给定y截距和斜率绘制线图 [英] Plotting a line in a chart given the y intercept and slope
问题描述
我编写了一个程序,计算给定用户的几个输入值的最佳拟合线(截距/斜率)。我已经绘制了每个单独的值,但不确定的代码绘制线给定的斜率和y截距。
I've written a program that calculates the line of best fit (intercept/slope) given several input values from the user. I've plotted each of the individual values, however unsure of the code to plot the line given the slope and y-intercept.
是斜率:
double m = ( aXY.Sum() -
((levels.Sum() * scores.Sum()) / 5)) / (newaX.Sum() - ((powLevels) / 5));
侦察
double b = meanY - (m * meanX);
绘制点
for (int i = 0; i < levels.GetLength(0); i++)
{
chart1.Series["Series1"].Points
.AddXY(levels.GetValue(i), scores.ToArray().GetValue(i));
}
任何想法?我不是一个专家,并得到这远远采取了一个相当多的实验。
Any ideas? I am by no means an expert and getting this far took a fair bit of experimenting..
推荐答案
假设您的数据被绘制为使用 ChartType.Points
的最简单的添加行的散点图是添加一个额外 系列
与 ChartType.Line
并设置两点。
Assuming your data are plotted as a scattergraph using the ChartType.Points
the simplest way to add a line is to add one extra Series
with ChartType.Line
and set two points there.
有是在图表
上创建线条的其他方法,或创建 LineAnnotation
,但它们很多更复杂!
There are other ways to create a line on a Chart
, like drawing it or creating a LineAnnotation
, but they are much more complicated!
href =http://hotmath.com/hotmath_help/topics/line-of-best-fit.html =nofollow noreferrer>此示例到这里的字母是一个实现:
Following this example to the letter here is an implementation:
请注意,在为行创建系列:
private void button1_Click(object sender, EventArgs e)
{
// create TWO series!
chart1.Series.Clear();
chart1.Series.Add("Data");
chart1.Series.Add("Line of best fit");
chart1.Series[0].ChartType = SeriesChartType.Point;
chart1.Series[1].ChartType = SeriesChartType.Line;
List<int> levels = new List<int>() { 8, 2, 11, 6, 5, 4, 12, 9, 6, 1};
List<int> scores = new List<int>() { 3, 10, 3, 6, 8, 12, 1, 4, 9, 14};
double minX = levels.ToList().Min();
double maxX = levels.ToList().Max();
double meanX = 1f * levels.Sum() / levels.Count;
double meanY = 1f * scores.Sum() / scores.Count;
double st = 0;
double sb = 0;
for (int i = 0; i < levels.Count; i++ )
{
st += (levels[i] - meanX) * (scores[i] - meanY);
sb += (levels[i] - meanX) * (levels[i] - meanX);
}
double slope = st / sb;
double y0 = meanY - slope * meanX; // y-intercept or y-crossing
for (int i = 0; i < levels.Count; i++)
{
chart1.Series[0].Points.AddXY(levels[i], scores[i]);
}
// this is the part that creates the line of best fit:
chart1.Series[1].Points.AddXY(minX, y0 + minX * slope);
chart1.Series[1].Points.AddXY(maxX, y0 + maxX * slope);
}
如果你愿意,可以直接在y-轴:
If you want to you can add the first line point right at the y-axis:
chart1.Series[1].Points.AddXY(0, y0 );
在这种情况下,您可能需要设置图表中显示的最小x值,包括 -1
,也许像这样:
In this case you may want to set the minimum x-values shown in the chart to prevent it from including -1
, maybe like this:
chart1.ChartAreas[0].AxisX.Minimum = minX - 1;
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