| public GetColumn ( int passedColumnIndex ) : double[] | ||
| passedColumnIndex | int | |
| return | double[] | |
/// <summary>
/// Takes values from a matrix and determines a cofactor by removing a certain row and column from the matrix.
/// Logic developed with help from Andrew Morton on stackoverflow:
/// http://stackoverflow.com/questions/24416946/next-step-in-calculating-a-matrix-determinant
/// </summary>
public Matrix GetSubMatrix(int[] indicesOfRowsToKeep, int[] indicesOfColumnsToKeep)
{
Matrix subMatrix = new Matrix(indicesOfRowsToKeep.Length, indicesOfColumnsToKeep.Length);
Matrix tempMatrix = new Matrix(indicesOfRowsToKeep.Length, this.NumberOfColumns);
int insertRowAt = 0;
foreach (int rowToKeep in indicesOfRowsToKeep)
{
tempMatrix.SetRow(insertRowAt, this.GetRow(rowToKeep));
insertRowAt++;
}
int insertColumnAt = 0;
foreach (int columnToKeep in indicesOfColumnsToKeep)
{
subMatrix.SetColumn(insertColumnAt, tempMatrix.GetColumn(columnToKeep));
insertColumnAt++;
}
return subMatrix;
}
public void Matrix_GetColumnStandardTest()
{
Matrix testMatrix = new Matrix(3, 2);
double[] columnTwoOfTestMatrix = {7,8,9};
testMatrix.SetColumn(1, columnTwoOfTestMatrix);
testMatrix.GetColumn(1).ShouldBeEquivalentTo(columnTwoOfTestMatrix);
}
private static Point _pointFromProjectiveColumnVector(Matrix projectiveVector)
{
var col = projectiveVector.GetColumn(0);
//smallest we're allowing is 1 millionth
if (Math.Abs(col[3]) < 0.000001)
{
return Point.Origin;
}
else
{
var x = col[0]/col[3];
var y = col[1]/col[3];
var z = col[2]/col[3];
return Point.MakePointWithInches(x, y, z);
}
}