/**
* <p>
* Adjusts the values of the Q and R matrices to take in account the effects of inserting
* a row to the 'A' matrix at the specified location. This operation requires about 6mn + O(n) flops.
* </p>
*
* <p>
* If Q and/or R does not have enough data elements to grow then an exception is thrown.
* </p>
*
* <p>
* The adjustment done is by computing a series of planar Givens rotations that make the adjusted R
* matrix upper triangular again. This is then used to modify the Q matrix.
* </p>
*
* @param Q The Q matrix which is to be modified, must be big enough to grow. Must be n by n.. Is modified.
* @param R The R matrix which is to be modified, must be big enough to grow. Must be m by n. Is modified.
* @param row The row being inserted. Not modified.
* @param rowIndex Which row index it is to be inserted at.
* @param resizeR Should the number of rows in R be changed? The additional rows are all zero.
*/
public void addRow(FMatrixRMaj Q, FMatrixRMaj R, float[] row, int rowIndex, bool resizeR)
{
// memory management and check precoditions
setQR(Q, R, 1);
m_m = m + 1;
if (Q.data.Length < m_m * m_m)
{
throw new ArgumentException("Q matrix does not have enough data to grow");
}
if (resizeR && R.data.Length < m_m * n)
{
throw new ArgumentException("R matrix does not have enough data to grow");
}
if (resizeR)
{
R.reshape(m_m, n, false);
}
U_tran.reshape(m_m, m_m, false);
// apply givens rotation to the first two rows of the augmented R matrix
applyFirstGivens(row);
applyLaterGivens();
// compute new Q matrix
updateInsertQ(rowIndex);
// discard the reference since it is no longer needed
this.Q = this.R = null;
}
public override void solve(FMatrixRMaj B, FMatrixRMaj X)
{
if (X.numRows != numCols)
{
throw new ArgumentException("Unexpected dimensions for X");
}
else if (B.numRows != numRows || B.numCols != X.numCols)
{
throw new ArgumentException("Unexpected dimensions for B");
}
int BnumCols = B.numCols;
// get the pivots and transpose them
int[] pivots = decomposition.getColPivots();
// solve each column one by one
for (int colB = 0; colB < BnumCols; colB++)
{
x_basic.reshape(numRows, 1);
Y.reshape(numRows, 1);
// make a copy of this column in the vector
for (int i = 0; i < numRows; i++)
{
Y.data[i] = B.get(i, colB);
}
// Solve Q*a=b => a = Q'*b
CommonOps_FDRM.multTransA(Q, Y, x_basic);
// solve for Rx = b using the standard upper triangular solver
TriangularSolver_FDRM.solveU(R11.data, x_basic.data, rank);
// finish the basic solution by filling in zeros
x_basic.reshape(numCols, 1, true);
for (int i = rank; i < numCols; i++)
{
x_basic.data[i] = 0;
}
if (norm2Solution && rank < numCols)
{
upgradeSolution(x_basic);
}
// save the results
for (int i = 0; i < numCols; i++)
{
X.set(pivots[i], colB, x_basic.data[i]);
}
}
}
public override bool setA(FMatrixRMaj A)
{
_setA(A);
if (!decomposition.decompose(A))
{
return(false);
}
rank = decomposition.getRank();
R.reshape(numRows, numCols);
decomposition.getR(R, false);
// extract the r11 triangle sub matrix
R11.reshape(rank, rank);
CommonOps_FDRM.extract(R, 0, rank, 0, rank, R11, 0, 0);
if (norm2Solution && rank < numCols)
{
// extract the R12 sub-matrix
W.reshape(rank, numCols - rank);
CommonOps_FDRM.extract(R, 0, rank, rank, numCols, W, 0, 0);
// W=inv(R11)*R12
TriangularSolver_FDRM.solveU(R11.data, 0, R11.numCols, R11.numCols, W.data, 0, W.numCols, W.numCols);
// set the identity matrix in the upper portion
W.reshape(numCols, W.numCols, true);
for (int i = 0; i < numCols - rank; i++)
{
for (int j = 0; j < numCols - rank; j++)
{
if (i == j)
{
W.set(i + rank, j, -1);
}
else
{
W.set(i + rank, j, 0);
}
}
}
}
return(true);
}
/**
* Performs QR decomposition on A
*
* @param A not modified.
