lorentz-package {lorentz}R Documentation

The Lorentz Transform in Relativistic Physics

Description

The Lorentz transform in special relativity; also the gyrogroup structure of three-velocities. Performs active and passive transforms and has the ability to use units in which the speed of light is not unity. Includes some experimental functionality for celerity and rapidity. For general relativity, see the 'schwarzschild' package.

Details

The DESCRIPTION file:

Package: lorentz
Type: Package
Title: The Lorentz Transform in Relativistic Physics
Version: 1.1-1
Authors@R: person(given=c("Robin", "K. S."), family="Hankin", role = c("aut","cre"), email="hankin.robin@gmail.com", comment = c(ORCID = "0000-0001-5982-0415"))
Suggests: knitr,testthat,rmarkdown,covr
Imports: emulator (>= 1.2-20),tensor,magic,magrittr
Maintainer: Robin K. S. Hankin <hankin.robin@gmail.com>
Description: The Lorentz transform in special relativity; also the gyrogroup structure of three-velocities. Performs active and passive transforms and has the ability to use units in which the speed of light is not unity. Includes some experimental functionality for celerity and rapidity. For general relativity, see the 'schwarzschild' package.
License: GPL-3
Encoding: UTF-8
VignetteBuilder: knitr
URL: https://github.com/RobinHankin/lorentz, https://robinhankin.github.io/lorentz/
BugReports: https://github.com/RobinHankin/lorentz/issues
RoxygenNote: 7.2.3
Author: Robin K. S. Hankin [aut, cre] (<https://orcid.org/0000-0001-5982-0415>)

Index of help topics:

Extract.3vel            Extract or replace parts of three-velocity
Ops.3vel                Arithmetic Ops Group Methods for 3vel objects
as.matrix.3vel          Coerce 3-vectors and 4-vectors to a matrix
boost                   Lorentz transformations
c.3vel                  Combine vectors of three-velocities and
                        four-velocities into a single vector
celerity                Celerity and rapidity
comm_fail               Failure of commutativity and associativity
                        using visual plots
coordnames              Coordinate names for relativity
cosines                 Direction cosines
fourmom                 Four momentum
fourvel                 Four velocities
galileo                 Classical mechanics; Newtonian approximation;
                        infinite speed of light
gam                     Gamma correction
gyr                     Gyr function
lorentz-package         The Lorentz Transform in Relativistic Physics
photon                  Photons
print.3vel              Print methods for three-velocities and
                        four-velocities
r3vel                   Random relativistic velocities
reflect                 Mirrors
seq.3vel                seq method for three velocities
sol                     Speed of light and Minkowski metric
threevel                Three velocities
transform               The energy-momentum tensor

Author(s)

Robin K. S. Hankin [aut, cre] (<https://orcid.org/0000-0001-5982-0415>)

Maintainer: Robin K. S. Hankin <hankin.robin@gmail.com>

References

Examples


u <- as.3vel(c(0.3,0.6,-0.1))  # u is a three-velocity
gam(u)                         # relativistic gamma term for u
U <- as.4vel(u)                # U is a four-velocity
B1 <- boost(u)                 # B1 is the Lorentz transform matrix for u
B1 %*% c(1,0,0,0)              # Lorentz transform of zero 4-velocity (=-u)

B2 <- boost(as.3vel(c(-0.1,0.8,0.3)))  
B3 <- boost(as.3vel(c(-0.1,0.1,0.9)))  # more boosts

Bi <- B1 %*% B2  # Bi is the boost for successive Lorentz transforms


pureboost(Bi)      # Decompose Bi into a pure boost...
orthog(Bi)         # and an orthogonal matrix

Bj <- B2 %*% B1    # B1 and B2 do not commute...

(B1 %*% B2) %*% B3 
B1 %*% (B2 %*% B3)    # ...but composition *is* associative



## Three velocities and the gyrogroup

## Create some random three-velocities:

u <- r3vel(10)
v <- r3vel(10)
w <- r3vel(10)

u+v
v+u        # Three-velocity addition is not commutative...

u+(v+w)   # ... nor associative
(u+v)+w 


[Package lorentz version 1.1-1 Index]