Fuse thread safety check with existing check

src/pystencils/config.py

@@ -135,14 +135,9 @@ class CreateKernelConfig:
     """
     skip_independence_check: bool = False
     """
-    Don't check that loop iterations are independent. This is needed e.g. for
-    periodicity kernel, that access the field outside the iteration bounds. Use with care!
-    """
-    check_thread_safety: bool = True
-    """
-    Assignments are considered thread safe if read and writes only target the same locations. If this is not the case,
-    multithreaded optimisations will fail. The thread safety check can be deactivated to use e.g. GPUs anyway.
-    Use with care!
+    By default the assignment list is checked for read/write independence. This means fields are only written at
+    locations where they are read. Doing so guarantees thread safety. In some cases e.g. for
+    periodicity kernel, this can not be assured and does the check needs to be deactivated. Use with care!
     """
 
     class DataTypeFactory:

src/pystencils/kernel_contrains_check.py

@@ -43,7 +43,6 @@ class KernelConstraintsCheck:
         self.fields_read = set()
         self.check_independence_condition = check_independence_condition
         self.check_double_write_condition = check_double_write_condition
-        self.thread_safe = True
 
     def visit(self, obj):
         if isinstance(obj, (AssignmentCollection, NodeCollection)):
@@ -117,7 +116,9 @@ class KernelConstraintsCheck:
             if fai in self.field_reads:
                 reads = tuple(self.field_reads[fai])
                 if len(reads) > 1 or lhs.offsets != reads[0]:
-                    self.thread_safe = False
+                    if self.check_independence_condition:
+                        raise ValueError(f"Field {lhs.field.name} is written at different location than it was read. "
+                                         f"This means the resulting kernel would not be thread safe")
         elif isinstance(lhs, sp.Symbol):
             if self.scopes.is_defined_locally(lhs):
                 raise ValueError(f"Assignments not in SSA form, multiple assignments to {lhs.name}")

src/pystencils/kernelcreation.py

@@ -130,12 +130,6 @@ def create_domain_kernel(assignments: NodeCollection, *, config: CreateKernelCon
                                    check_double_write_condition=not config.allow_double_writes)
 
     check.visit(assignments)
-    if not check.thread_safe and config.check_thread_safety:
-        base = "Assignments are not thread safe because data is read and written on different locations."
-        if config.cpu_openmp:
-            raise ValueError(f"{base} OpenMP optimisation is not permitted in this scenario.")
-        if config.target == Target.GPU:
-            raise ValueError(f"{base} GPU target is not permitted in this case, only CPU target with single thread")
 
     assignments.bound_fields = check.fields_written
     assignments.rhs_fields = check.fields_read