*/
public override bool setA(FMatrixRMaj A)
{
if (A.numRows < A.numCols)
{
throw new ArgumentException("Can't solve for wide systems. More variables than equations.");
}
if (A.numRows > maxRows || A.numCols > maxCols)
{
setMaxSize(A.numRows, A.numCols);
}
R.reshape(A.numCols, A.numCols);
a.reshape(A.numRows, 1);
temp.reshape(A.numRows, 1);
_setA(A);
if (!decomposer.decompose(A))
{
return(false);
}
gammas = decomposer.getGammas();
QR = decomposer.getQR();
decomposer.getR(R, true);
return(true);
}
private void solveEigenvectorDuplicateEigenvalue(float real, int first, bool isTriangle)
{
float scale = Math.Abs(real);
if (scale == 0)
{
scale = 1;
}
eigenvectorTemp.reshape(N, 1, false);
eigenvectorTemp.zero();
if (first > 0)
{
if (isTriangle)
{
solveUsingTriangle(real, first, eigenvectorTemp);
}
else
{
solveWithLU(real, first, eigenvectorTemp);
}
}
eigenvectorTemp.reshape(N, 1, false);
for (int i = first; i < N; i++)
{
Complex_F32 c = _implicit.eigenvalues[N - i - 1];
if (c.isReal() && Math.Abs(c.real - real) / scale < 100.0f * UtilEjml.F_EPS)
{
eigenvectorTemp.data[i] = 1;
FMatrixRMaj v = new FMatrixRMaj(N, 1);
CommonOps_FDRM.multTransA(Q, eigenvectorTemp, v);
eigenvectors[N - i - 1] = v;
NormOps_FDRM.normalizeF(v);
eigenvectorTemp.data[i] = 0;
}
}
}
/**
* Compute the A matrix from the Q and R matrices.
*
* @return The A matrix.
*/
public override FMatrixRMaj getA()
{
if (A.data.Length < numRows * numCols)
{
A = new FMatrixRMaj(numRows, numCols);
}
A.reshape(numRows, numCols, false);
CommonOps_FDRM.mult(Q, R, A);
return(A);
}
public override void invert(FMatrixRMaj A_inv)
{
if (A_inv.numCols != numRows || A_inv.numRows != numCols)
{
throw new ArgumentException("Unexpected dimensions for A_inv");
}
I.reshape(numRows, numRows);
CommonOps_FDRM.setIdentity(I);
solve(I, A_inv);
}
public override bool setA(FMatrixRMaj A)
{
if (!base.setA(A))
{
return(false);
}
Q.reshape(A.numRows, A.numRows);
decomposition.getQ(Q, false);
return(true);
}
/**
* Updates the Q matrix to take in account the inserted matrix.
*
* @param rowIndex where the matrix has been inserted.
*/
private void updateInsertQ(int rowIndex)
{
Qm.set(Q);
Q.reshape(m_m, m_m, false);
for (int i = 0; i < rowIndex; i++)
{
for (int j = 0; j < m_m; j++)
{
float sum = 0;
for (int k = 0; k < m; k++)
{
sum += Qm.data[i * m + k] * U_tran.data[j * m_m + k + 1];
}
Q.data[i * m_m + j] = sum;
}
}
for (int j = 0; j < m_m; j++)
{
Q.data[rowIndex * m_m + j] = U_tran.data[j * m_m];
}
for (int i = rowIndex + 1; i < m_m; i++)
{
for (int j = 0; j < m_m; j++)
{
float sum = 0;
for (int k = 0; k < m; k++)
{
sum += Qm.data[(i - 1) * m + k] * U_tran.data[j * m_m + k + 1];
}
Q.data[i * m_m + j] = sum;
}
}
}
public override /**/ double quality()
{
return(SpecializedOps_FDRM.qualityTriangular(R));
}
/**
* <p>
* Upgrades the basic solution to the optimal 2-norm solution.
