Fixed Wrong fString in Cuda Backend

pystencils/backends/cuda_backend.py

@@ -98,7 +98,7 @@ class CudaSympyPrinter(CustomSympyPrinter):
         if isinstance(expr, fast_division):
             return "__fdividef(%s, %s)" % tuple(self._print(a) for a in expr.args)
         elif isinstance(expr, fast_sqrt):
-            return f"__fsqrt_rn({tuple(self._print(a) for a in expr.args)})"
+            return "__fsqrt_rn(%s)" % tuple(self._print(a) for a in expr.args)
         elif isinstance(expr, fast_inv_sqrt):
-            return f"__frsqrt_rn({tuple(self._print(a) for a in expr.args)})"
+            return "__frsqrt_rn(%s)" % tuple(self._print(a) for a in expr.args)
         return super()._print_Function(expr)

pystencils_tests/test_fast_approximation.py

@@ -12,6 +12,7 @@ def test_fast_sqrt():
     assert len(insert_fast_sqrts(expr).atoms(fast_sqrt)) == 1
     assert len(insert_fast_sqrts([expr])[0].atoms(fast_sqrt)) == 1
     ast = ps.create_kernel(ps.Assignment(g[0, 0], insert_fast_sqrts(expr)), target='gpu')
+    ast.compile()
     code_str = ps.get_code_str(ast)
     assert '__fsqrt_rn' in code_str
 
@@ -21,6 +22,7 @@ def test_fast_sqrt():
     ac = ps.AssignmentCollection([expr], [])
     assert len(insert_fast_sqrts(ac).main_assignments[0].atoms(fast_inv_sqrt)) == 1
     ast = ps.create_kernel(insert_fast_sqrts(ac), target='gpu')
+    ast.compile()
     code_str = ps.get_code_str(ast)
     assert '__frsqrt_rn' in code_str
 
@@ -34,5 +36,6 @@ def test_fast_divisions():
     assert len(insert_fast_divisions(expr).atoms(fast_division)) == 1
 
     ast = ps.create_kernel(ps.Assignment(g[0, 0], insert_fast_divisions(expr)), target='gpu')
+    ast.compile()
     code_str = ps.get_code_str(ast)
     assert '__fdividef' in code_str