arr.hpp File Reference

Minimal flat-vector array class replacing xtensor for small optimization problems. More...

#include <cassert>
#include <cmath>
#include <cstdint>
#include <initializer_list>
#include <numeric>
#include <utility>
#include <vector>

Include dependency graph for arr.hpp:

Go to the source code of this file.

Classes
class	Arr
	1D or 2D array backed by std::vector<double> for small optimization problems More...
struct	Range
	Index range [start, end) with step for slicing views. More...

Functions
Arr	view (const Arr &a, const Range &rows, const Range &cols)
	Extract a submatrix view from a 2D array using Range for rows and cols.
Arr	view (const Arr &a, const Range &rows)
	Extract a subarray view (1D or 2D) using a single Range.
Arr	zeros (size_t n)
	Create zero-initialized 1D array of size n.
Arr	zeros (size_t r, size_t c)
	Create zero-initialized 2D array with r rows, c columns.
Arr	ones (size_t r, size_t c)
	Create 2D array of ones with r rows, c columns.
Arr	linspace (double start, double end, size_t n)
	Linearly spaced values from start to end, inclusive.
Arr	arange (double start, double end)
	Values from start to end-1 with step 1.
Arr	make_same_shape (const Arr &a)
	Create a zero-initialized Arr with the same shape as input.
Arr	cos (const Arr &a)
	Element-wise cosine.
Arr	log (const Arr &a)
	Element-wise natural logarithm.
Arr	abs (const Arr &a)
	Element-wise absolute value.
Arr	exp (const Arr &a)
	Element-wise exponential.
Arr	sqrt (const Arr &a)
	Element-wise square root.
double	sum (const Arr &a)
	Sum of all elements.
std::vector< Arr >	where (const Arr &condition)
	Find indices of non-zero elements.
Arr	dot (const Arr &A, const Arr &x)
	Matrix-vector multiplication.
Arr	outer (const Arr &u, const Arr &v)
	Outer product of two 1D vectors.
Arr	concatenate (const Arr &a, const Arr &b, int=1)
	Concatenate two 2D arrays along columns (axis=1)
Arr	operator- (const Arr &a)
	Unary negation (element-wise)
Arr	operator+ (const Arr &a, const Arr &b)
	Element-wise addition of two arrays.
Arr	operator- (const Arr &a, const Arr &b)
	Element-wise subtraction of two arrays.
Arr	operator* (const Arr &a, const Arr &b)
	Element-wise multiplication of two arrays.
Arr	operator* (double s, const Arr &a)
	Scalar multiplication (scalar × array)
Arr	operator* (const Arr &a, double s)
	Scalar multiplication (array × scalar)
Arr	operator/ (const Arr &a, double s)
	Scalar division (array / scalar)
Arr	operator<= (const Arr &a, double s)
	Element-wise less-than-or-equal-to comparison with scalar.
Arr	operator>= (const Arr &a, double s)
	Element-wise greater-than-or-equal-to comparison with scalar.
Arr	operator< (const Arr &a, double s)
	Element-wise less-than comparison with scalar.
Arr	operator> (const Arr &a, double s)
	Element-wise greater-than comparison with scalar.
Arr	eval (Arr a)
	Identity function for Arr (for API compatibility)

Variables
constexpr size_t	ALL = Range::ALL
	Convenience alias for Range::ALL.

Detailed Description

Minimal flat-vector array class replacing xtensor for small optimization problems.

Supports 1D (vector) and 2D (row-major matrix) with operations needed by ellipsoid-method-based solvers. Not a general-purpose array library.

Function Documentation

abs()

Arr abs ( const Arr &  a )

inline

Element-wise absolute value.

arange()

Arr arange ( double  start, double  end  )

inline

Values from start to end-1 with step 1.

Returns

1D Arr containing [start, start+1, ..., end-1]

concatenate()

Arr concatenate ( const Arr &  a, const Arr &  b, int  = 1  )

inline

Concatenate two 2D arrays along columns (axis=1)

Parameters

[in]	a	Left 2D array
[in]	b	Right 2D array

Returns

2D array with rows = a.rows(), cols = a.cols() + b.cols()

cos()

Arr cos ( const Arr &  a )

inline

Element-wise cosine.

dot()

Arr dot ( const Arr &  A, const Arr &  x  )

inline

Matrix-vector multiplication.

\[ y = A x, \qquad y_i = \sum_{j=1}^{n} A_{ij} x_j \]