* </p>
*
* <pre>
* First solves for 'z'
*
* || x_b - P*[ R_11^-1 * R_12 ] * z ||2
* min z || [ - I_{n-r} ] ||
*
* </pre>
*
* @param X basic solution, also output solution
*/
protected void upgradeSolution(FMatrixRMaj X)
{
FMatrixRMaj z = Y; // recycle Y
// compute the z which will minimize the 2-norm of X
// because of the identity matrix tacked onto the end 'A' should never be singular
if (!internalSolver.setA(W))
{
throw new InvalidOperationException("This should never happen. Is input NaN?");
}
z.reshape(numCols - rank, 1);
internalSolver.solve(X, z);
// compute X by tweaking the original
CommonOps_FDRM.multAdd(-1, W, z, X);
}
private void init(FMatrixRBlock orig)
{
this.A = orig;
int height = Math.Min(A.blockLength, A.numRows);
V.reshape(height, A.numCols, A.blockLength, false);
tmp.reshape(height, A.numCols, A.blockLength, false);
if (gammas.Length < A.numCols)
{
gammas = new float[A.numCols];
}
zerosM.reshape(A.blockLength, A.blockLength + 1, false);
}
/**
* Performs QR decomposition on A
*
* @param A not modified.
*/
public override bool setA(FMatrixRMaj A)
{
if (A.numRows > maxRows || A.numCols > maxCols)
{
setMaxSize(A.numRows, A.numCols);
}
_setA(A);
if (!decomposer.decompose(A))
{
return(false);
}
Q.reshape(numRows, numRows, false);
R.reshape(numRows, numCols, false);
decomposer.getQ(Q, false);
decomposer.getR(R, false);
return(true);
}
public override /**/ double quality()
{
return(SpecializedOps_FDRM.qualityTriangular(R));
}
/**
* Solves for X using the QR decomposition.
*
* @param B A matrix that is n by m. Not modified.
* @param X An n by m matrix where the solution is written to. Modified.
*/
public override void solve(FMatrixRMaj B, FMatrixRMaj X)
{
if (X.numRows != numCols)
{
throw new ArgumentException("Unexpected dimensions for X");
}
else if (B.numRows != numRows || B.numCols != X.numCols)
{
throw new ArgumentException("Unexpected dimensions for B");
}
int BnumCols = B.numCols;
Y.reshape(numRows, 1, false);
Z.reshape(numRows, 1, false);
// solve each column one by one
for (int colB = 0; colB < BnumCols; colB++)
{
// make a copy of this column in the vector
for (int i = 0; i < numRows; i++)
{
Y.data[i] = B.get(i, colB);
}
// Solve Qa=b
// a = Q'b
CommonOps_FDRM.multTransA(Q, Y, Z);
// solve for Rx = b using the standard upper triangular solver
TriangularSolver_FDRM.solveU(R.data, Z.data, numCols);
// save the results
for (int i = 0; i < numCols; i++)
{
X.set(i, colB, Z.data[i]);
}
}
}
private void solveWithLU(float real, int index, FMatrixRMaj r)
{
FMatrixRMaj A = new FMatrixRMaj(index, index);
CommonOps_FDRM.extract(_implicit.A, 0, index, 0, index, A, 0, 0);
for (int i = 0; i < index; i++)
{
A.add(i, i, -real);
}
r.reshape(index, 1, false);
SpecializedOps_FDRM.subvector(_implicit.A, 0, index, index, false, 0, r);
CommonOps_FDRM.changeSign(r);
// TODO this must be very inefficient
if (!solver.setA(A))
{
throw new InvalidOperationException("Solve failed");
}
solver.solve(r, r);
}
/**
* If needed declares and sets up internal data structures.
*
* @param A Matrix being decomposed.
*/
public void init(FMatrixRMaj A)
{
if (A.numRows != A.numCols)
{
throw new ArgumentException("Must be square");
}
if (A.numCols != N)
{
N = A.numCols;
QT.reshape(N, N, false);
if (w.Length < N)
{
w = new float[N];
gammas = new float[N];
b = new float[N];
}
}
// just copy the top right triangle
QT.set(A);
}
/**
* <p>
* Adjusts the values of the Q and R matrices to take in account the effects of removing
* a row from the 'A' matrix at the specified location. This operation requires about 6mn + O(n) flops.
* </p>
*
* <p>
* The adjustment is done by computing a series of planar Givens rotations that make the removed row in Q
* equal to [1 0 ... 0].
* </p>
*
* @param Q The Q matrix. Is modified.
