/// <summary>
/// 混合处理，降采样和插值，不保留边界节点
/// </summary>
/// <param name="data">原始数据</param>
/// <param name="size">桶大小。如60/3600/86400</param>
/// <param name="offset">偏移量。时间不是对齐零点时使用</param>
/// <returns></returns>
public TimePoint[] Process(TimePoint[] data, Int32 size, Int32 offset = 0)
{
if (data == null || data.Length < 2)
{
return(data);
}
if (size <= 1)
{
return(data);
}
var xs = new Int64[data.Length];
for (var i = 0; i < data.Length; i++)
{
xs[i] = data[i].Time;
}
var buckets = SamplingHelper.SplitByFixedSize(xs, size, offset);
// 每个桶选择一个点作为代表
var sampled = new TimePoint[buckets.Length];
var last = 0;
for (var i = 0; i < buckets.Length; i++)
{
// 断层，插值
var item = buckets[i];
if (item.Start < 0)
{
// 取last用于插值起点，如果不存在，可以取0点
// 此时End指向下一个有效点，即使下一个桶也是断层
sampled[i].Time = i * size;
sampled[i].Value = Interpolation.Process(data, last, item.End, i);
continue;
}
TimePoint point = default;
var vs = 0.0;
for (var j = item.Start; j < item.End; j++)
{
vs += data[j].Value;
}
last = item.End - 1;
point.Value = vs / (item.End - item.Start);
// 对齐
point.Time = AlignMode switch
{
AlignModes.Right => (i + 1) * size - 1,
AlignModes.Center => data[(Int32)Math.Round((i + 0.5) * size)].Time,
_ => i * size,
};
sampled[i] = point;
}
return(sampled);
}
/// <summary>
/// 降采样处理
/// </summary>
/// <param name="data">原始数据</param>
/// <param name="threshold">阈值，采样数</param>
/// <returns></returns>
public TimePoint[] Down(TimePoint[] data, Int32 threshold)
{
if (data == null || data.Length < 2)
{
return(data);
}
if (threshold < 2 || threshold >= data.Length)
{
return(data);
}
var buckets = SamplingHelper.SplitByAverage(data.Length, threshold, true);
// 每个桶选择一个点作为代表
var sampled = new TimePoint[buckets.Length];
for (var i = 0; i < buckets.Length; i++)
{
var item = buckets[i];
TimePoint point = default;
var min_value = Double.MaxValue;
for (var j = item.Start; j < item.End; j++)
{
if (data[j].Value < min_value)
{
min_value = data[j].Value;
point = data[j];
}
}
// 对齐
switch (AlignMode)
{
case AlignModes.Left:
point.Time = data[item.Start].Time;
break;
case AlignModes.Right:
point.Time = data[item.End - 1].Time;
break;
case AlignModes.Center:
point.Time = data[(Int32)Math.Round((item.Start + item.End) / 2.0)].Time;
break;
}
sampled[i++] = point;
}
// 第一个点和最后一个点
if (AlignMode == AlignModes.None)
{
sampled[0] = data[0];
sampled[threshold - 1] = data[data.Length - 1];
}
return(sampled);
}
/// <summary>
/// 降采样处理
/// </summary>
/// <param name="data">原始数据</param>
/// <param name="threshold">阈值，采样数</param>
/// <returns></returns>
public TimePoint[] Down(TimePoint[] data, Int32 threshold)
{
if (data == null || data.Length < 2)
{
return(data);
}
if (threshold < 2 || threshold >= data.Length)
{
return(data);
}
var buckets = SamplingHelper.SplitByAverage(data.Length, threshold, true);
// 每个桶选择一个点作为代表
var sampled = new TimePoint[buckets.Length];
for (var i = 0; i < buckets.Length; i++)
{
var item = buckets[i];
TimePoint point = default;
var vs = 0.0;
for (var j = item.Start; j < item.End; j++)
{
vs += data[j].Value;
}
point.Value = vs;
// 对齐
switch (AlignMode)
{
case AlignModes.Left:
default:
point.Time = data[item.Start].Time;
break;
case AlignModes.Right:
point.Time = data[item.End - 1].Time;
break;
case AlignModes.Center:
point.Time = data[(Int32)Math.Round((item.Start + item.End) / 2.0)].Time;
break;
}
sampled[i] = point;
}
return(sampled);
}
/// <summary>
/// 降采样处理
/// </summary>
/// <param name="data">原始数据</param>
/// <param name="threshold">阈值，采样数</param>
/// <returns></returns>
public TimePoint[] Down(TimePoint[] data, Int32 threshold)
{
if (data == null || data.Length < 2)
{
return(data);
}
if (threshold < 2 || threshold >= data.Length)
{
return(data);
}
var buckets = SamplingHelper.SplitByAverage(data.Length, threshold, AlignMode == AlignModes.None);
// 三角形选择当前同相邻三个ABC点，选择B，使得三角形有效面积最大
var sampled = new TimePoint[buckets.Length];
for (var i = 0; i < buckets.Length; i++)
{
var item = buckets[i];
// 计算每个点的有效区域，并选取有效区域最大的点作为桶的代表点
