Compare Pastes

Differences between the pastes #162878 (31.01.2021 14:42) and #276991 (27.08.2024 23:38).
1
import std.stdio;
2
3
extern(C) __gshared string[] rt_options =

4
    [ "gcopt=minPoolSize:2K maxPoolSize:1M incPoolSize:4K" ];

5
6
auto fastAbs(float x) @system

7
{

8
	uint p = *(cast(uint*) &x);

9
	p &=0x7fffffff;

10
	return *(cast(float*) &p);

11
}

12
13
auto renormalize(Range)(Range r)

14
{

15
	import std.algorithm;

16
17
	auto maximalAbsoluteValue = r

18
								.map!(a => fastAbs(a))

19
								.fold!max;

20
	return r

21
			.map!(a => a / maximalAbsoluteValue);

22
}

23
24
void main()

25
{

26
	import std.algorithm;

27
	import std.complex;

28
	import std.math;

29
	import std.numeric;

30
	import std.random;

31
	import std.range;

32
33
	import ppmformats;

34
35
	auto rng = Random(unpredictableSeed);

36
37
	auto signalWithNoise(float x)

38
	{

39
		return (3.3 * sin(2*x)) + uniform(-0.3, 0.3, rng);

40
	}

41
	

42
	alias squareWave = delegate(float x) {

43
	  return

44
          ((4 * 10) / (PI)) * (sin(x) + (sin(3 * x) / (3 * x)) + (sin(5 * x) /(5 * x)) + (sin(7 * x) / (7 * x)) + (sin(9 * x) / (9 * x)) + (sin(11 * x) / (11 * x))) + (sin(13 * x) / (13 * x)) + (sin(15 * x) / (15 * x)) + (sin(17 * x) / (17 * x));

45
	};

46
47
	auto signal = iota(0, 2_048)

48
						.map!squareWave;

49
50
	auto normalizedFFT(Range)(Range r)

51
	{

52
		return 

53
				r

54
				  .fft

55
				  .map!(a => 20.0f * log10(abs(a ^^ 2)))

56
				  .renormalize;

57
	}

58
59
	auto pd = signal

60
					.slide(1_024)

61
					.map!(a => normalizedFFT(a));

62
63
	auto img = new P6Image(1024, 1024);

64
65
	foreach (i, e; pd.enumerate)

66
	{

67
		foreach (j, s; e.enumerate)

68
		{

69
			img[i, j] = new RGBColor(

70
				cast(int) (0.8 * 255.0 * abs(s)),

71
				0,

72
				255 - cast(int) (255 * abs(s))

73
			);

74
		}

75
	}

76
	img.save(`fft.ppm`);		

77
}