Parameters

[in]	A	2D matrix (m × n)
[in]	x	1D vector (n)

Returns

Result vector (m)

eval()

Arr eval ( Arr  a )

inline

Identity function for Arr (for API compatibility)

exp()

Arr exp ( const Arr &  a )

inline

Element-wise exponential.

linspace()

Arr linspace ( double  start, double  end, size_t  n  )

inline

Linearly spaced values from start to end, inclusive.

\[ x_i = x_{\text{start}} + i \cdot \frac{x_{\text{end}} - x_{\text{start}}}{n - 1}, \qquad i = 0, \dots, n-1 \]

Parameters

[in]	start	First value
[in]	end	Last value
[in]	n	Number of points

Returns

1D Arr of n equally spaced values

log()

Arr log ( const Arr &  a )

inline

Element-wise natural logarithm.

make_same_shape()

Arr make_same_shape ( const Arr &  a )

inline

Create a zero-initialized Arr with the same shape as input.

ones()

Arr ones ( size_t  r, size_t  c  )

inline

Create 2D array of ones with r rows, c columns.

operator*() [1/3]

Arr operator* ( const Arr &  a, const Arr &  b  )

inline

Element-wise multiplication of two arrays.

operator*() [2/3]

Arr operator* ( const Arr &  a, double  s  )

inline

Scalar multiplication (array × scalar)

operator*() [3/3]

Arr operator* ( double  s, const Arr &  a  )

inline

Scalar multiplication (scalar × array)

operator+()

Arr operator+ ( const Arr &  a, const Arr &  b  )

inline

Element-wise addition of two arrays.

operator-() [1/2]

Arr operator- ( const Arr &  a )

inline

Unary negation (element-wise)

operator-() [2/2]

Arr operator- ( const Arr &  a, const Arr &  b  )

inline

Element-wise subtraction of two arrays.

operator/()

Arr operator/ ( const Arr &  a, double  s  )

inline

Scalar division (array / scalar)

operator<()

Arr operator< ( const Arr &  a, double  s  )

inline

Element-wise less-than comparison with scalar.

Returns

Arr of 1.0/0.0 indicating true/false

operator<=()

Arr operator<= ( const Arr &  a, double  s  )

inline

Element-wise less-than-or-equal-to comparison with scalar.

Returns

Arr of 1.0/0.0 indicating true/false

operator>()

Arr operator> ( const Arr &  a, double  s  )

inline

Element-wise greater-than comparison with scalar.

Returns

Arr of 1.0/0.0 indicating true/false

operator>=()

Arr operator>= ( const Arr &  a, double  s  )

inline

Element-wise greater-than-or-equal-to comparison with scalar.

Returns

Arr of 1.0/0.0 indicating true/false

outer()

Arr outer ( const Arr &  u, const Arr &  v  )

inline

Outer product of two 1D vectors.

\[ C = u \otimes v, \qquad C_{ij} = u_i v_j \]

Parameters

[in]	u	First 1D vector
[in]	v	Second 1D vector

Returns

2D matrix where result(i,j) = u(i) × v(j)

sqrt()

Arr sqrt ( const Arr &  a )

inline

Element-wise square root.

sum()

double sum ( const Arr &  a )

inline

Sum of all elements.

view() [1/2]

Arr view ( const Arr &  a, const Range &  rows  )

inline

Extract a subarray view (1D or 2D) using a single Range.

Parameters

[in]	a	Input array (1D or 2D)
[in]	rows	Row range (or element range for 1D)

Returns

New Arr containing the subarray

view() [2/2]

Arr view ( const Arr &  a, const Range &  rows, const Range &  cols  )

inline

Extract a submatrix view from a 2D array using Range for rows and cols.

Parameters

[in]	a	Input 2D array
[in]	rows	Row range [start, end, step]
[in]	cols	Column range [start, end, step]

Returns

New Arr containing the submatrix

where()

std::vector< Arr > where ( const Arr &  condition )

inline

Find indices of non-zero elements.

Parameters

[in]

condition

Input 1D array (non-zero = true)

Returns

Vector containing [indices] as a 1D Arr

zeros() [1/2]

Arr zeros ( size_t  n )

inline

Create zero-initialized 1D array of size n.

zeros() [2/2]

Arr zeros ( size_t  r, size_t  c  )

inline

Create zero-initialized 2D array with r rows, c columns.

Variable Documentation

ALL

constexpr size_t ALL = Range::ALL

inlineconstexpr

Convenience alias for Range::ALL.