TimePoint point = default;
var max_area = -1.0;
for (var j = item.Start + 1; j < item.End - 1; j++)
{
// 选择一个点B，计算ABC三角形面积
var pointA = data[j - 1];
var pointB = data[j];
var pointC = data[j + 1];
var area = Math.Abs(
(pointA.Time - pointC.Time) * (pointB.Value - pointA.Value) -
(pointA.Time - pointB.Time) * (pointC.Value - pointA.Value)
) / 2;
if (area > max_area)
{
max_area = area;
point = pointB;
}
}
// 对齐
switch (AlignMode)
{
case AlignModes.Left:
point.Time = data[item.Start].Time;
break;
case AlignModes.Right:
point.Time = data[item.End - 1].Time;
break;
case AlignModes.Center:
point.Time = data[(Int32)Math.Round((item.Start + item.End) / 2.0)].Time;
break;
}
sampled[i++] = point;
}
// 第一个点和最后一个点
if (AlignMode == AlignModes.None)
{
sampled[0] = data[0];
sampled[threshold - 1] = data[data.Length - 1];
}
return(sampled);
}
/// <summary>
/// 混合处理，降采样和插值
/// </summary>
/// <param name="data">原始数据</param>
/// <param name="size">桶大小。如60/3600/86400</param>
/// <param name="offset">偏移量。时间不是对齐零点时使用</param>
/// <returns></returns>
public TimePoint[] Process(TimePoint[] data, Int32 size, Int32 offset = 0)
{
if (data == null || data.Length < 2)
{
return(data);
}
if (size <= 1)
{
return(data);
}
var xs = new Int64[data.Length];
for (var i = 0; i < data.Length; i++)
{
xs[i] = data[i].Time;
}
var buckets = SamplingHelper.SplitByFixedSize(xs, size, offset);
// 每个桶选择一个点作为代表
var sampled = new TimePoint[buckets.Length];
var last = 0;
for (var i = 0; i < buckets.Length; i++)
{
// 断层，插值
var b = buckets[i];
if (b.Start < 0)
{
sampled[i].Time = i * size;
sampled[i].Value = Interpolation.Process(data, last, b.End, i);
continue;
}
TimePoint point = default;
var vs = 0.0;
for (var j = b.Start; j < b.End; j++)
{
vs += data[j].Value;
}
last = b.End - 1;
point.Value = vs / (b.End - b.Start);
// 对齐
switch (AlignMode)
{
case AlignModes.Left:
default:
point.Time = i * size;
break;
case AlignModes.Right:
point.Time = (i + 1) * size - 1;
break;
case AlignModes.Center:
point.Time = data[(Int32)Math.Round((i + 0.5) * size)].Time;
break;
}
sampled[i] = point;
}
return(sampled);
}
/// <summary>
/// 降采样处理
/// </summary>
/// <param name="data">原始数据</param>
/// <param name="threshold">阈值，采样数</param>
/// <returns></returns>
public TimePoint[] Down(TimePoint[] data, Int32 threshold)
{
if (data == null || data.Length < 2)
{
return(data);
}
if (threshold < 2 || threshold >= data.Length)
{
return(data);
}
var buckets = SamplingHelper.SplitByAverage(data.Length, threshold, AlignMode == AlignModes.None);
// 三角形选择相邻三个桶的ABC点，A是前一个桶选择点，C是后一个桶平均点，当前桶选择B，使得三角形有效面积最大
TimePoint pointA = default;
if (AlignMode == AlignModes.None)
{
pointA = data[0];
}
var sampled = new TimePoint[buckets.Length];
for (var i = 0; i < buckets.Length; i++)
{
var item = buckets[i];
// 计算下一个桶的平均点作为C
TimePoint pointC = default;
{
var start = buckets[i + 1].Start;
var end = buckets[i + 1].End;
end = end < data.Length ? end : data.Length;
var length = end - start;
for (; start < end; start++)
{
pointC.Time += data[start].Time;
pointC.Value += data[start].Value;
}
if (length > 0)
{
pointC.Time /= length;
pointC.Value /= length;
}
else
{
pointC = data[end - 1];
}
}
// 计算每个点的有效区域，并选取有效区域最大的点作为桶的代表点
TimePoint point = default;
{
var max_area = -1.0;
for (var j = item.Start; j < item.End; j++)
{
// 选择一个点B，计算ABC三角形面积
var pointB = data[j];
var area = Math.Abs(
(pointA.Time - pointC.Time) * (pointB.Value - pointA.Value) -
(pointA.Time - pointB.Time) * (pointC.Value - pointA.Value)
) / 2;
if (area > max_area)
{
max_area = area;
point = pointB;
}
}
}
pointA = point;
// 对齐
switch (AlignMode)
{
case AlignModes.Left:
point.Time = data[item.Start].Time;
break;
case AlignModes.Right:
point.Time = data[item.End - 1].Time;
break;
case AlignModes.Center:
point.Time = data[(Int32)Math.Round((item.Start + item.End) / 2.0)].Time;
break;
}
sampled[i++] = point;
}
// 第一个点和最后一个点
if (AlignMode == AlignModes.None)
{
sampled[0] = data[0];
sampled[threshold - 1] = data[data.Length - 1];
}
return(sampled);
}
