Fix deprecation warning for Sympy 1.7

We have to try from newest to oldest import to avoid deprecation
warnings.

conftest.py

@@ -98,6 +98,10 @@ try:
 except ImportError:
     collect_ignore += [os.path.join(SCRIPT_FOLDER, "pystencils/datahandling/vtk.py")]
 
+# TODO: Remove if Ubuntu 18.04 is no longer supported
+if pytest_version < 50403:
+    collect_ignore += [os.path.join(SCRIPT_FOLDER, "pystencils_tests/test_jupyter_extensions.ipynb")]
+
 collect_ignore += [os.path.join(SCRIPT_FOLDER, 'setup.py')]
 
 for root, sub_dirs, files in os.walk('.'):

pystencils/assignment.py

 import numpy as np
 import sympy as sp
+from sympy.codegen.ast import Assignment
 from sympy.printing.latex import LatexPrinter
 
-try:
-    from sympy.codegen.ast import Assignment
-except ImportError:
-    Assignment = None
-
 __all__ = ['Assignment', 'assignment_from_stencil']
 
 
@@ -21,43 +17,22 @@ def assignment_str(assignment):
     return r"{lhs} ← {rhs}".format(lhs=assignment.lhs, rhs=assignment.rhs)
 
 
-if Assignment:
-
-    _old_new = sp.codegen.ast.Assignment.__new__
-
-    def _Assignment__new__(cls, lhs, rhs, *args, **kwargs):
-        if isinstance(lhs, (list, tuple, sp.Matrix)) and isinstance(rhs, (list, tuple, sp.Matrix)):
-            assert len(lhs) == len(rhs), f'{lhs} and {rhs} must have same length when performing vector assignment!'
-            return tuple(_old_new(cls, a, b, *args, **kwargs) for a, b in zip(lhs, rhs))
-        return _old_new(cls, lhs, rhs, *args, **kwargs)
-
-    Assignment.__str__ = assignment_str
-    Assignment.__new__ = _Assignment__new__
-    LatexPrinter._print_Assignment = print_assignment_latex
+_old_new = sp.codegen.ast.Assignment.__new__
 
-    sp.MutableDenseMatrix.__hash__ = lambda self: hash(tuple(self))
 
-else:
-    # back port for older sympy versions that don't have Assignment  yet
+def _Assignment__new__(cls, lhs, rhs, *args, **kwargs):
+    if isinstance(lhs, (list, tuple, sp.Matrix)) and isinstance(rhs, (list, tuple, sp.Matrix)):
+        assert len(lhs) == len(rhs), f'{lhs} and {rhs} must have same length when performing vector assignment!'
+        return tuple(_old_new(cls, a, b, *args, **kwargs) for a, b in zip(lhs, rhs))
+    return _old_new(cls, lhs, rhs, *args, **kwargs)
 
-    class Assignment(sp.Rel):  # pragma: no cover
 
-        rel_op = ':='
-        __slots__ = []
+Assignment.__str__ = assignment_str
+Assignment.__new__ = _Assignment__new__
+LatexPrinter._print_Assignment = print_assignment_latex
 
-        def __new__(cls, lhs, rhs=0, **assumptions):
-            from sympy.matrices.expressions.matexpr import (
-                MatrixElement, MatrixSymbol)
-            lhs = sp.sympify(lhs)
-            rhs = sp.sympify(rhs)
-            # Tuple of things that can be on the lhs of an assignment
-            assignable = (sp.Symbol, MatrixSymbol, MatrixElement, sp.Indexed)
-            if not isinstance(lhs, assignable):
-                raise TypeError(f"Cannot assign to lhs of type {type(lhs)}.")
-            return sp.Rel.__new__(cls, lhs, rhs, **assumptions)
+sp.MutableDenseMatrix.__hash__ = lambda self: hash(tuple(self))
 
-        __str__ = assignment_str
-        _print_Assignment = print_assignment_latex
 
