ColVector¶

class ColVector(*args, **kwargs)¶

Bases: ArrayDouble2D

Implementation of column vector and the associated operations.

This class provides a data structure for a column vector that contains values of double. It contains also some functions to achieve a set of operations on these vectors.

The vpColVector class is derived from vpArray2D<double> .

The code below shows how to create a 3-element column vector of doubles, set the element values and access them:

#include <visp3/code/vpColVector.h

#ifdef ENABLE_VISP_NAMESPACE
using namespace VISP_NAMESPACE_NAME;
#endif

int main()
{
  vpColVector v(3);
  v[0] = -1; v[1] = -2.1; v[2] = -3;

  std::cout << "v:" << std::endl;
  for (unsigned int i = 0; i < v.size(); ++i) {
    std::cout << v[i] << std::endl;
  }
}

Once build, this previous code produces the following output:

v:
-1
-2.1
-3

You can also use operator<< to initialize a column vector as previously:

#include <visp3/code/vpColVector.h

#ifdef ENABLE_VISP_NAMESPACE
using namespace VISP_NAMESPACE_NAME;
#endif

int main()
{
  vpColVector v;
  v << -1, -2.1, -3;
  std::cout << "v:" << v << std::endl;
}

If ViSP is build with c++11 enabled, you can do the same using:

#include <visp3/code/vpColVector.h

#ifdef ENABLE_VISP_NAMESPACE
using namespace VISP_NAMESPACE_NAME;
#endif

int main()
{
  vpColVector v({-1, -2.1, -3});
  std::cout << "v:\n" << v << std::endl;
}

The vector could also be initialized using operator=(const std::initializer_list< double > &)

#ifdef ENABLE_VISP_NAMESPACE
using namespace VISP_NAMESPACE_NAME;
#endif

int main()
{
  vpColVector v;
  v = {-1, -2.1, -3};
}

JSON serialization

Since ViSP 3.6.0, if ViSP is build with soft_tool_json 3rd-party we introduce JSON serialization capabilities for vpColVector . The following sample code shows how to save a pose vector in a file named col-vector.json and reload the values from this JSON file.

#include <visp3/core/vpColVector.h>

#ifdef ENABLE_VISP_NAMESPACE
using namespace VISP_NAMESPACE_NAME;
#endif

int main()
{
#if defined(VISP_HAVE_NLOHMANN_JSON)
  std::string filename = "col-vector.json";
  {
    vpColVector v({ 1, 2, 3, 4 });
    std::ofstream file(filename);
    const nlohmann::json j = v;
    file << j;
    file.close();
  }
  {
    std::ifstream file(filename);
    const nlohmann::json j = nlohmann::json::parse(file);
    vpColVector v;
    v = j.get<vpColVector>();
    file.close();
    std::cout << "Read homogeneous matrix from " << filename << ":\n" << v.t() << std::endl;
  }
#endif
}

If you build and execute the sample code, it will produce the following output:

Read homogeneous matrix from col-vector.json:
1  2  3  4

The content of the pose-vector.json file is the following:

$ cat col-vector.json
{"cols":1,"data":[1.0,2.0,3.0,4.0],"rows":4,"type":"vpColVector"}

Overloaded function.

__init__(self: visp._visp.core.ColVector) -> None

Basic constructor that creates an empty 0-size column vector.

__init__(self: visp._visp.core.ColVector, n: int) -> None
__init__(self: visp._visp.core.ColVector, n: int, val: float) -> None

Construct a column vector of size n. Each element is set to val .

__init__(self: visp._visp.core.ColVector, v: visp._visp.core.ColVector) -> None

Copy constructor that allows to construct a column vector from an other one.

__init__(self: visp._visp.core.ColVector, v: visp._visp.core.ColVector, r: int, nrows: int) -> None

Construct a column vector from a part of an input column vector v .

The sub-vector starting from v[r] element and ending on v[r+nrows-1] element is used to initialize the constructed column vector.

Note

See init()

Parameters:

v: Input column vector used for initialization.
r: row index in v that corresponds to the first element of the column vector to construct.
nrows: Number of rows of the constructed column vector.

__init__(self: visp._visp.core.ColVector, v: visp._visp.core.RotationVector) -> None
__init__(self: visp._visp.core.ColVector, p: visp._visp.core.PoseVector) -> None
__init__(self: visp._visp.core.ColVector, t: visp._visp.core.TranslationVector) -> None
__init__(self: visp._visp.core.ColVector, M: visp._visp.core.Matrix) -> None
__init__(self: visp._visp.core.ColVector, M: visp._visp.core.Matrix, j: int) -> None

Constructor that takes column j of matrix M .

