Hey again esteemed Monks,

I've got yet another mathematical question which once again, should be quite easy.

I'm adding a digital potentiometer to my Raspberry Pi CI unit test platform. This pot has 256 taps (0-255). (If you're unsure what a potentiometer is, imagine in the old days where you had to turn up/down your radio volume with a knob).

For my tests, I'm looking to normalize the 256 taps to a value between 0 and 100 (percent). I've been looking online to sort this out and I'm sure I've got it, but there are so many answers, I thought I'd reach out here to ensure things appear correct:

use warnings;
use strict;

use feature 'say';

my ($min, $max) = (0, 255);
my ($new_min, $new_max) = (0, 100);

for my $tap ($min .. $max){
    my $x = (($tap - $min) * ($new_max - $new_min) / ($max - $min));
    say "$tap: $x";
}

[download]

Output:

0: 0
1: 0.392156862745098
2: 0.784313725490196
3: 1.17647058823529

...

127: 49.8039215686275
128: 50.1960784313725
129: 50.5882352941176

...

252: 98.8235294117647
253: 99.2156862745098
254: 99.6078431372549
255: 100

[download]

It appears perfectly good to me for what I need it for, but just would like some reassurance, so that if I use this calculation in the future, I won't be wondering what may be wrong.

When I'm testing variable outputs from such Integrated Circuits (pots, digital to analog converters etc), I want to set up a normalized number range and test each point (within a 1-2% boundary) instead of jumping chunks using AoAs for the data ranges to test against, like I do here.

Do my calculations within the code resonate well?

In reply to Normalizing a range of numbers to a percentage by stevieb

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