Comments on: Why Does MATLAB Have the Function hypot?

By: Loren

Loren — Thu, 11 Mar 2010 17:59:36 +0000

Shahn-

You can use hypot if that is what makes sense. Here’s the help page. And here’s a few details from it:

c = hypot(a,b) returns the element-wise result of the following equation, computed to avoid underflow and overflow:

c = sqrt(abs(a).^2 + abs(b).^2)

Inputs a and b must follow these rules:

* Both a and b must be single- or double-precision, floating-point arrays.

* The sizes of the a and b arrays must either be equal, or one a scalar and the other nonscalar. In the latter case, hypot expands the scalar input to match the size of the nonscalar input.

Best wishes,
Loren

By: Shahn

Shahn — Thu, 11 Mar 2010 15:14:15 +0000

Hi Loren

I have a binary image and I want to find the distance between every object. I have already computed the centroid for every object. Can Hypot be used for many objects ???

By: Loren

Loren — Mon, 11 Feb 2008 12:54:30 +0000

Hal-

norm is also careful to scale results, like abs and hypot.

–Loren

By: Hal K

Hal K — Mon, 11 Feb 2008 10:37:35 +0000

Loren,
Does hypot(a,a) any different from norm([a a])?

Hal

By: Loren

Loren — Sat, 09 Feb 2008 02:21:52 +0000

Duane-

Thanks for pointing out that abs is also implemented robustly.

–Loren

By: Duane Hanselman

Duane Hanselman — Fri, 08 Feb 2008 15:07:00 +0000

Before hypot existed, I used a=abs(complex(a,b)); In doing so, I was able to tap the robustness of the abs() function.

By: Quan

Quan — Fri, 08 Feb 2008 00:24:19 +0000

That was a pretty interesting post Loren. I’m not sure if it will affect the way I do things around here, but it’s something that could come in useful in the future. Thanks for the tip!