__init__(self: visp._visp.core.ColVector, v: list[float]) -> None
__init__(self: visp._visp.core.ColVector, v: list[float]) -> None
__init__(self: visp._visp.core.ColVector, list: std::initializer_list<double>) -> None
__init__(self: visp._visp.core.ColVector, np_array: numpy.ndarray[numpy.float64]) -> None

Construct a column vector by copying a 1D numpy array.

Parameters:

np_array: The numpy 1D array to copy.

Methods

`__init__`	Overloaded function.
`clear`	Removes all elements from the vector (which are destroyed), leaving the container with a size of 0.
`cross`	Compute and return the cross product of two 3-dimension vectors: \(a \times b\) .
`crossProd`	Compute and return the cross product of two vectors \(a \times b\) .
`deg2rad`	Converts a column vector containing angles in degrees into radians and returns a reference to the vector.
`dotProd`	Compute end return the dot product of two column vectors:
`extract`	Extract a sub-column vector from a column vector.
`frobeniusNorm`	Compute and return the Frobenius norm \(\|\|v\|\| = \sqrt{ \sum_{v_{i}^2}}\) of all the elements \(v_{i}\) of the column vector \(\bf v\) that is of dimension \(m\) .
`hadamard`	Overloaded function.
`infinityNorm`	Compute and return the infinity norm \({\|\|v\|\|}_{\infty} = max\left({\mid v_{i} \mid}\right)\) with \(i \in \{0, ..., m-1\}\) where m is the vector size and \(v_i\) an element of the vector.
`init`	Initialize the column vector from a part of an input column vector v .
`insert`	Overloaded function.
`invSort`	Return a column vector with elements of v that are reverse sorted with values going from greatest to lowest.
`mean`	Compute the mean value of all the elements of the vector.
`median`	Compute the median value of all the elements of the vector.
`normalize`	Overloaded function.
`numpy`	Numpy view of the underlying array data.
`print`	Pretty print a column vector.
`rad2deg`	Note See deg2rad()
`reshape`	Overloaded function.
`resize`	Overloaded function.
`skew`	Compute the skew symmetric matrix \([{\bf v}]_\times\) of vector v.
`sort`	Return a column vector with elements of v that are sorted with values going from lowest to greatest.
`stack`	Overloaded function.
`stackVectors`	Overloaded function.
`stdev`	Compute the standard deviation value of all the elements of the vector.
`strCppCode`	Returns a C++ code representation of this data array (see cppPrint in the C++ documentation)
`strCsv`	Returns the CSV representation of this data array (see csvPrint in the C++ documentation)
`strMaple`	Returns the CSV representation of this data array (see maplePrint in the C++ documentation)
`strMatlab`	Returns the Matlab representation of this data array (see matlabPrint in the C++ documentation)
`sum`	Return the sum of all the elements \(v_{i}\) of the column vector \(\bf v\) that is of dimension \(m\) .
`sumSquare`	Return the sum of squares of all the elements \(v_{i}\) of the column vector \(\bf v\) that is of dimension \(m\) .
`t`	Overloaded function.
`toStdVector`	return: The corresponding std::vector<double>.
`transpose`	Overloaded function.
`view`	Construct a column vector that is a view of a numpy array.

Inherited Methods

`getMaxValue`
`getCols`	Return the number of columns of the 2D array.
`save`	Overloaded function.
`size`	Return the number of elements of the 2D array.
`conv2`	Overloaded function.
`getMinValue`
`saveYAML`
`getRows`	Return the number of rows of the 2D array.
`insertStatic`

Operators

`__add__`	Overloaded function.
`__doc__`
`__eq__`	Overloaded function.
`__getitem__`	Overloaded function.
`__hash__`
`__iadd__`	Operator that allows to add two column vectors.
`__imul__`	Operator that allows to multiply each element of a column vector by a scalar.
`__init__`	Overloaded function.
`__isub__`	Operator that allows to subtract two column vectors.
`__itruediv__`	Operator that allows to divide each element of a column vector by a scalar.
`__module__`
`__mul__`	Overloaded function.
`__ne__`	Overloaded function.
`__neg__`	Operator that allows to negate all the column vector elements.
`__setitem__`	Overloaded function.
`__sub__`	Operator subtraction of two vectors this = this - v
`__truediv__`	Operator that allows to divide each element of a column vector by a scalar.

Attributes

`__annotations__`
`__hash__`

__add__(*args, **kwargs)¶

Overloaded function.

