mixed(self):
     lhs0, lhs1 = main(nelems=3, etype='mixed', reynolds=100, degree=2)
     nutils.numeric.assert_allclose64(lhs0, 'eNpjYICAiRePnWdg0D736SyIF3P2nK6VYSWQH'

examples/elasticity.py

@@ -60,19 +60,22 @@ def main(nelems: 'number of elements along edge' = 10,
 
 class test(nutils.testing.TestCase):
 
+  @nutils.testing.requires('matplotlib')
   def test_default(self):
     cons, lhs = main(nelems=4)
     nutils.numeric.assert_allclose64(cons, 'eNpjYICDBnzwhykMMhCpAwEBQ08XYg==')
     nutils.numeric.assert_allclose64(lhs, 'eNpjYICBFGMxYyEgTjFebDLBpB2IF5tkmKaYJg'
       'JxhukPOIRrYBA1CjJgYFh3/vXZMiMVQwaGO+e6zvYY2QBZR86VnO2FsorPAgAXLB7S')
 
+  @nutils.testing.requires('matplotlib')
   def test_mixed(self):
     cons, lhs = main(nelems=4, etype='mixed')
     nutils.numeric.assert_allclose64(cons, 'eNpjYACCBiBkQMJY4A9TGGQgUgcCAgBVTxdi')
     nutils.numeric.assert_allclose64(lhs, 'eNpjYGBgSDKWNwZSQKwExAnGfSbLTdpNek2WmW'
       'SYppgmAHGG6Q84BKpk4DASN2Bg2K/JwHDrPAPDj7MqhnlGRddenpt+ts/I0nChyrlzJWcdDbuN'
       'YjUOnSs/CwB0uyJb')
 
+  @nutils.testing.requires('matplotlib')
   def test_quadratic(self):
     cons, lhs = main(nelems=4, degree=2)
     nutils.numeric.assert_allclose64(cons, 'eNpjYMAADQMJf5iiQ4ZB5kJMCAAkxE4W')
@@ -82,6 +85,7 @@ def test_quadratic(self):
       'Hw4sTzU859PZtldNGQ3XCCPgNDwYWf5/TPTTtbYvTKUNpwP1DE8cLTc2Lnes62Gf01NDW8BxRR'
       'unD6HPO5KqjIA6CIAlSkw+ifobnhI6CI3IWT55jOVQBF/hqaGT4EishfOAVUU3EWAA5lcd0=')
 
+  @nutils.testing.requires('matplotlib')
   def test_poisson(self):
     cons, lhs = main(nelems=4, poisson=.4)
     nutils.numeric.assert_allclose64(cons, 'eNpjYICDBnzwhykMMhCpAwEBQ08XYg==')

examples/finitestrain.py

@@ -76,6 +76,7 @@ def main(nelems: 'number of elements along edge' = 10,
 
 class test(nutils.testing.TestCase):
 
+  @nutils.testing.requires('matplotlib')
   def test_default(self):
     lhs0, lhs1 = main(nelems=4, angle=10)
     nutils.numeric.assert_allclose64(lhs0, 'eNpjYICB8ku8+icMthvOM+K42G1ga6Rv/Mh42'
@@ -85,6 +86,7 @@ def test_default(self):
       'wxdjAVM2k1uX1A22mjcbaJsCtfAoHz53sXiC27nGc6pnD94Tutc5dlLZyLOSpw9fab4DOsZyTM'
       'fTp88vex0y2kA6e4nVQ==')
 
+  @nutils.testing.requires('matplotlib')
   def test_mixed(self):
     lhs0, lhs1 = main(nelems=4, angle=10, etype='mixed')
     nutils.numeric.assert_allclose64(lhs0, 'eNoBZACb/wAAAADV0WwvAAChMAAAtjEAAKgyX'
@@ -94,6 +96,7 @@ def test_mixed(self):
       'zGKLIEySDPKM6fS9TFCMwM0mzQjMtvQsTOLNCM1AAAAAD/TYNEAAN7QAAA3zwAACc7SzgnPEc6'
       'TzdjMZ80TzdHMa8wXzPDLGczJy6bLhMthnih2')
 
