Menu
I am looking for a library that provides a 'value with error' (eg x ± y). But searching for "Haskell xyz Error" only gives error handling libraries.
I would expect that such a library would provide common math operations (Num, Floating) where appropriate. The use case would be to get a error estimate from a calculation based on noisy sensor readings.
I did some research and the term "propagation of uncertainty" came up. I found uncertainly-haskell which I'll try out soon. Are there other packages like this?
222
If we identify an error, we remove it. Thus, we don't handle errors, we simply fix them. In Haskell, we have error and undefined to cause such errors and terminate execution of the program. On the other hand, an exception is something that can go wrong or that simply doesn't follow a rule but can happen.
There are three different ways exceptions can be thrown in Haskell: Synchronously thrown: an exception is generated from IO code and thrown inside a single thread. Asynchronously thrown: an exception is thrown from one thread to another thread to cause it to terminate early.
Strictly speaking, Either cannot be a monad, as it has kind Type -> Type -> Type ; Either String can be (and is), because it has kind Type -> Type .
Have a look at the intervals package.
90
The Data.Eq.Approximate module seems to be a fit for getting approximate equality.
Data.Eq.Approximate
Contents Type wrappers Classes for tolerance type annotations Absolute tolerance Relative tolerance Zero tolerance Tolerance annotations using Digits The purpose of this module is to provide newtype wrapper that allows one to effectively override the equality operator of a value so that it > is approximate rather than exact. For example, the type
type ApproximateDouble = AbsolutelyApproximateValue (Digits Five) Double defines an alias for a wrapper containing Doubles such that two doubles are equal if they are equal to within five decimals of accuracy; for > example, we have that
1 == (1+10^^(-6) :: ApproximateDouble) evaluates to True. Note that we did not need to wrap the value 1+10^^(-6) since AbsolutelyApproximateValue is an instance of Num. For > convenience, Num as well as many other of the numerical classes such as Real and Floating have all been derived for the wrappers defined in > this package so that one can conveniently use the wrapped values in the same way as one would use the values themselves.
Two kinds of wrappers are provided by this package.
37
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