__add__(self: visp._visp.core.ColVector, v: visp._visp.core.ColVector) -> visp._visp.core.ColVector

Operator that allows to add two column vectors.

__add__(self: visp._visp.core.ColVector, t: visp._visp.core.TranslationVector) -> visp._visp.core.TranslationVector

Operator that allows to add a column vector to a translation vector.

Parameters:

t: 3-dimension translation vector to add.

Returns:

The sum of the current column vector (*this) and the translation vector to add.

vpTranslationVector t1(1,2,3);
vpColVector v(3);
v[0] = 4;
v[1] = 5;
v[2] = 6;
vpTranslationVector t2;

t2 = v + t1;
// t1 and v leave unchanged
// t2 is now equal to : 5, 7, 9

__eq__(*args, **kwargs)¶

Overloaded function.

__eq__(self: visp._visp.core.ColVector, v: visp._visp.core.ColVector) -> bool

Compare two column vectors.

Parameters:

v: Vector to compare with.

Returns:

true when their respective size and their respective values are the same, false when their size or values differ.

__eq__(self: visp._visp.core.ColVector, v: float) -> bool

Compare a column vector to a floating point value.

Parameters:

v: Floating point value to compare with.

Returns:

true when all the values of the vector are equal to the floating point value v , false otherwise.

__getitem__(*args, **kwargs)¶

Overloaded function.

__getitem__(self: visp._visp.core.ColVector, arg0: int) -> float
__getitem__(self: visp._visp.core.ColVector, arg0: slice) -> numpy.ndarray[numpy.float64]

__iadd__(self, v: visp._visp.core.ColVector) → visp._visp.core.ColVector¶: Operator that allows to add two column vectors.

__imul__(self, x: float) → visp._visp.core.ColVector¶

Operator that allows to multiply each element of a column vector by a scalar.

vpColVector v(3);
v[0] = 1;
v[1] = 2;
v[2] = 3;

v *= 3;
// v is now equal to : [3, 6, 9]

Parameters:

x: float¶: The scalar.

Returns:

The column vector multiplied by the scalar.

__init__(*args, **kwargs)¶

Overloaded function.

__init__(self: visp._visp.core.ColVector) -> None

Basic constructor that creates an empty 0-size column vector.

__init__(self: visp._visp.core.ColVector, n: int) -> None
__init__(self: visp._visp.core.ColVector, n: int, val: float) -> None

Construct a column vector of size n. Each element is set to val .

__init__(self: visp._visp.core.ColVector, v: visp._visp.core.ColVector) -> None

Copy constructor that allows to construct a column vector from an other one.

__init__(self: visp._visp.core.ColVector, v: visp._visp.core.ColVector, r: int, nrows: int) -> None

Construct a column vector from a part of an input column vector v .

The sub-vector starting from v[r] element and ending on v[r+nrows-1] element is used to initialize the constructed column vector.

Note

See init()

Parameters:

v: Input column vector used for initialization.
r: row index in v that corresponds to the first element of the column vector to construct.
nrows: Number of rows of the constructed column vector.

__init__(self: visp._visp.core.ColVector, v: visp._visp.core.RotationVector) -> None
__init__(self: visp._visp.core.ColVector, p: visp._visp.core.PoseVector) -> None
__init__(self: visp._visp.core.ColVector, t: visp._visp.core.TranslationVector) -> None
__init__(self: visp._visp.core.ColVector, M: visp._visp.core.Matrix) -> None
__init__(self: visp._visp.core.ColVector, M: visp._visp.core.Matrix, j: int) -> None

Constructor that takes column j of matrix M .

__init__(self: visp._visp.core.ColVector, v: list[float]) -> None
__init__(self: visp._visp.core.ColVector, v: list[float]) -> None
__init__(self: visp._visp.core.ColVector, list: std::initializer_list<double>) -> None
__init__(self: visp._visp.core.ColVector, np_array: numpy.ndarray[numpy.float64]) -> None

Construct a column vector by copying a 1D numpy array.

Parameters:

np_array: The numpy 1D array to copy.

__isub__(self, v: visp._visp.core.ColVector) → visp._visp.core.ColVector¶: Operator that allows to subtract two column vectors.

__itruediv__(self, x: float) → visp._visp.core.ColVector¶

Operator that allows to divide each element of a column vector by a scalar.

vpColVector v(3);
v[0] = 8;
v[1] = 4;
v[2] = 2;

v /= 2;
// v is now equal to : [4, 2, 1]

Parameters:

x: float¶: The scalar.