+  @nutils.testing.requires('matplotlib')
   def test_spline(self):
     lhs0, lhs1 = main(nelems=4, angle=10, degree=2, btype='spline')
     nutils.numeric.assert_allclose64(lhs0, 'eNpjYECAa1e+aE3Qu6Nfa9BlmHoxU/eHgbIRs'

examples/laplace.py

@@ -120,6 +120,7 @@ def main(nelems: 'number of elements along edge' = 10,
 
 class test(nutils.testing.TestCase):
 
+  @nutils.testing.requires('matplotlib')
   def test_default(self):
     cons, lhs, err = main(nelems=4, etype='square', btype='std', degree=1)
     nutils.numeric.assert_allclose64(cons, 'eNrbKPv1QZ3ip9sL1BgaILDYFMbaZwZj5ZnDW'
@@ -128,6 +129,7 @@ def test_default(self):
       'XyNR82ZTa+NpI2oTbPNhU3bjf7Ngo3ODd+N9c3SNEU1g==')
     numpy.testing.assert_almost_equal(err, 1.63e-3, decimal=5)
 
+  @nutils.testing.requires('matplotlib')
   def test_spline(self):
     cons, lhs, err = main(nelems=4, etype='square', btype='spline', degree=2)
     nutils.numeric.assert_allclose64(cons, 'eNqrkmN+sEfhzF0xleRbDA0wKGeCYFuaIdjK5'
@@ -136,6 +138,7 @@ def test_spline(self):
       'gmmNaZ7jBlN7M08wLCDLNFZh/NlM0vmV0y+2CmZV5pvtr8j9kfMynzEPPF5lfNAcuhGvs=')
     numpy.testing.assert_almost_equal(err, 8.04e-5, decimal=7)
 
+  @nutils.testing.requires('matplotlib')
   def test_mixed(self):
     cons, lhs, err = main(nelems=4, etype='mixed', btype='std', degree=2)
     nutils.numeric.assert_allclose64(cons, 'eNorfLZF2ucJQwMC3pR7+QDG9lCquAtj71Rlu'

examples/platewithhole-nurbs.py

@@ -97,6 +97,7 @@ def main(nrefine = 2,
 
 class test(nutils.testing.TestCase):
 
+  @nutils.testing.requires('matplotlib')
   def test0(self):
     err, cons, lhs = main(nrefine=0)
     nutils.numeric.assert_allclose64(err, 'eNoT1r6hDwACsAFG')
@@ -105,6 +106,7 @@ def test0(self):
     nutils.numeric.assert_allclose64(lhs, 'eNoBMADP/1jZ0DGVM5YzzSjfL2kzqDMz1ygzHj'
       'PTM5LOr85F0GgpJc6GzrIuc9Qdzm7Pvc+NKyFrF1c=')
 
+  @nutils.testing.requires('matplotlib')
   def test2(self):
     err, cons, lhs = main(nrefine=2)
     nutils.numeric.assert_allclose64(err, 'eNqzUn2kDQADSgFt')

examples/platewithhole.py

@@ -77,6 +77,7 @@ def main(nelems: 'number of elementsa long edge' = 9,
 
 class test(nutils.testing.TestCase):
 
+  @nutils.testing.requires('matplotlib')
   def test_spline(self):
     err, cons, lhs = main(nelems=4, etype='square', degree=2, btype='spline')
     nutils.numeric.assert_allclose64(err, 'eNpbpd6jCwAEZgGL')
@@ -88,6 +89,7 @@ def test_spline(self):
       'zi/OGclHzJfOSs45zjDOOSK7z5fPC8+cznzOBd/D3d3RFdAuz+vO+yGg1bnSvdCoz03Pzdz01a'
       'zS3dDLz2zPaQdIRw==')
 
+  @nutils.testing.requires('matplotlib')
   def test_mixed(self):
     err, cons, lhs = main(nelems=4, etype='mixed', degree=2, btype='std')
     nutils.numeric.assert_allclose64(err, 'eNpjU9+jCwACNgEX')

readthedocs.yml

@@ -5,4 +5,3 @@ python:
   pip_install: true
   extra_requirements:
     - docs
-    - readthedocs

setup.py

@@ -23,8 +23,6 @@
 with open(os.path.join('nutils', '__init__.py')) as f:
   version = next(filter(None, map(re.compile("^version = '([a-zA-Z0-9.]+)'$").match, f))).group(1)
 
