似乎C#在添加两个UInt16 []数组时比在添加两个int []数组时更快.这对我来说没有意义,因为我会假设数组是字对齐的,因此int []需要较少的cpu工作,不是吗？
我运行了下面的测试代码,得到了以下结果：
Int for 1000 took 9896625613 tick (4227 msec) UInt16 for 1000 took 6297688551 tick (2689 msec)
测试代码执行以下操作：
>创建两个名为a和b的数组,一次.
>用随机数据填充一次.
>启动秒表.
>逐项添加a和b.这样做了1000次.
>停止秒表.
>报告花了多长时间.
这是针对int [] a,b和UInt16 a,b完成的.每次运行代码时,UInt16阵列的测试时间比int数组少30％-50％.你能解释一下吗？
这是代码,如果你想尝试自己：
public static UInt16[] GenerateRandomDataUInt16(int length)
{
UInt16[] noise = new UInt16[length];
Random random = new Random((int)DateTime.Now.Ticks);
for (int i = 0; i < length; ++i)
{
noise[i] = (UInt16)random.Next();
}
return noise;
}
public static int[] GenerateRandomDataInt(int length)
{
int[] noise = new int[length];
Random random = new Random((int)DateTime.Now.Ticks);
for (int i = 0; i < length; ++i)
{
noise[i] = (int)random.Next();
}
return noise;
}
public static int[] AddInt(int[] a,int[] b)
{
int len = a.Length;
int[] result = new int[len];
for (int i = 0; i < len; ++i)
{
result[i] = (int)(a[i] + b[i]);
}
return result;
}
public static UInt16[] AddUInt16(UInt16[] a,UInt16[] b)
{
int len = a.Length;
UInt16[] result = new UInt16[len];
for (int i = 0; i < len; ++i)
{
result[i] = (ushort)(a[i] + b[i]);
}
return result;
}
public static void Main()
{
int count = 1000;
int len = 128 * 6000;
int[] aInt = GenerateRandomDataInt(len);
int[] bInt = GenerateRandomDataInt(len);
Stopwatch s = new Stopwatch();
s.Start();
for (int i=0; i<count; ++i)
{
int[] resultInt = AddInt(aInt,bInt);
}
s.Stop();
Console.WriteLine("Int for " + count
+ " took " + s.ElapsedTicks + " tick ("
+ s.ElapsedMilliseconds + " msec)");
UInt16[] aUInt16 = GenerateRandomDataUInt16(len);
UInt16[] bUInt16 = GenerateRandomDataUInt16(len);
s = new Stopwatch();
s.Start();
for (int i=0; i<count; ++i)
{
UInt16[] resultUInt16 = AddUInt16(aUInt16,bUInt16);
}
s.Stop();
Console.WriteLine("UInt16 for " + count
+ " took " + s.ElapsedTicks + " tick ("
+ s.ElapsedMilliseconds + " msec)");
}