Returns:

The column vector divided by the scalar.

__mul__(*args, **kwargs)¶

Overloaded function.

__mul__(self: visp._visp.core.ColVector, v: visp._visp.core.ColVector) -> float

Operator that performs the dot product between two column vectors.

Note

See dotProd()

__mul__(self: visp._visp.core.ColVector, v: visp._visp.core.RowVector) -> visp._visp.core.Matrix

Multiply a column vector by a row vector.

Parameters:

v: Row vector.

Returns:

The resulting matrix.

__mul__(self: visp._visp.core.ColVector, M: visp._visp.core.Matrix) -> visp._visp.core.Matrix

Multiply a column vector by a matrix.

Parameters:

M: Matrix.

Returns:

The resulting matrix.

__mul__(self: visp._visp.core.ColVector, x: float) -> visp._visp.core.ColVector

Operator that allows to multiply each element of a column vector by a scalar.

vpColVector v(3);
v[0] = 1;
v[1] = 2;
v[2] = 3;

vpColVector w = v * 3;
// v is unchanged
// w is now equal to : [3, 6, 9]

Parameters:

x: The scalar.

Returns:

The column vector multiplied by the scalar. The current column vector (*this) is unchanged.

__ne__(*args, **kwargs)¶

Overloaded function.

__ne__(self: visp._visp.core.ColVector, v: visp._visp.core.ColVector) -> bool

Compare two column vectors.

Parameters:

v: Vector to compare with.

Returns:

true when their respective size or their values differ, false when their size and values are the same.

__ne__(self: visp._visp.core.ColVector, v: float) -> bool

Compare a column vector to a floating point value.

Parameters:

v: Floating point value to compare with.

Returns:

true when at least one value of the vector differ from the floating point value v . false when all the vector values are equal to v .

__neg__(self) → visp._visp.core.ColVector¶

Operator that allows to negate all the column vector elements.

vpColVector r(3, 1);
// r contains [1 1 1]^T
vpColVector v = -r;
// v contains [-1 -1 -1]^T

__setitem__(*args, **kwargs)¶

Overloaded function.

__setitem__(self: visp._visp.core.ColVector, arg0: int, arg1: float) -> None
__setitem__(self: visp._visp.core.ColVector, arg0: slice, arg1: float) -> None
__setitem__(self: visp._visp.core.ColVector, arg0: slice, arg1: numpy.ndarray[numpy.float64]) -> None

__sub__(self, v: visp._visp.core.ColVector) → visp._visp.core.ColVector¶: Operator subtraction of two vectors this = this - v

__truediv__(self, x: float) → visp._visp.core.ColVector¶

Operator that allows to divide each element of a column vector by a scalar.

vpColVector v(3);
v[0] = 8;
v[1] = 4;
v[2] = 2;

vpColVector w = v / 2;
// v is unchanged
// w is now equal to : [4, 2, 1]

Parameters:

x: float¶: The scalar.

Returns:

The column vector divided by the scalar. The current column vector (*this) is unchanged.

clear(self) → None¶: Removes all elements from the vector (which are destroyed), leaving the container with a size of 0.

static conv2(*args, **kwargs)¶

Overloaded function.

conv2(M: visp._visp.core.ArrayDouble2D, kernel: visp._visp.core.ArrayDouble2D, mode: str) -> visp._visp.core.ArrayDouble2D
conv2(M: visp._visp.core.ArrayDouble2D, kernel: visp._visp.core.ArrayDouble2D, res: visp._visp.core.ArrayDouble2D, mode: str) -> None
conv2(M: visp._visp.core.ArrayDouble2D, kernel: visp._visp.core.ArrayDouble2D, mode: str) -> visp._visp.core.ArrayDouble2D
conv2(M: visp._visp.core.ArrayDouble2D, kernel: visp._visp.core.ArrayDouble2D, res: visp._visp.core.ArrayDouble2D, mode: str) -> None

static cross(a: visp._visp.core.ColVector, b: visp._visp.core.ColVector) → visp._visp.core.ColVector¶

Compute and return the cross product of two 3-dimension vectors: \(a \times b\) .

Note

See crossProd() , dotProd() , operator*(const vpColVector &)

Parameters:

a: visp._visp.core.ColVector¶: 3-dimension column vector.
b: visp._visp.core.ColVector¶: 3-dimension column vector.

Returns:

The cross product \(a \times b\) .

static crossProd(a: visp._visp.core.ColVector, b: visp._visp.core.ColVector) → visp._visp.core.ColVector¶

Compute and return the cross product of two vectors \(a \times b\) .

