/**
* <p>
* Returns the value of the element in the vector that has the minimum value.<br>
* <br>
* Min{ a<sub>i</sub> } for all<br>
* </p>
*
* @param a A matrix. Not modified.
* @return The value of element in the vector with the minimum value.
*/
public static double elementMin(DMatrix2 a)
{
double min = a.a1;
if (a.a2 < min)
{
min = a.a2;
}
return(min);
}
/**
* <p>
* Returns the value of the element in the vector that has the largest value.<br>
* <br>
* Max{ a<sub>i</sub> } for all i<br>
* </p>
*
* @param a A vector. Not modified.
* @return The max element value of the matrix.
*/
public static double elementMax(DMatrix2 a)
{
double max = a.a1;
if (a.a2 > max)
{
max = a.a2;
}
return(max);
}
public static bool isIdentical(DMatrix2 a, DMatrix2 b, double tol)
{
if (!MatrixFeatures_DDRM.isIdentical(a.a1, b.a1, tol))
{
return(false);
}
if (!MatrixFeatures_DDRM.isIdentical(a.a2, b.a2, tol))
{
return(false);
}
return(true);
}
public static bool hasUncountable(DMatrix2 a)
{
if (UtilEjml.isUncountable(a.a1))
{
return(true);
}
if (UtilEjml.isUncountable(a.a2))
{
return(true);
}
return(false);
}
public static double normF(DMatrix2 M)
{
double scale = CommonOps_DDF2.elementMaxAbs(M);
if (scale == 0.0)
{
return(0.0);
}
double a1 = M.a1 / scale, a2 = M.a2 / scale;
double sum = a1 * a1 + a2 * a2;
return(scale * Math.Sqrt(sum));
}
/**
* <p>
* Returns the absolute value of the element in the vector that has the smallest absolute value.<br>
* <br>
* Min{ |a<sub>i</sub>| } for all i<br>
* </p>
*
* @param a A matrix. Not modified.
* @return The max element value of the vector.
*/
public static double elementMinAbs(DMatrix2 a)
{
double min = Math.Abs(a.a1);
double tmp = Math.Abs(a.a1);
if (tmp < min)
{
min = tmp;
}
tmp = Math.Abs(a.a2);
if (tmp < min)
{
min = tmp;
}
return(min);
}
/**
* <p>
* Returns the absolute value of the element in the vector that has the largest absolute value.<br>
* <br>
* Max{ |a<sub>i</sub>| } for all i<br>
* </p>
*
* @param a A matrix. Not modified.
* @return The max abs element value of the vector.
*/
public static double elementMaxAbs(DMatrix2 a)
{
double max = Math.Abs(a.a1);
double tmp = Math.Abs(a.a2);
if (tmp > max)
{
max = tmp;
}
tmp = Math.Abs(a.a2);
if (tmp > max)
{
max = tmp;
}
return(max);
}
/**
* Extracts the column from the matrix a.
* @param a Input matrix
* @param column Which column is to be extracted
* @param output output. Storage for the extracted column. If null then a new vector will be returned.
* @return The extracted column.
*/
public static DMatrix2 extractColumn(DMatrix2x2 a, int column, DMatrix2 output)
{
if (output == null)
{
output = new DMatrix2();
}
switch (column)
{
case 0:
output.a1 = a.a11;
output.a2 = a.a21;
break;
case 1:
output.a1 = a.a12;
output.a2 = a.a22;
break;
default:
throw new ArgumentException("Out of bounds column. column = " + column);
}
return(output);
}
/**
* Extracts the row from the matrix a.
* @param a Input matrix
* @param row Which row is to be extracted
* @param output output. Storage for the extracted row. If null then a new vector will be returned.
* @return The extracted row.
*/
public static DMatrix2 extractRow(DMatrix2x2 a, int row, DMatrix2 output)
{
if (output == null)
{
output = new DMatrix2();
}
switch (row)
{
case 0:
output.a1 = a.a11;
output.a2 = a.a12;
break;
case 1:
output.a1 = a.a21;
output.a2 = a.a22;
break;
default:
throw new ArgumentException("Out of bounds row. row = " + row);
}
return(output);
}
/**
* Converts {@link DMatrix2} into {@link DMatrixRMaj}.
*
* @param input Input matrix.
* @param output Output matrix. If null a new matrix will be declared.
* @return Converted matrix.
