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Check legality of symbolic derivatives #1578
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- changed the title
[-]Check legaly of symbolic derivatives[/-][+]Check legality of symbolic derivatives[/+]on Feb 18, 2021 @FabioLuporini, as far as I understood the problem, we could just check
deriv_orderandspace_orderinevaluateofDerivative. The only thing I'm still figuring out is whenspacer_orderorderiv_orderis tuple. I'm not sure if this solution has the depth proposed by your hint. Let me know. By the way you mean DSE layer, right?We could check it in
evaluateor__new__ofDerivative:@property def evaluate(self): # Evaluate finite-difference. # Note: evaluate and _eval_fd splitted for potential future different # types of discretizations. do = self.deriv_order if isinstance(do,int): do = (do,) for i, d in enumerate(self.dims): expr_order = self.expr.time_order if d.is_Time else self.expr.space_order if do[i] > expr_order: raise ValueError("Expression order must be equal or greater than " "Derivative order") return self._eval_fd(self.expr)
Here is the MFE I'm testing. If any of the functions have space or time order lower than derivative, the patch will get it.
from devito import (Grid, TimeFunction, Eq, Operator) grid = Grid(tuple([11]*2)) u = TimeFunction(name="u", grid=grid, space_order=2, time_order=2) m = TimeFunction(name="m", grid=grid, space_order=1, time_order=1) # op = Operator(Eq(u.forward,u.biharmonic(1/m))) # op = Operator(Eq(u.forward,(u * m).dx2)) op = Operator(Eq(u.forward,(u * m).dt2)) op.apply(time=0)
- added a commit that references this issue
on Feb 24, 2021 - added a commit that references this issue
on Mar 22, 2021 this was fixed several months by this commit: cf85b06
hence, closing
For example, if we do:
and
mwas not initialized with "sufficient" space order, then OOB accesses will be generated, and segfaults will happenhow to fix: make sure in the DSL layer we always check that we're not applying differential operators to arguments that would result in illegal code