About vector class
In order to use the vector class, you include the header file
depending on the dimension:N ( N = 2, 3, 4 ).
| Header: | #include <kvs/VectorN> |
And, you declare a variable depending on the type:T ( T = i, ui, f, d).
| Variable x: | kvs::VectorNT x; |
Here, the abbreviation of type name defines as follows:
| i | int | |
| ui | unsigned int | |
| f | float | |
| d | double |
Moreover, you can use following abbreviation :
| VecN | float | |
| VecNi | int | |
| VecNui | unsigned int |
The abbreviation type:
kvs::Vector3f a;
kvs::Vec3 a;
is same as follows:
kvs::Vector3<float> a;
Member functions
Constructor
There are four-type of constructor.
Following example explains the constructor case of "kvs::Vector3i"
( Notie that the initial value sets to zero in case of the default constructor )
// Default constructor
kvs::Vector3i a;
// assign all component
kvs::Vector3i b( 1, 2, 0 );
// 2-D vector (kvs::Vector2i) and 3rd component
lvs::Vector2i t( 1, 1); // 2-D vector
kvs::Vector3i c( t, 3 );
// 3-D array
int element[3] = {1, 2, 3 };
kvs::Vector3i d( element );
Value substitution: Operator [ ], zero( ), set( )
Operator [] : same as arrays
zero(): all components of vector sets to ZERO
set( kvs::Vector2T, T x), set( T x[3] ):
components of vector set to the arguments of a function
// Operator []
a[0] = 1; a[1] = 10; a[2] =5;
// Zero clear
a.zero( );
// method set(): all components
a.set( 1, 2, 2 );
// method set(): 2-D vector + 3rd component
lvs::Vector2i t( 1, 1);
a.set( t, 5 );
// method set(): 3-D array
int element[3] = { 1, 2, 3 };
a.set( element );
Static member function to clear all component: Zero( ), All( )
Zero(): all components of a vector sets to ZERO
All( Type x ): all components of a vector sets to x
//Zero Clear
a = kvs::Vector3f::Zero( );
//All components set to 3.0
a = kvs::Vector3f::All( 3.0 );
Getting value: Operator [ ], x( ), y( ), z( )
Operator []: same as arrays
x(), y(), z() : getting the components x, y, z
// Operator []
int x0, y0, z0;
x0 = a[0]; y0 = a[1]; z0 = a[2];
// Component x, y, z
std::cout << a.x( ) << ", " << a.y( ) << ", " << a.z( ) << std::endl;
Here, a[0] is equal to a.x().
Standard output: print( ), output operator<<
a.print( );
std::cout << a;
Above example is same output:
1 2 3
Normalization: normalize( ), normalized( )
normalize( ): superscription (normalize own)
normalized( ): normalized vector returns (the own value does not change)
// Superscription
kvs::Vector3d x( 1.0, 2.0, 3.0 );
x.normalize( );
// Return the normalized vector
kvs::Vector3d y( 1.0, 2.0, 3.0 );
kvs::Vector3d z = y.normalized( );
Length: length( ), length2( )
length(): length of vector
length2(): square of the length
Here, length() and length2() function have a return type of double.
// Length of vector
double v0 = y.length( );
// Square of the length
double w0 = y.length2( );
Four arithmetic operations： +, -, *, /
Vector Addition and Subtraction are defined as
Operator + (+=) and Operator - ( -= ), respectively.
a.set( 1, 1, 1 );
b.set( 3, 4, 5 );
c = a + b;
a+=c;
a -= b;
std::cout << -a << std::endl;
Operator * ( *= ) multiply by scalar value or vector. In the case of multipling by vector, the product of each component is calculated.
// Multiply by vector
a*=b;
// Multiply by scalar value
int i0 = 10;
c = i0*b;
c = b*i0;
c *= i0;
Operator / (/= ) divide by scalar value or vector,
d = c/i0;
c /= i0;
Inner product: dot( ), Cross product: cross( ), Swap: swap( )
For example:
// Inner product
int dot = a.dot( b );
// Cross product
c = a.cross( b );
// Swap
x.swap( y );
Relational operator: ==, !=
Relational operator compares each component.
For exampe:
// Relational operator
if( a == b ) {
std::cout << "a == b" << std::endl;
}
else if( a != b ) {
std::cout << "a != b" << std::endl; }
Sample program: VectorTest.tgz
Compile and execute
Let's try to compile and execute above program.
When compiling a KVS program, it is easy to use the automatic Makefile-generation tool kvsmake supplied by KVS.
Here, the option “-G” defines the name of executable file same as the name of current directory.
# kvsmake -G <-- Generate Makefile
# kvsmake <-- Compile
And then,
# ./VectorTest
Last Updated at Nov. 1, 2015