/**
* <p>
* Performs a matrix multiplication on {@link DMatrixRBlock} submatrices.<br>
* <br>
* c = c - a * b <br>
* <br>
* </p>
*
* <p>
* It is assumed that all submatrices start at the beginning of a block and end at the end of a block.
* </p>
*
* @param blockLength Size of the blocks in the submatrix.
* @param A A submatrix. Not modified.
* @param B A submatrix. Not modified.
* @param C Result of the operation. Modified,
*/
public static void multMinus(int blockLength, DSubmatrixD1 A, DSubmatrixD1 B, DSubmatrixD1 C)
{
checkInput(blockLength, A, B, C);
for (int i = A.row0; i < A.row1; i += blockLength)
{
int heightA = Math.Min(blockLength, A.row1 - i);
for (int j = B.col0; j < B.col1; j += blockLength)
{
int widthB = Math.Min(blockLength, B.col1 - j);
int indexC = (i - A.row0 + C.row0) * C.original.numCols + (j - B.col0 + C.col0) * heightA;
for (int k = A.col0; k < A.col1; k += blockLength)
{
int widthA = Math.Min(blockLength, A.col1 - k);
int indexA = i * A.original.numCols + k * heightA;
int indexB = (k - A.col0 + B.row0) * B.original.numCols + j * widthA;
InnerMultiplication_DDRB.blockMultMinus(A.original.data, B.original.data, C.original.data,
indexA, indexB, indexC, heightA, widthA, widthB);
}
}
}
}
/**
* Inverts an upper or lower triangular block submatrix.
*
* @param blockLength
* @param upper Is it upper or lower triangular.
* @param T Triangular matrix that is to be inverted. Overwritten with solution. Modified.
* @param temp Work space variable that is size blockLength*blockLength.
*/
public static void invert(int blockLength,
bool upper,
DSubmatrixD1 T,
double[] temp)
{
if (upper)
{
throw new ArgumentException("Upper triangular matrices not supported yet");
}
if (temp.Length < blockLength * blockLength)
{
throw new ArgumentException("Temp must be at least blockLength*blockLength long.");
}
int M = T.row1 - T.row0;
double[] dataT = T.original.data;
int offsetT = T.row0 * T.original.numCols + M * T.col0;
for (int i = 0; i < M; i += blockLength)
{
int heightT = Math.Min(T.row1 - (i + T.row0), blockLength);
int indexII = offsetT + T.original.numCols * (i + T.row0) + heightT * (i + T.col0);
for (int j = 0; j < i; j += blockLength)
{
int widthX = Math.Min(T.col1 - (j + T.col0), blockLength);
for (int w = 0; w < temp.Length; w++)
{
temp[w] = 0;
}
for (int k = j; k < i; k += blockLength)
{
int widthT = Math.Min(T.col1 - (k + T.col0), blockLength);
int indL = offsetT + T.original.numCols * (i + T.row0) + heightT * (k + T.col0);
int indX = offsetT + T.original.numCols * (k + T.row0) + widthT * (j + T.col0);
InnerMultiplication_DDRB.blockMultMinus(dataT, dataT, temp, indL, indX, 0, heightT, widthT, widthX);
}
int indexX = offsetT + T.original.numCols * (i + T.row0) + heightT * (j + T.col0);
InnerTriangularSolver_DDRB.solveL(dataT, temp, heightT, widthX, heightT, indexII, 0);
Array.Copy(temp, 0, dataT, indexX, widthX * heightT);
}
InnerTriangularSolver_DDRB.invertLower(dataT, heightT, indexII);
}
}