Note

See dotProd()

Parameters:

a: visp._visp.core.ColVector¶: 3-dimension column vector.
b: visp._visp.core.ColVector¶: 3-dimension column vector.

Returns:

The cross product \(a \times b\) .

deg2rad(self) → visp._visp.core.ColVector¶

Converts a column vector containing angles in degrees into radians and returns a reference to the vector.

Note

See rad2deg()

Returns:: A reference to the vector with values expressed in [rad].

static dotProd(a: visp._visp.core.ColVector, b: visp._visp.core.ColVector) → float¶

Compute end return the dot product of two column vectors:

\[a \cdot b = \sum_{i=0}^n a_i * b_i\]

where n is the dimension of both vectors.

Note

See cross() , crossProd()

extract(self, r: int, colsize: int) → visp._visp.core.ColVector¶

Extract a sub-column vector from a column vector.

vpColVector v1;
for (unsigned int i=0; i<4; ++i)
  v1.stack(i);
// v1 is equal to [0 1 2 3]^T
vpColVector v2 = v1.extract(1, 3);
// v2 is equal to [1 2 3]^T

Parameters:

r: int¶: Index of the row corresponding to the first element of the vector to extract.
colsize: int¶: Size of the vector to extract.

frobeniusNorm(self) → float¶

Compute and return the Frobenius norm \(||v|| = \sqrt{ \sum_{v_{i}^2}}\) of all the elements \(v_{i}\) of the column vector \(\bf v\) that is of dimension \(m\) .

Note

See infinityNorm()

Returns:: The Frobenius norm if the vector is initialized, 0 otherwise.

getCols(self) → int¶: Return the number of columns of the 2D array.

Note

See getRows() , size()

getMaxValue(self) → float¶

getMinValue(self) → float¶

getRows(self) → int¶: Return the number of rows of the 2D array.

Note

See getCols() , size()

hadamard(*args, **kwargs)¶

Overloaded function.

hadamard(self: visp._visp.core.ColVector, v: visp._visp.core.ColVector) -> visp._visp.core.ColVector

Compute the Hadamard product (element wise vector multiplication).

Parameters:

v: Second vector;

Returns:

v1.hadamard(v2) The kronecker product : \(v1 \circ v2 = (v1 \circ v2)_{i} = (v1)_{i} (v2)_{i}\)

hadamard(self: visp._visp.core.ArrayDouble2D, m: visp._visp.core.ArrayDouble2D) -> visp._visp.core.ArrayDouble2D

infinityNorm(self) → float¶

Compute and return the infinity norm \({||v||}_{\infty} = max\left({\mid v_{i} \mid}\right)\) with \(i \in \{0, ..., m-1\}\) where m is the vector size and \(v_i\) an element of the vector.

Note

See frobeniusNorm()

Returns:: The infinity norm if the matrix is initialized, 0 otherwise.

init(self, v: visp._visp.core.ColVector, r: int, nrows: int) → None¶

Initialize the column vector from a part of an input column vector v .

The sub-vector starting from v[r] element and ending on v[r+nrows-1] element is used to initialize the constructed column vector.

The following code shows how to use this function:

#include <visp3/core/vpColVector.h>

#ifdef ENABLE_VISP_NAMESPACE
using namespace VISP_NAMESPACE_NAME;
#endif

int main()
{
  vpColVector v(4);
  int val = 0;
  for(size_t i=0; i<v.getRows(); ++i) {
    v[i] = val++;
  }
  std::cout << "v: " << v.t() << std::endl;

  vpColVector w;
  w.init(v, 0, 2);
  std::cout << "w: " << w.t() << std::endl;
}

It produces the following output:

v: 0 1 2 3
w: 1 2

Parameters:

v: visp._visp.core.ColVector¶: Input column vector used for initialization.
r: int¶: row index in v that corresponds to the first element of the column vector to construct.
nrows: int¶: Number of rows of the constructed column vector.

insert(*args, **kwargs)¶

Overloaded function.

insert(self: visp._visp.core.ColVector, i: int, v: visp._visp.core.ColVector) -> None

Insert a column vector.The following example shows how to use this function:

#include <visp3/core/vpColVector.h>

#ifdef ENABLE_VISP_NAMESPACE
using namespace VISP_NAMESPACE_NAME;
#endif

int main()
{
  vpColVector v(4);
  for (unsigned int i=0; i < v.size(); ++i)
    v[i] = i;
  std::cout << "v: " << v.t() << std::endl;

  vpColVector w(2);
  for (unsigned int i=0; i < w.size(); ++i)
    w[i] = i+10;
  std::cout << "w: " << w.t() << std::endl;

  v.insert(1, w);
  std::cout << "v: " << v.t() << std::endl;
}

It produces the following output:

v: 0 1 2 3
w: 10 11
v: 0 10 11 3

Parameters:

i: Index of the first element to introduce. This index starts from 0.
v: Column vector to insert.

