R: Miscellaneous vector functions

resolveVector {tractor.base}

R Documentation

Miscellaneous vector functions

Description

These functions provide the (Euclidean) length of a vector, the vector cross product or angle between two vectors.

Usage

resolveVector(len, ...)

vectorLength(vector)

vectorCrossProduct(a, b)

angleBetweenVectors(v1, v2)

Arguments

`len`	The expected length of the vector.
`...`	Elements of the vector, to be concatenated together.
`vector, v1, v2`	Numeric vectors of any length.
`a, b`	Numeric 3-vectors.

Value

For vectorLength, the Euclidean norm or length of the specified vector, given by sqrt(sum(vector^2)). For vectorCrossProduct, the vector cross product of the two specified vectors; and for angleBetweenVectors, the angle (in radians) between the two specified vectors. The resolveVector function concatenates the values given in ...{}, and if the result is a vector of length len then it is returned. If not, NULL is returned.

Author(s)

Jon Clayden

References

Please cite the following reference when using TractoR in your work:

J.D. Clayden, S. Muñoz Maniega, A.J. Storkey, M.D. King, M.E. Bastin & C.A. Clark (2011). TractoR: Magnetic resonance imaging and tractography with R. Journal of Statistical Software 44(8):1-18. http://www.jstatsoft.org/v44/i08/.