Vector Classes

There are two vector classes available in Hydra, namely Vector4R and Vector3R.

Vector4R

The Vector4R class available in Python wraps the C++ Vector4R class representing four-dimensional relativistic vectors. Three types of constructors allow to instantiate the Vector4R class:

• Default empty constructor.
• Copy constructor.
• Constructor from 4 real (float) numbers.

import HydraPython as hp

vec1 = hp.Vector4R()  # construction with values 0.0 for all 4 particals
vec2 = hp.Vector4R(0.8385, 0.1242, 0.9821, 1.2424)
vec3 = hp.Vector4R(vec2)  # Copy construct the vec3 from vec2

print (vec1)  # (0, 0, 0, 0)
print (vec2)  # (0.8385,0.1242,0.9821,1.2424)
print (vec3)  # (0.8385,0.1242,0.9821,1.2424)

The Vector4R class also provides a pretty convenient method to create an instance from a python list.

list_ = [0.9241, 0.13223, 0.13121, 1.1141]
vec4 = hp.Vector4R(list_)

This will construct a new Vector4R object with the values passed within a list. The list should contain exactly 4 elements otherwise a TypeError will be raised. The set methods can be used to set all 4 values or a particular value in a Vector4R object, while the get method can be used with Vector4R to get the value of a particular index. The __getitem__ and __setitem methods can also be used to get or set the value which comes very handy and maintain more pythonic way to access and set the values.

vec5 = hp.Vector4R(0.8385, 0.1242, 0.9821, 1.2424)
print (vec5)  # (0.8385,0.1242,0.9821,1.2424)

vec5.set(0, 0.9887)
print (vec5)  # (0.9887,0.1242,0.9821,1.2424)

vec5.set(0.1234, 0.5118, 0.9101, 0.1121)
print (vec5)  # (0.1234,0.5118,0.9101,0.1121)

print (vec5[1])  # 0.5118
print (vec5.get(1))  # 0.5118
vec5[1] = 0.5678
print (vec5)  # (0.1234,0.5678,0.9101,0.1121)

The Vector4R object can be multiplied or divided by a real value while it can be added or subtracted with another Vector4R object. One Vector4R object can be multiplied by another Vector4R object.

vec6 = hp.Vector4R(0.8215, 0.9241, 0.0105, 1.1994)
vec6 *= 1.1
print (vec6)  # (0.90365,1.01651,0.01155,1.31934)
vec6 /= 0.6
print (vec6)  # (1.50608,1.69418,0.01925,2.1989)

vec7 = hp.Vector4R(0.1223, 0.6433, 0.1234, 0.3010)
vec6 += vec7  # Add vec6 with the values of vec7
print (vec6)  # (1.62838,2.33748,0.14265,2.4999)

vec6 -= vec7
print (vec6)  # (1.50608,1.69418,0.01925,2.1989)

Two Vector4R objects can easily be added, subtracted or multiplied:

• v = v1 + v2 # Returns a Vector4R object
• v = v1 - v2 # Returns a Vector4R object
• v = v1 * v2 # Returns a real number

All above three are valid for any Vector4R object. There are various other methods available in Vector4R. The list of Vector4R methods can be found on [1].

The Vector4R provides an assign method to assign or copy the Vector4R object. This is a very useful method to avoid the nasty bugs for example:

vec = hp.Vector4R(0.2010, 0.3010, 0.0210, 0.8385)
vec2 = hp.Vector4R()

# Do things and later in code ...
vec2.assign(vec)
vec == vec2  # True since all values are equal
vec is vec2  # False

vec = vec2   # Reference is copied
vec == vec2  # True
vec is vec2  # True

Vector3R

The Vector43 class available in Python wraps the C++ Vector3R class representing three-dimensional Euclidian vectors. Three types of constructors allow to instantiate the Vector3R class:

• Default empty constructor.
• Copy constructor.
• Constructor from 3 real (float) numbers.

import HydraPython as hp

vec1 = hp.Vector3R()  # construction with values 0.0 for all 3 particals
vec2 = hp.Vector3R(0.8385, 0.1242, 0.9821)
vec3 = hp.Vector3R(vec2)  # Copy construct the vec3 from vec2

print (vec1)  # (0,0,0)
print (vec2)  # (0.8385,0.1242,0.9821)
print (vec3)  # (0.8385,0.1242,0.9821)

The Vector3R class also provides a pretty convenient method to create an object from python list.

list_ = [0.9241, 0.13223, 0.13121]
vec4 = hp.Vector3R(list_)