insert(self: visp._visp.core.ArrayDouble2D, A: visp._visp.core.ArrayDouble2D, r: int, c: int) -> None
insert(self: visp._visp.core.ArrayDouble2D, A: visp._visp.core.ArrayDouble2D, B: visp._visp.core.ArrayDouble2D, r: int, c: int) -> visp._visp.core.ArrayDouble2D

static insertStatic(A: visp._visp.core.ArrayDouble2D, B: visp._visp.core.ArrayDouble2D, C: visp._visp.core.ArrayDouble2D, r: int, c: int) → None¶

static invSort(v: visp._visp.core.ColVector) → visp._visp.core.ColVector¶

Return a column vector with elements of v that are reverse sorted with values going from greatest to lowest.

Example:

#include <visp3/core/vpColVector.h>

#ifdef ENABLE_VISP_NAMESPACE
using namespace VISP_NAMESPACE_NAME;
#endif

int main()
{
  vpColVector v(10);
  v[0] = 5; v[1] = 7; v[2] = 4; v[3] = 2; v[4] = 8;
  v[5] = 6; v[6] = 1; v[7] = 9; v[8] = 0; v[9] = 3;

  std::cout << "v: " << v.t() << std::endl;

  vpColVector s = vpColVector::invSort(v);
  std::cout << "s: " << s.t() << std::endl;
}

Output:

v: 5  7  4  2  8  6  1  9  0  3
s: 9  8  7  6  5  4  3  2  1  0

Note

See sort()

static mean(v: visp._visp.core.ColVector) → float¶: Compute the mean value of all the elements of the vector.

static median(v: visp._visp.core.ColVector) → float¶: Compute the median value of all the elements of the vector.

normalize(*args, **kwargs)¶

Overloaded function.

normalize(self: visp._visp.core.ColVector) -> visp._visp.core.ColVector

Normalize the column vector.

Considering the n-dim column vector \({\bf x} = (x_0, x_1, \ldots, n_{n-1})\) normalize each vector element \(i\) :

\[x_i = \frac{x_i}{\sqrt{\sum_{i=0}^{n-1}x^2_i}} \]

Returns:: A reference to the normalized vector.

normalize(self: visp._visp.core.ColVector, x: visp._visp.core.ColVector) -> visp._visp.core.ColVector

Normalize a column vector.

Considering the n-dim column vector \({\bf x} = (x_0, x_1, \ldots, n_{n-1})\) normalize each vector element \(i\) :

\[x_i = \frac{x_i}{\sqrt{\sum_{i=0}^{n-1} x^2_i}} \]

Parameters:

x: As input, the vector to normalize, as output the normalized vector.

Returns:

A reference to the normalized vector.

numpy(self) → numpy.ndarray[numpy.float64]¶: Numpy view of the underlying array data. This numpy view can be used to directly modify the array.

print(self: visp._visp.core.ColVector, s: std::ostream, length: int, intro: str = 0) → int¶

Pretty print a column vector. The data are tabulated. The common widths before and after the decimal point are set with respect to the parameter maxlen.

Note

See std::ostream & operator<<(std::ostream &s, const vpArray2D<Type> &A)

Parameters:

s: Stream used for the printing.
length: The suggested width of each vector element. The actual width grows in order to accommodate the whole integral part, and shrinks if the whole extent is not needed for all the numbers.
intro: The introduction which is printed before the vector. Can be set to zero (or omitted), in which case the introduction is not printed.

Returns:

Returns the common total width for all vector elements.

rad2deg(self) → visp._visp.core.ColVector¶

Note

See deg2rad()

Returns:: A reference to the vector with values expressed in [deg].

reshape(*args, **kwargs)¶

Overloaded function.

reshape(self: visp._visp.core.ColVector, M: visp._visp.core.Matrix, nrows: int, ncols: int) -> None

Reshape the column vector in a matrix.

The following example shows how to use this method.

