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Talk:Numeric error propagation: Difference between revisions
→Not sure how to do this: why id()?
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:They should be treated as independent for the purposes of this task, but see the Python solution where I have added a check for an object being multiplied by itself, which means having the same id() in Python (implemented as a check on the memory location occupied by an object in C-Python). --[[User:Paddy3118|Paddy3118]] 18:19, 31 July 2011 (UTC)
:: Don't do that. This is the same question as the one I asked above about correlations. For a variable, you either track all its error sources for correctness, or track none for simplicity. Checking just one source is good for neither. Consider:<lang>a.value = 10
a.error = 1.0
b := a * 2
c := a - b</lang>How do you deal with the error at assignment of c and d? Checking memory location isn't enough. If a variable has full error source information, a and b would have the same source of error but with different magnitude, so c.error == a.error, but a and b won't have the same mem location so you probably would think c.error = a.error * sqrt(5). Checking identifier equality is not much more correct than tracking nothing, but more confusing and less consistent. --[[User:Ledrug|Ledrug]] 20:20, 31 July 2011 (UTC)
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