Conversion between the circular SD and kappa of von Mises

vm_kappa_to_circ_sd(kappa)

vm_kappa_to_circ_sd_deg(kappa)

vm_circ_sd_to_kappa(sd)

vm_circ_sd_deg_to_kappa(sd_deg)

Arguments

kappa: von Mises kappa parameter
sd: circular SD of von Mises (radians)
sd_deg: circular SD of von Mises (degrees)

Value

vm_kappa_to_circ_sd and vm_kappa_to_circ_sd_deg return circular SD (in radians or degrees, respectively) corresponding to a given kappa. vm_circ_sd_to_kappa and vm_circ_sd_deg_to_kappa return kappa corresponding to a given circular SD (in radians or degrees, respectively).

Functions

vm_kappa_to_circ_sd_deg(): get circular SD (in degrees) from kappa
vm_circ_sd_to_kappa(): get kappa from circular SD (in radians)
vm_circ_sd_deg_to_kappa(): get kappa from circular SD (in degrees)

Examples


vm_kappa <- 5
vm_sd <- vm_kappa_to_circ_sd(vm_kappa)

vm_circ_sd_to_kappa(vm_sd)
#> [1] 5

x <- circular::rvonmises(10000, mu = circular::circular(0), kappa = vm_kappa)

sprintf('Expected SD: %.2f, actual SD: %.2f', vm_sd, circ_sd_rad(x))
#> [1] "Expected SD: 0.47, actual SD: 0.48"