函数工具
any
Object any(bool Function(double) condition, {int dim = -1})
判断矩阵中是否存在满足条件的值（存在性问题）
test
import 'package:flutter_matrix/matrix_type.dart';
main() {
data_format = "%2.0f";
List<List<double>> data = [
[4, double.nan, 0, 9],
[0, 3, 1, double.infinity],
[5, 6, 3, -double.infinity],
];
var mt1 = Matrix(data);
print(mt1.any((x) => x == double.negativeInfinity, dim: 0));
print(mt1.any((x) => x == double.negativeInfinity, dim: 1));
print(mt1.any((x) => x == double.negativeInfinity, dim: 2));
}
output
[false, false, true]
[false, false, false, true]
true
all
Object all(bool Function(double) condition, {int dim = -1})
判断矩阵中数据是否全部满足条件（整体满足问题）
test
import 'package:flutter_matrix/matrix_type.dart';
main() {
data_format = "%2.0f";
List<List<double>> data = [
[4, -3, 0, 9],
[0, 3, 1, 7],
[2, 6, 82, 8],
];
var mt1 = Matrix(data);
print(mt1.any((x) => x ~/ 2 == 0, dim: 0));
print(mt1.any((x) => x ~/ 2 == 0, dim: 1));
print(mt1.any((x) => x ~/ 2 == 0, dim: 2));
}
output
[true, true, false]
[true, false, true, false]
true
reduce
Object reduce(double Function(double, double) condition, {double? element, int dim = -1})
定义归约操作，element是选择性传入的初始归约值
test
import 'package:flutter_matrix/matrix_type.dart';
main() {
data_format = "%2.0f";
var mt = Matrix.range(row: 4, column: 3, start: 1, step: 2);
mt.visible();
print(mt.reduce((x, y) => x + y, element: 10.0, dim: 0));
print(mt.reduce((x, y) => x / y, element: 1.0, dim: 1));
print(mt.reduce((x, y) => x * y, element: null, dim: 2));
}
output
[
[ 1 3 5]
[ 7 9 11]
[ 13 15 17]
[ 19 21 23]
]
[19.0, 37.0, 55.0, 73.0]
[0.000578368999421631, 0.00011757789535567314, 0.00004650081376424089]
316234143225.0
customize
Matrix customize(double Function(double) condition)
自定义映射，如有要对一个矩阵实现对数据的多次运算且需要避免多次创建，customize是一个不错的选择
test
import 'dart:math' as math;
import 'package:flutter_matrix/matrix_type.dart';
main() {
data_format = "%2.0f";
List<List<double>> data = [
[1, -3, 1, 9],
[1, 3, 1, 7],
[2, 6, -5, 8],
];
final f = (x) => math.exp(x) + math.cos(x) + x * x;
var mt1 = Matrix(data);
var y = mt1.customize(f);
var y_derivative = mt1.customize((x) => math.exp(x) - math.sin(x) + 2 * x);
y.visible();
y_derivative.visible();
mt1.diff(f).visible();
}
output
[
[ 4 8 4 8183]
[ 4 28 4 1146]
[ 11 440 25 3045]
]
[
[ 4 -6 4 8121]
[ 4 26 4 1110]
[ 10 416 -11 2996]
]
[
[ 4 -6 4 8121]
[ 4 26 4 1110]
[ 10 416 -11 2996]
]
confront
Matrix confront(double Function(double, double) condition, {required Matrix other})
实现两个矩阵对应位置上的数据之间的操作映射
test
import 'package:flutter_matrix/matrix_type.dart';
main() {
data_format = "%2.1f";
List<List<double>> data = [
[4, 1, 0, 9],
[0, 3, 1, 9],
[5, 6, 3, 2],
[1, 2, 3, 8],
];
var mt = Matrix.fromList(data);
var mt1 = Matrix.fromList([
[4, -1, 0, 9],
[0, -3, 1, 9],
[5, 6, -3, 2],
[1, 2, -3, 8],
]);
final a = mt.confront((x, y) => x + y, other: mt1)
..visible(); // Simulate addition
final b = (mt1 + mt)..visible();
print(a == b);
}
output
[
[ 8.0 0.0 0.0 18.0]
[ 0.0 0.0 2.0 18.0]
[10.0 12.0 0.0 4.0]
[ 2.0 4.0 0.0 16.0]
]
[
[ 8.0 0.0 0.0 18.0]
[ 0.0 0.0 2.0 18.0]
[10.0 12.0 0.0 4.0]
[ 2.0 4.0 0.0 16.0]
]
true
replace
void replace(bool Function(double) condition, {required double Function(double) cope})
对满足条件的值进行映射到cope函数值
test
import 'package:flutter_matrix/matrix_type.dart';
main() {
data_format = "%2.1f";
List<List<double>> data = [
[4, 1, 0, 9],
[0, 3, 1, 9],
[5, 6, 3, 2],
[1, 2, 3, 8],
];
var mt = Matrix.fromList(data)..replace((x) => x == 9 || x == 0, cope: (_) => 7);
mt.visible();
}
output
[
[ 4.0 1.0 7.0 7.0]
[ 7.0 3.0 1.0 7.0]
[ 5.0 6.0 3.0 2.0]
[ 1.0 2.0 3.0 8.0]
]
clip
Matrix clip(double Function(double) condition, {required double lb, required double ub, bool reverse = false}) 根据上下限限制的数据进行条件替换，reverse为true表示范围两侧保留，其余替换，反之范围内保留，两侧替换
test
import 'package:flutter_matrix/matrix_type.dart';
main() {
data_format = "%2.0f";
var mt = Matrix.range(row: 4, column: 6, start: 1, step: 2);
mt.visible();
mt.clip((x) => x < 3 ? 3 : x > 8 ? 8 : x, lb: 3, ub: 8, reverse: false).visible();
mt.clip((x) => 3 < x && x < 8 ? 0 : x, lb: 3, ub: 8, reverse: true).visible();
}
output
[
[ 1 3 5 7 9 11]
[ 13 15 17 19 21 23]
[ 25 27 29 31 33 35]
[ 37 39 41 43 45 47]
]
[
[ 3 3 5 7 8 8]
[ 8 8 8 8 8 8]
[ 8 8 8 8 8 8]
[ 8 8 8 8 8 8]
]
[
[ 1 3 0 0 9 11]
[ 13 15 17 19 21 23]
[ 25 27 29 31 33 35]
[ 37 39 41 43 45 47]
]
count
Object count(bool Function(double) condition, {int dim = -1})
统计满足统计值的个数
test
import 'package:collection/collection.dart';
import 'package:flutter_matrix/matrix_type.dart';
main() {
data_format = "%2.2f";
var m = MatrixRandom.uniform(row: 5, column: 5, lb: 0, ub: 1, seed: 42)..visible();
print(m.count((x) => x < 0.5, dim: 0));
print((m.count((x) => x < 0.5, dim: 0) as List<int>).sum);
print(m.count((x) => x < 0.5, dim: 1));
print((m.count((x) => x < 0.5, dim: 1) as List<int>).sum);
print(m.count((x) => x < 0.5, dim: 2));
}
output
[
[ 0.15 0.60 0.66 0.22 0.79]
[ 0.16 0.41 0.17 0.21 0.57]
[ 0.83 0.35 0.89 0.12 0.55]
[ 0.89 0.56 0.43 0.68 0.78]
[ 0.78 0.20 0.70 0.36 0.48]
]
[2, 4, 2, 1, 3]
12
[2, 3, 2, 4, 1]
12
12