Add l1_norm() for Signed #43
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#38 pointed out that norm() already exists for the complex norm, which is also the absolute value.
src/lib.rs
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| @@ -434,6 +434,12 @@ impl<T: Clone + FloatCore> Complex<T> { | |||
| pub fn is_normal(self) -> bool { | |||
| self.re.is_normal() && self.im.is_normal() | |||
| } | |||
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| /// Absolute value `re + im`. | |||
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That looks like the Manhattan distance from the origin, which is quite a different thing!
If you really want this, we could add it under a more specific name, though I would also choose T: Signed since it doesn't really need floating point at all.
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Would norm_1 be more ideal?
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Hmm, do you have any precedent for that? I might suggest l1_norm, but l and 1 are visually confusing in many fonts.
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Not really, I'm no mathematician. I'm fine with l1_norm, I know in fortran they call it scabs1. I'm not really sure whats the right name is and don't really have any objection.
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Oh, now I see your edit also calling this 1-norm. Flipping that to norm_1 seems a little weird though. I'd like to know what other programming languages/libraries call this.
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For a quick sample, it seems numpy, julia, and matlab all take an ord parameter to norm. I don't want a breaking change to our existing method though.
scalar_abs might be a modern take on fortran's scabs1. But if you're OK with it, l1_norm is more consistent with the existing norm. We can clarify that it's an "L1 norm" in the docs.
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I've updated the pr and change the title accordingly to the name change to |
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bors r+ |
43: Add l1_norm() for Signed r=cuviper a=Schultzer Hi, This adds the abs method for the FloatCore trait. as far as I understand it there is no way to get the absolute value/norm of a complex number using no_std. with this method it should be possible to get absolute value with no_std. let me know if you fine with the name abs() or want it to be norm() as pointed out in #38 The motivation is to be able to make https://github.com/schultzer/blas-rs compile with no_std. /edit This is actually ["The 1-norm is simply the sum of the absolute values of the columns"](https://en.wikipedia.org/wiki/Norm_(mathematics)) Co-authored-by: Benjamin Schultzer <benjamin@schultzer.com> Co-authored-by: Josh Stone <cuviper@gmail.com>
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Hi,
This adds the abs method for the FloatCore trait.
as far as I understand it there is no way to get the absolute value/norm of a complex number using no_std. with this method it should be possible to get absolute value with no_std.
let me know if you fine with the name abs() or want it to be norm() as pointed out in #38
The motivation is to be able to make https://github.com/schultzer/blas-rs compile with no_std.
/edit
This is actually "The 1-norm is simply the sum of the absolute values of the columns"