This will construct a new Vector3R object with the values passed within a list. The list should contain exactly 3 elements otherwise a TypeError will be raised. The set methods can be used to set all 3 values or a particular value in a Vector3R object, while the get method can be used with Vector3R to get the value of a particular index. The __getitem__ and __setitem methods can also be used to get or set the value which comes very handy and maintain more pythonic way to access and set the values.

vec5 = hp.Vector3R(0.8385, 0.1242, 0.9821)
print (vec5)  # (0.8385,0.1242,0.9821)

vec5.set(0, 0.9887)
print (vec5)  # (0.9887,0.1242,0.9821)

vec5.set(0.1234, 0.5118, 0.9101)
print (vec5)  # (0.1234,0.5118,0.9101)

print (vec5[1])  # 0.5118
print (vec5.get(1))  # 0.5118
vec5[1] = 0.5678
print (vec5)  # (0.1234,0.5678,0.9101)

The Vector3R object can be multiplied or divided by a real value while it can be added or subtracted with another Vector3R object. One Vector3R object can be multiplied by another Vector3R object.

vec6 = hp.Vector3R(0.8215, 0.9241, 0.0105)
vec6 *= 1.1
print (vec6)  # (0.90365,1.01651,0.01155)
vec6 /= 0.6
print (vec6)  # (1.50608,1.69418,0.01925)

vec7 = hp.Vector3R(0.1223, 0.6433, 0.1234)
vec6 += vec7  # Add vec6 with the values of vec7
print (vec6)  # (1.62838,2.33748,0.14265)

vec6 -= vec7
print (vec6)  # (1.50608,1.69418,0.01925)

Two Vector3R objects can easily be added, subtracted or multiplied:

• v = v1 + v2 # Returns a Vector3R object
• v = v1 - v2 # Returns a Vector3R object
• v = v1 * v2 # Returns a real number

All above three are valid for any Vector3R object. There are various other methods available in Vector3R. The list of Vector3R methods can be found on [2].

The Vector3R provides an assign method to assign or copy the Vector3R object. This is a very useful method to avoid the nasty bugs for example:

vec = hp.Vector3R(0.2010, 0.3010, 0.0210)
vec2 = hp.Vector3R()

# Do things and later in code ...
vec2.assign(vec)
vec == vec2  # True since all values are equal
vec is vec2  # False

vec = vec2   # Reference is copied
vec == vec2  # True
vec is vec2  # True

[1]

The method list for Vector4R set Set the value at an index or all 4 values of Vector4R. Syntax: vec1.set(idx, float) vec1.set(float, float, float, float) get Get the value at an index for a Vector4R. Syntax: vec1.get(idx) assign Assigns one Vector4R content to other Vector4R. Syntax: vec1.assign(vec2) cont Finds the cont of the Vector4R object. Syntax: result = vec1.cont(vec2) mass Returns the mass of the Vector4R object. Syntax: result = vec1.mass() mass2 Returns the mass2 of the Vector4R object. Syntax: result = vec1.mass() applyRotateEuler Apply the rotate Eular on given Vector4R object. Syntax: vec1.applyRotateEuler(float, float, float) applyBoostTo Apply the boost on the given Vector4R object. Syntax: vec1.applyBoostTo(vec2, bool) vec1.applyBoostTo(Vector3R, bool) # Pay attention to Vector3R object vec1.applyBoostTo(float, float, float, bool) cross Returns the cross product of two Vector4R. Syntax: result_vector = vec1.cross(vec2) dot Returns the dot product of two Vector4R. Syntax: result = vec1.dot(vec2) d3mag Returns the d3mag for two Vector4R. Syntax: result = vec1.d3mag() dotr3 Returns the dot product of three Vector4R. Syntax: result = vec1.dotr3(vec2, vec3) mag2r3 Returns the mag2r3 of two Vector4R. Syntax: result = vec1.mag2r3(vec2) magr3 Returns the magr3 of two Vector4R. Syntax: result_vector = vec1.magr3(vec2)

[2]

The method list for Vector3R set Set the value at an index or all 3 values of Vector3R. Syntax: vec1.set(idx, float) vec1.set(float, float, float) get Get the value at an index for a Vector3R. Syntax: vec1.get(idx) assign Assigns one Vector4R content to other Vector3R. Syntax: vec1.assign(vec2) dot Returns the dot product of two Vector3R. Syntax: result = vec1.dot(vec2) d3mag Returns the d3mag for two Vector3R. Syntax: result = vec1.d3mag()