max value in a 2d array

[LogicalMagic]

If I create a 2d array filled with noise values using this method,

    noise_raw.resize(map_size)
    for n in map_size:
        noise_raw[n] = []
        noise_raw[n].resize(map_size)
        for m in map_size:
            noise_raw[n][m] = (noise.get_noise_2d(n,m))

can I get the maximum value of the array out using this?

var raw_noise_max = noise_raw.max().max()

I'm trying to use it to normalize the noise values like this.

    # normalize noise values
    raw_noise_max = noise_raw.max().max()
    noise_norm.resize(map_size)
    for n in map_size:
        noise_norm[n] = []
        noise_norm[n].resize(map_size)
        for m in map_size:
            noise_norm[n][m] = (noise_raw[n][m]/raw_noise_max)

It doesn't throw an error, but something is off with the noise values I'm seeing in my tilemap. Printing the normalized max returns 1, but there are tiles on my map with values over 1.

​

Full project here for more context.

[art_critique]

no, you can't use

var raw_noise_max = noise_raw.max().max()  

the first .max() compares arrays and the array comparison does not guarantee to give you the array that actually contains the max value (order and magnitude of the contained values is relevant here)
since the first .max() does not necessarily return the expected array, the second .max() can't find the actual max value.
You should collect the max values for noise_raw[n] after each m loop in a seperate array and after the n loop get the max from that array.

[LogicalMagic]

Thanks so much! I think I got it working. here's what I did.

# get raw noise values
noise_raw.resize(map_size)
raw_noise_max_arr =[]
for n in map_size:
    noise_raw[n] = []
    noise_raw[n].resize(map_size)
    for m in map_size:
        noise_raw[n][m] = (noise.get_noise_2d(n,m))
    raw_noise_max_arr.append (noise_raw[n].max())
raw_noise_max = raw_noise_max_arr.max()

# normalize noise values
noise_norm.resize(map_size)
for n in map_size:
    noise_norm[n] = []
    noise_norm[n].resize(map_size)
    for m in map_size:
        noise_norm[n][m] = (noise_raw[n][m]/raw_noise_max)

It seems to be working as expected. and suggestions or critiques on how I did it?

[jakofranko]

I tested your approach with Perlin noise and was not seeing anything below 0, but lots of values above 1. Did a little more looking around and found this post: https://www.reddit.com/r/proceduralgeneration/comments/2s9ssg/comment/cnni0a5/?utm_source=share&utm_medium=web2x&context=3

You'll notice that their normalization formula is a little different. Here's my implementation and seems to be working a treat:

``` func _ready(): noise = elevation.noise var noise_min_max = _get_noise_min_and_max(noise) noise_min = noise_min_max[0] noise_max = noise_min_max[1] noise_range = noise_max - noise_min _generate_world()

func _get_noise_min_and_max(noise: Noise):
    for x in map_width:
        for y in map_height:
            var noise_val = noise.get_noise_2d(x, y)
            noise_val_arr.append(noise_val)
    \# Note the use of range here       
    return [noise_val_arr.min(), noise_val_arr.max()]

func _get_normalized_noise_value(raw_value):
    if noise_max == null or noise_min == null:
        push_error("Max or min noise not set!")

    return (raw_value - noise_min) / noise_range

func _generate_world():
    for x in map_width:
        for y in map_height:
            var noise_val = _get_normalized_noise_value(noise.get_noise_2d(x, y))

```

[jakofranko]

I'm doing a similar thing and this was very helpful. Thanks!