public _nMatrix ReturnInverseOfUpperTriangularMatrix(_nMatrix UpperTriangularMatrix)
{
var dimN = UpperTriangularMatrix.n;
var D = ReturnDiagonalInverseMatrix(UpperTriangularMatrix);
var copy = CreateCopy(UpperTriangularMatrix);
copy.ReplaceDiagonalEntriesWithZero(copy);
copy = D.MultiplyByAnotherMatrix(copy);
var identityClass = new nIdentityMatrix();
var identity = identityClass.ReturnNIdentityMatrix(dimN);
var temp = copy.MultiplyByScalar(-1);
for (int i = 2; i < dimN; i++)
{
AddNextPowerTermToMatrixSeries(copy, ref temp, i);
}
var inverse = identity.AddAnotherMatrix(temp);
var copyPlus1 = identity.AddAnotherMatrix(copy);
var Test = inverse.MultiplyByAnotherMatrix(copyPlus1);
//var realTest = D.ReturnDiagonalInverseMatrix(D).MultiplyByAnotherMatrix(D).MultiplyByAnotherMatrix(Test);
return(inverse);
}
public _nMatrix ReturnDiagonalInverseMatrix(_nMatrix matrix)
{
int dim = matrix.n;
var identityMatrixClass = new nIdentityMatrix();
var inverseMatrix = identityMatrixClass.ReturnNIdentityMatrix(dim);
for (int i = 0; i < dim; i++)
{
inverseMatrix.SetValueAt(i + 1, i + 1, (1 / matrix.rows[i].vector[i]));
}
return(inverseMatrix);
}