/// <summary>
/// 两个Tensor相乘，结果返回为新的Tensor。
/// 目前仅支持scalar、vector、matrix的乘法
/// </summary>
/// <param name="a">Tensor1</param>
/// <param name="b">Tensor2</param>
/// <returns>包含结果的新的Tensor</returns>
public static TensorOld Multiple(TensorOld a, TensorOld b)
{
if (a.ElementCount == 1)
{
return(Multiple(b, a.GetValue()));
}
if (b.ElementCount == 1)
{
return(Multiple(a, b.GetValue()));
}
if (a.Rank == 1)
{
a = a.Reshape(1, a.ElementCount);
}
if (b.Rank == 1)
{
b = b.Reshape(b.ElementCount, 1);
}
CheckMultipleShape(a, b);
var result = new TensorOld(a.shape[0], b.shape[1]);
Multiple(a, b, result);
return(result);
}
/// <summary>
/// 分类问题中产生的如果是概率，需要把概率转换为编码结果
/// 后面再解码得到最终的分类
/// </summary>
/// <param name="probability">概率</param>
/// <param name="code">编码</param>
public static void ProbabilityToCode(TensorOld probability, TensorOld code)
{
if (probability.Rank == 1)
{
probability = probability.Reshape(1, probability.ElementCount);
}
if (probability.Rank != 2)
{
throw new Exception("to do codec, Rank must be 2");
}
if (probability.shape[1] == 1)
{
TensorOld.Apply(probability, code, a => a > 0.5 ? 1 : 0);
}
else
{
var buff = new double[probability.shape[1]];
for (int i = 0; i < probability.shape[0]; i++)
{
probability.GetByDim1(i, buff);
ComputeCode(buff);
Array.Copy(buff, 0, code.GetRawValues(), i * buff.Length, buff.Length);
}
}
}