-tests_require = ['Sphinx>=1.6','pillow>2.6']
-
 setup(
   name = 'nutils',
   version = version,
@@ -37,13 +35,12 @@
   long_description = long_description,
   license = 'MIT',
   python_requires = '>=3.5',
-  install_requires = ['numpy>=1.12', 'matplotlib>=1.3', 'scipy>=0.13', 'treelog', 'stickybar'],
-  tests_require = tests_require,
+  install_requires = ['numpy>=1.12', 'treelog', 'stickybar'],
   extras_require = dict(
-    test=tests_require,
-    docs=['Sphinx>=1.6'],
-    mkl=['mkl'],
-    readthedocs=['pillow>2.6'],
+    docs=['Sphinx>=1.6','scipy>=0.13','matplotlib>=1.3','pillow>2.6'],
+    matrix_scipy=['scipy>=0.13'],
+    matrix_mkl=['mkl','tbb;platform_system!="Windows"'],
+    export_mpl=['matplotlib>=1.3','pillow>2.6'],
   ),
   command_options = dict(
     test=dict(test_loader=('setup.py', 'unittest:TestLoader')),

tests/test_export.py

@@ -9,6 +9,7 @@ def setUpContext(self, stack):
     self.outdir = pathlib.Path(stack.enter_context(tempfile.TemporaryDirectory()))
     stack.enter_context(treelog.set(treelog.DataLog(str(self.outdir))))
 
+  @nutils.testing.requires('matplotlib', 'PIL')
   def test_autodetect_imagetype(self):
     for (imagetype, test) in (('jpg', lambda data: self.assertEqual(data[:3], b'\xFF\xD8\xFF')),
                               ('png', lambda data: self.assertEqual(data[:8], b'\x89\x50\x4E\x47\x0D\x0A\x1A\x0A')),

tests/test_quadrature.py

@@ -1,6 +1,6 @@
 from nutils import *
 from nutils.testing import *
-import scipy.special, re
+import math, re
 
 
 @parametrize
@@ -17,7 +17,8 @@ def setUp(self):
       self.integrals = numpy.reciprocal((self.monomials+1.).prod(-1))
     else:
       self.ref = element.getsimplex(self.ndims)
-      self.integrals = scipy.special.gamma(self.monomials+1.).prod(-1) / scipy.special.gamma(self.ndims+1+self.monomials.sum(-1))
+      gamma = numpy.vectorize(math.gamma)
+      self.integrals = gamma(self.monomials+1.).prod(-1) / gamma(self.ndims+1+self.monomials.sum(-1))
 
   def test_degree(self):
     for degree in range(1, self.maxdegree+1):

tests/test_util.py

@@ -14,11 +14,13 @@ def setUp(self):
     self.x = numpy.array([[0,0],[1,0],[0,1],[1,0],[0,1],[1,1]], dtype=float)
     self.tri = numpy.array([[0,1,2],[3,4,5]])
 
+  @requires('scipy')
   def test_merge(self):
     tri_merged = util.tri_merge(self.tri, self.x, mergetol=self.mergetol).tolist()
     tri_expected = self.tri.tolist() if self.mergetol < 0 else [[0,1,2],[1,2,5]] if self.mergetol < 1 else [[0,0,0],[0,0,0]]
     self.assertEqual(tri_merged, tri_expected)
 
+  @requires('matplotlib', 'scipy')
   def test_interpolate(self):
     interpolate = util.tri_interpolator(self.tri, self.x, mergetol=self.mergetol)
     x = [.1, .9],
@@ -36,6 +38,7 @@ def test_interpolate(self):
         self.assertTrue(numpy.isnan(vx).all())
 
   @parametrize.enable_if(lambda mergetol: 0 <= mergetol < 1)
+  @requires('matplotlib', 'scipy')
   def test_outofbounds(self):
     interpolate = util.tri_interpolator(self.tri, self.x, mergetol=self.mergetol)
     x = [.5, .5], [1.5, .5]