variable directional stretching of a complex vector
Y=dirstretch(X,D) Y=dirstretch(X,DIR,COEF)
dirstretch(X,D) where X is a complex vector and D a complex scalar stretches X by abs(D) along the direction arg(D) if D is a vector the same size as X, then X(i) is stretched by abs(D(i)) along the direction arf(D(i))
dirstretch(X,DIR,COEF) where X is a complex vector, DIR is either a unit modulus complex number or a real number and COEF a real number stretches X by COEF along the direction DIR (or EXP(I*DIR) if DIR is real) if DIR and/or COEF is a vector the same size as X, then X(i) is stretched by COEF(i) along the direction DIR(i) (or EXP(I*DIR(i)))