#include <visp3/core/vpColVector.h>

#ifdef ENABLE_VISP_NAMESPACE
using namespace VISP_NAMESPACE_NAME;
#endif

int main()
{
  int var=0;
  vpMatrix mat(3, 4);
  for (int i = 0; i < 3; ++i)
    for (int j = 0; j < 4; ++j)
      mat[i][j] = ++var;
  std::cout << "mat: \n" << mat << std::endl;

  vpColVector col = mat.stackColumns();
  std::cout << "column vector: \n" << col << std::endl;

  vpMatrix remat = col.reshape(3, 4);
  std::cout << "remat: \n" << remat << std::endl;
}

If you run the previous example, you get:

mat:
1  2  3  4
5  6  7  8
9  10  11  12
column vector:
1
5
9
2
6
10
3
7
11
4
8
12
remat:
1  2  3  4
5  6  7  8
9  10  11  12

Parameters:

M: the reshaped matrix.
nrows: number of rows of the matrix.
ncols: number of columns of the matrix.

reshape(self: visp._visp.core.ColVector, nrows: int, ncols: int) -> visp._visp.core.Matrix

Reshape the column vector in a matrix.

Note

See reshape(vpMatrix &, const unsigned int &, const unsigned int &)

Parameters:

nrows: number of rows of the matrix
ncols: number of columns of the matrix

Returns:

The reshaped matrix.

reshape(self: visp._visp.core.ArrayDouble2D, nrows: int, ncols: int) -> None

resize(*args, **kwargs)¶

Overloaded function.

resize(self: visp._visp.core.ColVector, i: int, flagNullify: bool = true) -> None

Modify the size of the column vector.

Parameters:

i: Size of the vector. This value corresponds to the vector number of rows.
flagNullify: If true, set the data to zero.

resize(self: visp._visp.core.ColVector, nrows: int, ncols: int, flagNullify: bool) -> None

Resize the column vector to a nrows-dimension vector. This function can only be used with ncols = 1.

Parameters:

nrows: Vector number of rows. This value corresponds to the size of the vector.
ncols: Vector number of columns. This value should be set to 1.
flagNullify: If true, set the data to zero.

resize(self: visp._visp.core.ArrayDouble2D, nrows: int, ncols: int, flagNullify: bool = true, recopy_: bool = true) -> None

Set the size of the array and initialize all the values to zero.

Parameters:

nrows: number of rows.
ncols: number of column.
flagNullify: if true, then the array is re-initialized to 0 after resize. If false, the initial values from the common part of the array (common part between old and new version of the array) are kept. Default value is true.
recopy_: if true, will perform an explicit recopy of the old data.

static save(*args, **kwargs)¶

Overloaded function.

save(filename: str, A: visp._visp.core.ArrayDouble2D, binary: bool = false, header: str = ) -> bool
save(filename: str, A: visp._visp.core.ArrayDouble2D, binary: bool = false, header: str = ) -> bool
save(filename: str, A: visp._visp.core.ArrayDouble2D, binary: bool = false, header: str = ) -> bool

static saveYAML(filename: str, A: visp._visp.core.ArrayDouble2D, header: str =) → bool¶

size(self) → int¶: Return the number of elements of the 2D array.

static skew(v: visp._visp.core.ColVector) → visp._visp.core.Matrix¶

Compute the skew symmetric matrix \([{\bf v}]_\times\) of vector v.

\[\begin{split}\mbox{if} \quad {\bf v} = \left( \begin{array}{c} x \\y \\z \end{array}\right), \quad \mbox{then} \qquad [{\bf v}]_\times = \left( \begin{array}{ccc} 0 & -z & y \\z & 0 & -x \\-y & x & 0 \end{array}\right) \end{split}\]

Parameters:

v: visp._visp.core.ColVector¶: Input vector used to compute the skew symmetric matrix.

static sort(v: visp._visp.core.ColVector) → visp._visp.core.ColVector¶

Return a column vector with elements of v that are sorted with values going from lowest to greatest.

Example:

#include <visp3/core/vpColVector.h>

#ifdef ENABLE_VISP_NAMESPACE
using namespace VISP_NAMESPACE_NAME;
#endif

int main()
{
  vpColVector v(10);
  v[0] = 5; v[1] = 7; v[2] = 4; v[3] = 2; v[4] = 8;
  v[5] = 6; v[6] = 1; v[7] = 9; v[8] = 0; v[9] = 3;

  std::cout << "v: " << v.t() << std::endl;

  vpColVector s = vpColVector::sort(v);
  std::cout << "s: " << s.t() << std::endl;
}

Output:

v: 5  7  4  2  8  6  1  9  0  3
s: 0  1  2  3  4  5  6  7  8  9

Note

See invSort()

stack(*args, **kwargs)¶

Overloaded function.

