public static Vector Fit(Matrix input, Vector y)
{
if (input == null || y == null)
{
throw new ArgumentNullException("输入不能为空");
}
if (input.RowCount != y.Count)
{
throw new ArgumentException("输入的长度不一致");
}
//tol = 10*eps*norm(C,1)*length(C);
// norm(C,1) = sum(abs(C))
var norm = new DenseVector(input.ColumnCount);
for (int i = 0; i < input.RowCount; i++)
{
for (int j = 0; j < input.ColumnCount; j++)
{
norm[j] += Math.Abs(input[i, j]);
}
}
var tol = 10 * Single.Epsilon * norm.Sum() * input.RowCount;
var P = new DenseVector(input.ColumnCount);
var Z = new DenseVector(input.ColumnCount);
for (int i = 1; i <= Z.Count; i++)
{
Z[i - 1] = i;
}
var ra = P.Clone();
var ZZ = Z.Clone();
var resid = y - input * ra;
var w = input.Transpose() * resid;
// set up iteration criterion
var outeriter = 0;
var iter = 0;
var itmax = 3 * input.ColumnCount;
var exitflag = 1;
while (Z.Any())
{
var widx = ((Vector)w).Slice((Vector)ZZ.Subtract(1));
bool brk = true;
foreach (var www in widx)
{
if ((www - tol) > 0)
{
brk = false;
break;
}
}
if (brk)
{
break;
}
if (!widx.Any())
{
break;
}
outeriter++;
var wt = widx.Maximum();
var t = widx.MaximumIndex();
t = (int)ZZ[t];
P[t - 1] = t;
Z[t - 1] = 0;
var PP = P.Find();
ZZ = Z.Find().Add(1);
var nzz = ZZ.Count;
var CP = new DenseMatrix(input.RowCount, input.ColumnCount);
for (int j = 0; j < input.RowCount; j++)
{
foreach (var pj in PP)
{
CP[j, (int)pj] = input[j, (int)pj];
}
foreach (var zj in ZZ)
{
CP[j, (int)zj - 1] = 0;
}
}
var z = CP.PseudoInverse() * y;
foreach (var zj in ZZ)
{
z[(int)zj - 1] = 0;
}
while (true)
{
var ztemp = ((Vector)z).Slice((Vector)PP);
brk = true;
foreach (var ztempp in ztemp)
{
if (ztempp <= tol)
{
brk = false;
break;
}
}
if (brk)
{
break;
}
iter = iter + 1;
if (iter > itmax)
{
exitflag = 0;
ra = z;
break;
}
var lst = new List <int>();
for (int i = 0; i < z.Count; i++)
{
if (z[i] <= tol && P[i] != 0)
{
lst.Add(i);
}
}
var QQ = lst.ToArray();
var ratemp = ((Vector)ra).Slice(QQ);
var alpha = (ratemp.PointwiseDivide(ratemp - ((Vector)z).Slice(QQ))).Min();
ra = ra + alpha * (z - ra);
lst = new List <int>();
for (int i = 0; i < ra.Count; i++)
{
if (Math.Abs(ra[i]) < tol && P[i] != 0)
{
lst.Add(i);
}
}
foreach (var i in lst)
{
Z[i] = i;
P[i] = 0;
}
PP = P.Find();
ZZ = Z.Find().Add(1);
nzz = ZZ.Count;
for (int j = 0; j < input.RowCount; j++)
{
foreach (var pj in PP)
{
CP[j, (int)pj] = input[j, (int)pj];
}
foreach (var zj in ZZ)
{
CP[j, (int)zj - 1] = 0;
}
}
z = CP.PseudoInverse() * y;
foreach (var zj in ZZ)
{
z[(int)zj - 1] = 0;
}
}
ra = z;
resid = y - input * ra;
w = input.Transpose() * resid;
}
return((Vector)ra);
}