*/
public static DMatrixRMaj convert(DMatrix2 input, DMatrixRMaj output)
{
if (output == null)
{
output = new DMatrixRMaj(2, 1);
}
if (output.NumRows != 1 && output.NumCols != 1)
{
throw new ArgumentException("One row or column must have a length of 1 for it to be a vector");
}
int length = Math.Max(output.NumRows, output.NumCols);
if (length != 2)
{
throw new ArgumentException("Length of input vector is not 2. It is " + length);
}
output.data[0] = input.a1;
output.data[1] = input.a2;
return(output);
}
/**
* Converts {@link DMatrixRMaj} into {@link DMatrix2}
*
* @param input Input matrix.
* @param output Output matrix. If null a new matrix will be declared.
* @return Converted matrix.
*/
public static DMatrix2 convert(DMatrixRMaj input, DMatrix2 output)
{
if (output == null)
{
output = new DMatrix2();
}
if (input.getNumRows() != 1 && input.getNumCols() != 1)
{
throw new ArgumentException("One row or column must have a length of 1 for it to be a vector");
}
int length = Math.Max(input.getNumRows(), input.getNumCols());
if (length != 2)
{
throw new ArgumentException("Length of input vector is not 2. It is " + length);
}
output.a1 = input.data[0];
output.a2 = input.data[1];
return(output);
}
/**
* <p>
* Performs an in-place element by element scalar multiplication.<br>
* <br>
* a<sub>ij</sub> = α*a<sub>ij</sub>
* </p>
*
* @param a The vector that is to be scaled. Modified.
* @param alpha the amount each element is multiplied by.
*/
public static void scale(double alpha, DMatrix2 a)
{
a.a1 *= alpha;
a.a2 *= alpha;
}
/**
* <p>
* Performs an element by element scalar multiplication.<br>
* <br>
* b<sub>i</sub> = α*a<sub>i</sub>
* </p>
*
* @param alpha the amount each element is multiplied by.
* @param a The vector that is to be scaled. Not modified.
* @param b Where the scaled matrix is stored. Modified.
*/
public static void scale(double alpha, DMatrix2 a, DMatrix2 b)
{
b.a1 = a.a1 * alpha;
b.a2 = a.a2 * alpha;
}
/**
* <p>Performs an element by element division operation:<br>
* <br>
* c<sub>i</sub> = a<sub>i</sub> / b<sub>i</sub> <br>
* </p>
* @param a The left vector in the division operation. Not modified.
* @param b The right vector in the division operation. Not modified.
* @param c Where the results of the operation are stored. Modified.
*/
public static void elementDiv(DMatrix2 a, DMatrix2 b, DMatrix2 c)
{
c.a1 = a.a1 / b.a1;
c.a2 = a.a2 / b.a2;
}
/**
* <p>Performs the following operation:<br>
* <br>
* a = a + b <br>
* a<sub>i</sub> = a<sub>i</sub> + b<sub>i</sub> <br>
* </p>
*
* @param a A Vector. Modified.
* @param b A Vector. Not modified.
*/
public static void addEquals(DMatrix2 a, DMatrix2 b)
{
a.a1 += b.a1;
a.a2 += b.a2;
}
/**
* <p>Performs the vector dot product:<br>
* <br>
* c = a * b <br>
* <br>
* c ≥ ∑<sub>k=1:n</sub> { b<sub>k</sub> * a<sub>k</sub> }
* </p>
*
* @param a The left vector in the multiplication operation. Not modified.
* @param b The right matrix in the multiplication operation. Not modified.
* @return The dot product
*/
public static double dot(DMatrix2 a, DMatrix2 b)
{
return(a.a1 * b.a1 + a.a2 * b.a2);
}
/**
* <p>Performs an element by element division operation:<br>
* <br>
* a<sub>i</sub> = a<sub>i</sub> / b<sub>i</sub> <br>
* </p>
* @param a The left vector in the division operation. Modified.
* @param b The right vector in the division operation. Not modified.
*/
public static void elementDiv(DMatrix2 a, DMatrix2 b)
{
a.a1 /= b.a1;
a.a2 /= b.a2;
}
/**
* <p>
* Sets every element in the vector to the specified value.<br>
* <br>
* a<sub>i</sub> = value
* <p>
*
* @param a A vector whose elements are about to be set. Modified.
* @param v The value each element will have.
*/
public static void fill(DMatrix2 a, double v)
{
a.a1 = v;
a.a2 = v;
}
/**
* <p>
* Performs an element by element scalar division. Scalar denominator.<br>
* <br>
* b<sub>i</sub> = a<sub>i</sub> /α
* </p>
*
* @param alpha the amount each element is divided by.
* @param a The vector whose elements are to be divided. Not modified.
* @param b Where the results are stored. Modified.
*/
public static void divide(DMatrix2 a, double alpha, DMatrix2 b)
{
b.a1 = a.a1 / alpha;
b.a2 = a.a2 / alpha;
}
/**
* <p>Performs the following operation:<br>
* <br>
* a = a - b <br>
* a<sub>i</sub> = a<sub>i</sub> - b<sub>i</sub> <br>
* </p>
*
* @param a A Vector. Modified.
