public Functional.Function StandardAssembler_Sqrt(ref List <string> param, ref List <string> paramexp)
{
if (paramexp.Count == 1)
{
string s = paramexp[0];
int cs = Expression.ClassOf(ref s);
if (2 <= cs && cs <= 5)
{
Functional.Function fparam = AssembleFunction(s, ref param);
return
(delegate(Tensor x)
{
return MathT.Sqrt(fparam(x));
});
}
}
throw new Exception("组装Sqrt函数失败：参数个数不合法");
}
/*public Functional.Function StandardAssembler_Average(ref List<string> param, ref List<string> paramexp)
* {
* //if(param)
* }*/
public Functional.Function StandardAssembler_MatrixDet(ref List <string> param, ref List <string> paramexp)
{
if (paramexp.Count == 1)
{
string s = paramexp[0];
int cs = Expression.ClassOf(ref s);
if (cs == 4)
{
Functional.Function fparam = AssembleFunction(paramexp[0], ref param);
return
(delegate(Tensor x)
{
Tensor ans = fparam(x);
return MathT.MatrixDet(ans);
});
}
}
throw new Exception("组装MatrixDet函数失败：参数不合法");
}
public Functional.Function StandardAssembler_Pow(ref List <string> param, ref List <string> paramexp)
{
if (paramexp.Count == 2)
{
string s = paramexp[0];
int cs1 = Expression.ClassOf(ref s);
s = paramexp[1];
int cs2 = Expression.ClassOf(ref s);
if (cs1 >= 2 && cs1 < 6 && cs2 >= 2 && cs2 < 6)
{
Functional.Function fparam1 = AssembleFunction(paramexp[0], ref param);
Functional.Function fparam2 = AssembleFunction(paramexp[1], ref param);
return
(delegate(Tensor x)
{
return MathT.Pow(fparam1(x), fparam2(x));
});
}
}
throw new Exception("组装Pow函数失败：参数不合法");
}
/// <summary>
/// 对给定的表达式，组装一个函数
/// </summary>
/// <param name="exp"></param>
/// <param name="param"></param>
/// <returns></returns>
public Functional.Function AssembleFunction(string exp, ref List <string> param)
{
string s;
switch (Expression.ClassOf(ref exp))
{
case 0: //组装一个张量
List <string> things = new List <string>();
if (!Expression.SplitList(ref exp, ref things))
{
throw new Exception("组装" + exp + "时发生错误" + "列表元素不合法");
}
List <Functional.Function> thingsfun = new List <Functional.Function>();
for (int i = 0; i < things.Count; i++) //对每个分量逐个组装
{
thingsfun.Add(AssembleFunction(things[i], ref param));
}
return
(delegate(Tensor x)
{
Tensor[] ts = new Tensor[thingsfun.Count];
for (int i = 0; i < ts.Length; i++)
{
ts[i] = thingsfun[i](x);
}
return Tensor.FromTensors(ts);
});
case 1:
//直接出现的方程和不等式，不能组装成函数
throw new Exception("");
case 2: //当前要组装一个多项式
List <string> Items = new List <string>();
Expression.SplitPolynomial(ref exp, ref Items);
List <Functional.Function> ItemsFun = new List <Functional.Function>();
for (int i = 0; i < Items.Count; i++) //对每个项逐个组装成函数
{
s = Items[i];
ItemsFun.Add(AssembleFunction(Items[i], ref param));
}
//用Lambda表达式，将每个项相加，组装
return(delegate(Tensor x)
{
Tensor ans = ItemsFun[0](x); for (int j = 1; j < ItemsFun.Count; j++)
{
ans += ItemsFun[j](x);
}
return ans;
});
case 3: //当前要组装一个项
int si = 0;
double t = 1;
//处理前导负号
while (true)
{
if (exp[si] == '-')
{
t *= -1;
}
else if (exp[si] != '+')
{
break;
}
si++;
}
string sexp = exp.Substring(si);
List <string> Factors = new List <string>();
Expression.SplitItem(ref sexp, ref Factors);
List <Functional.Function> FactorsFun = new List <Functional.Function>();
for (int i = 0; i < Factors.Count; i++) //对每个因子逐个组装成函数
{
s = Factors[i];
FactorsFun.Add(AssembleFunction(s, ref param));
}
//用Lambda表达式将每个因子相乘
return(delegate(Tensor x)
{
Tensor ans = t * FactorsFun[0](x); for (int i = 1; i < FactorsFun.Count; i++)
{
ans *= FactorsFun[i](x);
}
return ans;
});
case 4: //当前要组装一个因子（一个函数，或者一个显示定义的向量、矩阵)这是最核心的部分。
int k = 0;
bool reved = false;
//处理前导*和/
while (true)
{
if (exp[k] == '/')
{
reved = !reved;
}
else if (exp[k] != '*')
{
break;
}
k++;
}
Functional.Function ret;
//去除前导*和/之后，可能就是立即数或变量，我们不希望在这里处理，所以再递归一次，交给case 5
if (k > 0)
{
ret = AssembleFunction(exp.Substring(k), ref param);
return(reved ? delegate(Tensor x) { return MathT.Inverse(ret(x)); } : ret);
}
if (exp[0] == '{')
{
int u = 0;
if (!Expression.GotoMatchedParen(ref exp, 0, ref u))
{
throw new Exception("在" + exp + "中括号不匹配");
}
if (u != exp.Length)
{
throw new Exception("在" + exp + "中，不符合语法");
}
return(AssembleFunction(exp.Substring(1, u - 2), ref param));
}
else if (exp[0] == '(')
{
s = exp.Substring(1, exp.Length - 2);
int cs = Expression.ClassOf(ref s);
if (2 <= cs && cs <= 6)
{
ret = AssembleFunction(s, ref param);
return(reved ? delegate(Tensor x) { return MathT.Inverse(ret(x)); } : ret);
}
}
else if (exp[0] == '[')
{
}
else
{
string fname = "";
List <string> paramexp = new List <string>();
if (Expression.SplitFunctuionFactor(ref exp, ref fname, ref paramexp))
{
if (StandardAssembler.ContainsKey(fname))
{
ret = StandardAssembler[fname](ref param, ref paramexp);
return(reved ? delegate(Tensor x) { return MathT.Inverse(ret(x)); } : ret);
}
}
}
break;
case 5: //组装一个立即数或者变量
if (Expression.IsArabic(exp[0]))
{
Tensor c = new Tensor(Convert.ToDouble(exp));
return(delegate(Tensor x)
{
return c;
});
}
else //一个变量（或一个常量）
{
if (ConstValue.ContainsKey(exp)) //先在常量表中找
{
Tensor c = new Tensor(ConstValue[exp]);
return
(delegate(Tensor x)
{
return c;
});
}
else //然后看是哪个参数表中的哪个变量
{
for (int i = 0; i < param.Count; i++)
{
if (exp == param[i])
{
return
(delegate(Tensor x)
{
return new Tensor(x.X[i]);
});
}
}
}
//在变量和常量中都没有找到，未定义的变量名，不可以组装函数
throw new Exception("组装函数错误：出现未定义的变量");
}
}
throw new Exception("未明确的错误，在组装 " + exp + " 时发生");
}
