resolveVector {tractor.base}

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. doi:10.18637/jss.v044.i08.

See Also

crossprod for the matrix cross product.