stack(self: visp._visp.core.ColVector, d: float) -> None

Stack column vector with a new element at the end of the vector.

vpColVector v(3, 1);
// v is equal to [1 1 1]^T
v.stack(-2);
// v is equal to [1 1 1 -2]^T

Note

See stack(const vpColVector &, const vpColVector &)

Note

See stack(const vpColVector &, const vpColVector &, vpColVector &)

Parameters:

d: Element to stack to the existing vector.

stack(self: visp._visp.core.ColVector, v: visp._visp.core.ColVector) -> None

Stack column vectors.

vpColVector v1(3, 1);
// v1 is equal to [1 1 1]^T
vpColVector v2(2, 3);
// v2 is equal to [3 3]^T
v1.stack(v2);
// v1 is equal to [1 1 1 3 3]^T

Note

See stack(const vpColVector &, const double &)

Note

See stack(const vpColVector &, const vpColVector &)

Note

See stack(const vpColVector &, const vpColVector &, vpColVector &)

Parameters:

v: Vector to stack to the existing one.

static stackVectors(*args, **kwargs)¶

Overloaded function.

stackVectors(A: visp._visp.core.ColVector, B: visp._visp.core.ColVector) -> visp._visp.core.ColVector

Stack column vectors.

vpColVector A(3);
vpColVector B(5);
vpColVector C;
C = vpColVector::stack(A, B); // C = [A B]T
// C is now an 8 dimension column vector

Note

See stack(const vpColVector &)

Note

See stack(const vpColVector &, const vpColVector &, vpColVector &)

Parameters:

A: Initial vector.
B: Vector to stack at the end of A.

Returns:

Stacked vector \([A B]^T\) .

stackVectors(A: visp._visp.core.ColVector, B: visp._visp.core.ColVector, C: visp._visp.core.ColVector) -> None

Stack column vectors.

vpColVector  A(3);
vpColVector  B(5);
vpColVector  C;
vpColVector::stack (A, B, C); // C = [A B]T
// C is now an 8 dimension column vector

Note

See stack(const vpColVector &)

Note

See stack(const vpColVector &, const vpColVector &)

Parameters:

A: Initial vector.
B: Vector to stack at the end of A.
C: Resulting stacked vector \(C = [A B]^T\) .

static stdev(v: visp._visp.core.ColVector, useBesselCorrection: bool = false) → float¶: Compute the standard deviation value of all the elements of the vector.

strCppCode(self, name: str, byte_per_byte: bool = False) → str¶

Returns a C++ code representation of this data array (see cppPrint in the C++ documentation)

Parameters:

name: str¶: variable name of the matrix.
byte_per_byte: bool = False¶: Whether to print byte per byte defaults to false.

strCsv(self) → str¶: Returns the CSV representation of this data array (see csvPrint in the C++ documentation)

strMaple(self) → str¶: Returns the CSV representation of this data array (see maplePrint in the C++ documentation)

strMatlab(self) → str¶: Returns the Matlab representation of this data array (see matlabPrint in the C++ documentation)

sum(self) → float¶

Return the sum of all the elements \(v_{i}\) of the column vector \(\bf v\) that is of dimension \(m\) .

Returns:: The value

\[\sum_{i=0}^{m-1} v_i \]

sumSquare(self) → float¶

Return the sum of squares of all the elements \(v_{i}\) of the column vector \(\bf v\) that is of dimension \(m\) .

Returns:: The value

\[\sum_{i=0}^{m-1} v_i^{2}\]

t(*args, **kwargs)¶

Overloaded function.

t(self: visp._visp.core.ColVector) -> visp._visp.core.RowVector

Transpose the column vector. The resulting vector becomes a row vector.

t(self: visp._visp.core.ArrayDouble2D) -> visp._visp.core.ArrayDouble2D

toStdVector(self) → list[float]¶

Returns:: The corresponding std::vector<double>.

transpose(*args, **kwargs)¶

Overloaded function.

transpose(self: visp._visp.core.ColVector) -> visp._visp.core.RowVector

Transpose the column vector. The resulting vector becomes a row vector.

Note

See t()

transpose(self: visp._visp.core.ColVector, v: visp._visp.core.RowVector) -> None

Transpose the column vector. The resulting vector v becomes a row vector.

Note

See t()

static view(np_array: numpy.ndarray[numpy.float64]) → visp._visp.core.ColVector¶

Construct a column vector that is a view of a numpy array. When it is modified, the numpy array is also modified. It cannot be resized.

Parameters:

np_array: numpy.ndarray[numpy.float64]¶: The numpy array to copy.

__hash__ = None¶