* @param b A Vector. Not modified.
*/
public static void subtractEquals(DMatrix2 a, DMatrix2 b)
{
a.a1 -= b.a1;
a.a2 -= b.a2;
}
/**
* <p>Performs the following operation:<br>
* <br>
* c = a - b <br>
* c<sub>i</sub> = a<sub>i</sub> - b<sub>i</sub> <br>
* </p>
*
* <p>
* Vector C can be the same instance as Vector A and/or B.
* </p>
*
* @param a A Vector. Not modified.
* @param b A Vector. Not modified.
* @param c A Vector where the results are stored. Modified.
*/
public static void subtract(DMatrix2 a, DMatrix2 b, DMatrix2 c)
{
c.a1 = a.a1 - b.a1;
c.a2 = a.a2 - b.a2;
}
public static double fastNormF(DMatrix2 M)
{
double sum = M.a1 * M.a1 + M.a2 * M.a2;
return(Math.Sqrt(sum));
}
/**
* <p>Performs the following operation:<br>
* <br>
* c = a + b <br>
* c<sub>i</sub> = a<sub>i</sub> + b<sub>i</sub> <br>
* </p>
*
* <p>
* Vector C can be the same instance as Vector A and/or B.
* </p>
*
* @param a A Vector. Not modified.
* @param b A Vector. Not modified.
* @param c A Vector where the results are stored. Modified.
*/
public static void add(DMatrix2 a, DMatrix2 b, DMatrix2 c)
{
c.a1 = a.a1 + b.a1;
c.a2 = a.a2 + b.a2;
}
/**
* <p>
* Extracts all diagonal elements from 'input' and places them inside the 'output' vector. Elements
* are in sequential order.
* </p>
*
*
* @param input Matrix. Not modified.
* @param output Vector containing diagonal elements. Modified.
*/
public static void diag(DMatrix2x2 input, DMatrix2 output)
{
output.a1 = input.a11;
output.a2 = input.a22;
}
/**
* <p>
* Performs an in-place element by element scalar division. Scalar denominator.<br>
* <br>
* a<sub>i</sub> = a<sub>i</sub>/α
* </p>
*
* @param a The vector whose elements are to be divided. Modified.
* @param alpha the amount each element is divided by.
*/
public static void divide(DMatrix2 a, double alpha)
{
a.a1 /= alpha;
a.a2 /= alpha;
}
/**
* <p>Performs an element by element multiplication operation:<br>
* <br>
* a<sub>i</sub> = a<sub>i</sub> * b<sub>i</sub> <br>
* </p>
* @param a The left vector in the multiplication operation. Modified.
* @param b The right vector in the multiplication operation. Not modified.
*/
public static void elementMult(DMatrix2 a, DMatrix2 b)
{
a.a1 *= b.a1;
a.a2 *= b.a2;
}
/**
* <p>
* Changes the sign of every element in the vector.<br>
* <br>
* a<sub>i</sub> = -a<sub>i</sub>
* </p>
*
* @param a A vector. Modified.
*/
public static void changeSign(DMatrix2 a)
{
a.a1 = -a.a1;
a.a2 = -a.a2;
}
/**
* <p>Performs an element by element multiplication operation:<br>
* <br>
* c<sub>i</sub> = a<sub>i</sub> * b<sub>j</sub> <br>
* </p>
* @param a The left vector in the multiplication operation. Not modified.
* @param b The right vector in the multiplication operation. Not modified.
* @param c Where the results of the operation are stored. Modified.
*/
public static void elementMult(DMatrix2 a, DMatrix2 b, DMatrix2 c)
{
c.a1 = a.a1 * b.a1;
c.a2 = a.a2 * b.a2;
}
public static void normalizeF(DMatrix2 M)
{
double val = normF(M);
CommonOps_DDF2.divide(M, val);
}
/**
* <p>Performs vector to matrix multiplication:<br>
* <br>
* c = a * b <br>
* <br>
* c<sub>j</sub> = ∑<sub>k=1:n</sub> { b<sub>k</sub> * a<sub>kj</sub> }
* </p>
*
* @param a The left vector in the multiplication operation. Not modified.
* @param b The right matrix in the multiplication operation. Not modified.
* @param c Where the results of the operation are stored. Modified.
*/
public static void mult(DMatrix2 a, DMatrix2x2 b, DMatrix2 c)
{
c.a1 = a.a1 * b.a11 + a.a2 * b.a21;
c.a2 = a.a1 * b.a12 + a.a2 * b.a22;
}