* @param R The R matrix. Is modified.
* @param rowIndex Which index of the row that is being removed.
* @param resizeR should the shape of R be adjusted?
*/
public void deleteRow(FMatrixRMaj Q, FMatrixRMaj R, int rowIndex, bool resizeR)
{
setQR(Q, R, 0);
if (m - 1 < n)
{
throw new ArgumentException("Removing any row would make the system under determined.");
}
m_m = m - 1;
U_tran.reshape(m, m, false);
if (resizeR)
{
R.reshape(m_m, n, false);
}
computeRemoveGivens(rowIndex);
updateRemoveQ(rowIndex);
updateRemoveR();
// discard the reference since it is no longer needed
this.Q = this.R = null;
}
/**
* <p>
* Performs Choleksy decomposition on the provided matrix.
* </p>
*
* <p>
* If the matrix is not positive definite then this function will return
* false since it can't complete its computations. Not all errors will be
* found.
* </p>
* @return True if it was able to finish the decomposition.
*/
protected override bool decomposeLower()
{
if (n < blockWidth)
{
B.reshape(0, 0, false);
}
else
{
B.reshape(blockWidth, n - blockWidth, false);
}
int numBlocks = n / blockWidth;
int remainder = n % blockWidth;
if (remainder > 0)
{
numBlocks++;
}
B.numCols = n;
for (int i = 0; i < numBlocks; i++)
{
B.numCols -= blockWidth;
if (B.numCols > 0)
{
// apply cholesky to the current block
if (!chol.decompose(T, (i * blockWidth) * T.numCols + i * blockWidth, blockWidth))
{
return(false);
}
int indexSrc = i * blockWidth * T.numCols + (i + 1) * blockWidth;
int indexDst = (i + 1) * blockWidth * T.numCols + i * blockWidth;
// B = L^(-1) * B
solveL_special(chol.getL().data, T, indexSrc, indexDst, B);
int indexL = (i + 1) * blockWidth * n + (i + 1) * blockWidth;
// c = c - a^T*a
symmRankTranA_sub(B, T, indexL);
}
else
{
int width = remainder > 0 ? remainder : blockWidth;
if (!chol.decompose(T, (i * blockWidth) * T.numCols + i * blockWidth, width))
{
return(false);
}
}
}
// zero the top right corner.
for (int i = 0; i < n; i++)
{
for (int j = i + 1; j < n; j++)
{
t[i * n + j] = 0.0f;
}
}
return(true);
}
public override void solve(FMatrixRMaj B, FMatrixRMaj X)
{
if (X.numRows != numCols)
{
throw new ArgumentException("Unexpected dimensions for X");
}
else if (B.numRows != numRows || B.numCols != X.numCols)
{
throw new ArgumentException("Unexpected dimensions for B");
}
int BnumCols = B.numCols;
// get the pivots and transpose them
int[] pivots = decomposition.getColPivots();
float[][] qr = decomposition.getQR();
float[] gammas = decomposition.getGammas();
// solve each column one by one
for (int colB = 0; colB < BnumCols; colB++)
{
x_basic.reshape(numRows, 1);
Y.reshape(numRows, 1);
// make a copy of this column in the vector
for (int i = 0; i < numRows; i++)
{
x_basic.data[i] = B.get(i, colB);
}
// Solve Q*x=b => x = Q'*b
// Q_n*b = (I-gamma*u*u^T)*b = b - u*(gamma*U^T*b)
for (int i = 0; i < rank; i++)
{
float[] u = qr[i];
float vv = u[i];
u[i] = 1;
QrHelperFunctions_FDRM.rank1UpdateMultR(x_basic, u, gammas[i], 0, i, numRows, Y.data);
u[i] = vv;
}
// solve for Rx = b using the standard upper triangular solver
TriangularSolver_FDRM.solveU(R11.data, x_basic.data, rank);
// finish the basic solution by filling in zeros
x_basic.reshape(numCols, 1, true);
for (int i = rank; i < numCols; i++)
{
x_basic.data[i] = 0;
}
if (norm2Solution && rank < numCols)
{
upgradeSolution(x_basic);
}
// save the results
for (int i = 0; i < numCols; i++)
{
X.set(pivots[i], colB, x_basic.data[i]);
}
}
}