tractor.base (version 2.3.0)

vector functions: Miscellaneous vector functions

Description

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

Usage

vectorLength(vector)
vectorCrossProduct(a, b)
angleBetweenVectors(v1, v2)
resolveVector(len, ...)

Arguments

vector, v1, v2

Numeric vectors of any length.

a, b

Numeric 3-vectors.

len

The expected length of the vector.

...

Elements of the vector, to be concatenated together.

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.

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/.

See Also

crossprod for the matrix cross product.