normal
A simple library for working with the normal probability distribution.
Usage
A simple usage example:
import "package:normal/normal.dart";
main() {
// Probability density function.
print("\nNormal.pdf\n----------\n");
for (final x in List.generate(14, (i) => (i - 6) / 2)) {
final p = Normal.pdf(x);
print(
"${x.toString().padLeft(4)} |${" " * (p * 30).round()}:${p.toStringAsFixed(4)}");
}
// Cumulative density function.
print("\nNormal.cdf\n----------\n");
for (final x in List.generate(14, (i) => (i - 6) / 2)) {
final p = Normal.cdf(x);
print(
"${x.toString().padLeft(4)} |${" " * (p * 40).round()}:${p.toStringAsFixed(4)}");
}
// Quantile function.
print("\nNormal.inverseCdf\n-----------------\n");
for (final p in List.generate(9, (i) => (i + 1) * 0.1)) {
final x = Normal.inverseCdf(p);
print("${p.toStringAsFixed(1)}\t${x.toStringAsFixed(4).padLeft(7)}");
}
// Generate random numbers.
print("\nNormal.generate\n---------------\n");
for (final x in Normal.generate(10, seed: 0)) {
print(x.toStringAsFixed(4).padLeft(7));
}
}
Output:
Normal.pdf
----------
-3.0 |:0.0044
-2.5 | :0.0175
-2.0 | :0.0540
-1.5 | :0.1295
-1.0 | :0.2420
-0.5 | :0.3521
0.0 | :0.3989
0.5 | :0.3521
1.0 | :0.2420
1.5 | :0.1295
2.0 | :0.0540
2.5 | :0.0175
3.0 |:0.0044
3.5 |:0.0009
Normal.cdf
----------
-3.0 |:0.0013
-2.5 |:0.0062
-2.0 | :0.0228
-1.5 | :0.0668
-1.0 | :0.1587
-0.5 | :0.3085
0.0 | :0.5000
0.5 | :0.6915
1.0 | :0.8413
1.5 | :0.9332
2.0 | :0.9772
2.5 | :0.9938
3.0 | :0.9987
3.5 | :0.9998
Normal.inverseCdf
-----------------
0.1 -1.2817
0.2 -0.8415
0.3 -0.5240
0.4 -0.2529
0.5 -0.0000
0.6 0.2529
0.7 0.5240
0.8 0.8415
0.9 1.2817
Normal.generate
---------------
0.4679
-0.4057
-0.2936
-1.2753
0.1079
-0.5593
0.2815
-0.1063
0.6585
0.7765
Features and bugs
Thanks for your interest in normal. Please submit any issues you encounter.