Y-axis is inverted

[jesper-olsen]

The y-axis is inverted in the mandelbrot plot on this page

https://docs.modular.com/mojo/notebooks/Mandelbrot.html

because the plot is centered on 0,0 and mandelbrot is symmetric around the x-axis, this inversion is not obvious in the plot. But it is obvious if y_max,y_min is not not centered on 0 ...

Here is a fix - update compute_mandelbrot() - like this:

fn compute_mandelbrot() -> Tensor[float_type]:
    # create a matrix. Each element of the matrix corresponds to a pixel
    var t = Tensor[float_type](height, width)

    let dx = (max_x - min_x) / width
    let dy = (max_y - min_y) / height

    #y = min_y
    var y = max_y
    for row in range(height):
        var x = min_x
        for col in range(width):
            t[Index(row, col)] = mandelbrot_kernel(ComplexFloat64(x, y))
            x += dx
        y -= dy
        #y += dy
    return t

[jesper-olsen]

Also see
#1471