 # Apparently, in SymPy 1.4 Assignment.__hash__ is not implemented. This has been fixed in current master
 try:

pystencils/backends/cbackend.py

@@ -18,12 +18,9 @@ from pystencils.integer_functions import (
     int_div, int_power_of_2, modulo_ceil)
 
 try:
-    from sympy.printing.ccode import C99CodePrinter as CCodePrinter
+    from sympy.printing.c import C99CodePrinter as CCodePrinter  # for sympy versions > 1.6
 except ImportError:
-    try:
-        from sympy.printing.ccode import CCodePrinter  # for sympy versions < 1.1
-    except ImportError:
-        from sympy.printing.c import C11CodePrinter as CCodePrinter  # for sympy versions > 1.6
+    from sympy.printing.ccode import C99CodePrinter as CCodePrinter
 
 __all__ = ['generate_c', 'CustomCodeNode', 'PrintNode', 'get_headers', 'CustomSympyPrinter']
 

pystencils/interpolation_astnodes.py

@@ -352,7 +352,7 @@ class InterpolatorAccess(TypedSymbol):
     __xnew_cached_ = staticmethod(cacheit(__new_stage2__))
 
     def __getnewargs__(self):
-        return tuple(self.symbol, *self.offsets)
+        return (self.symbol, *self.offsets)
 
 
 class DiffInterpolatorAccess(InterpolatorAccess):
@@ -397,7 +397,7 @@ class DiffInterpolatorAccess(InterpolatorAccess):
     __xnew_cached_ = staticmethod(cacheit(__new_stage2__))
 
     def __getnewargs__(self):
-        return tuple(self.symbol, self.diff_coordinate_idx, *self.offsets)
+        return (self.symbol, self.diff_coordinate_idx, *self.offsets)
 
 
 ##########################################################################################

pystencils_tests/test_astnodes.py

+import pytest
 import sympy as sp
-import pystencils as ps
 
+import pystencils as ps
 from pystencils import Assignment
-from pystencils.astnodes import Block, SkipIteration, LoopOverCoordinate, SympyAssignment
-from sympy.codegen.rewriting import optims_c99
+from pystencils.astnodes import Block, LoopOverCoordinate, SkipIteration, SympyAssignment
+
+sympy_numeric_version = [int(x, 10) for x in sp.__version__.split('.')]
+if len(sympy_numeric_version) < 3:
+    sympy_numeric_version.append(0)
+sympy_numeric_version.reverse()
+sympy_version = sum(x * (100 ** i) for i, x in enumerate(sympy_numeric_version))
 
 dst = ps.fields('dst(8): double[2D]')
 s = sp.symbols('s_:8')
@@ -11,6 +17,8 @@ x = sp.symbols('x')
 y = sp.symbols('y')
 
 
+@pytest.mark.skipif(sympy_version < 10501,
+                    reason="Old Sympy Versions behave differently which wont be supported in the near future")
 def test_kernel_function():
     assignments = [
         Assignment(dst[0, 0](0), s[0]),
@@ -36,6 +44,8 @@ def test_skip_iteration():
     assert skipped.undefined_symbols == set()
 
 
+@pytest.mark.skipif(sympy_version < 10501,
+                    reason="Old Sympy Versions behave differently which wont be supported in the near future")
 def test_block():
     assignments = [
         Assignment(dst[0, 0](0), s[0]),
@@ -83,7 +93,8 @@ def test_loop_over_coordinate():
 
 
 def test_sympy_assignment():
-
+    pytest.importorskip('sympy.codegen.rewriting')
+    from sympy.codegen.rewriting import optims_c99
     assignment = SympyAssignment(dst[0, 0](0), sp.log(x + 3) / sp.log(2) + sp.log(x ** 2 + 1))
     assignment.optimize(optims_c99)
 

pystencils_tests/test_basic_usage_llvm.ipynb

@@ -390,7 +390,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.6.5"
+   "version": "3.8.5"
   }
  },
  "nbformat": 4,

pystencils_tests/test_phasefield_dentritic_3D.ipynb

@@ -369,7 +369,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.6.9"
+   "version": "3.8.5"
   }
  },
  "nbformat": 4,