complex                 package:base                 R Documentation

_C_o_m_p_l_e_x _V_e_c_t_o_r_s

_D_e_s_c_r_i_p_t_i_o_n:

     Basic functions which support complex arithmetic in R.

_U_s_a_g_e:

     complex(length.out = 0, real = numeric(), imaginary = numeric(),
             modulus = 1, argument = 0)
     as.complex(x, ...)
     is.complex(x)

     Re(x)
     Im(x)
     Mod(x)
     Arg(x)
     Conj(x)

_A_r_g_u_m_e_n_t_s:

length.out: numeric.  Desired length of the output vector, inputs being
          recycled as needed.

    real: numeric vector.

imaginary: numeric vector.

 modulus: numeric vector.

argument: numeric vector.

       x: an object, probably of mode 'complex'.

     ...: further arguments passed to or from other methods.

_D_e_t_a_i_l_s:

     Complex vectors can be created with 'complex'.  The vector can be
     specified either by giving its length, its real and imaginary
     parts, or modulus and argument.  (Giving just the length generates
     a vector of complex zeroes.)

     'as.complex' attempts to coerce its argument to be of complex
     type: like 'as.vector' it strips attributes including names.

     Note that 'is.complex' and 'is.numeric' are never both 'TRUE'.

     The functions 'Re', 'Im', 'Mod', 'Arg' and 'Conj' have their usual
     interpretation as returning the real part, imaginary part,
     modulus, argument and complex conjugate for complex values. 
     Modulus and argument are also called the _polar coordinates_.  If
     z = x + i y with real x and y, for r = 'Mod'(z) = sqrt{x^2 + y^2},
     and phi = 'Arg'(z), x = r*cos(phi) and y = r*sin(phi). They are
     all generic functions: methods can be defined for them
     individually or via the 'Complex' group generic.

     In addition, the elementary trigonometric, logarithmic and
     exponential functions are available for complex values.

     'is.complex' is generic: you can write methods to handle specific
     classes of objects, see InternalMethods.

_R_e_f_e_r_e_n_c_e_s:

     Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) _The New S
     Language_. Wadsworth & Brooks/Cole.

_E_x_a_m_p_l_e_s:

     0i ^ (-3:3)

     matrix(1i^ (-6:5), nr=4)#- all columns are the same
     0 ^ 1i # a complex NaN

     ## create a complex normal vector
     z <- complex(real = rnorm(100), imag = rnorm(100))
     ## or also (less efficiently):
     z2 <- 1:2 + 1i*(8:9)

     ## The Arg(.) is an angle:
     zz <- (rep(1:4,len=9) + 1i*(9:1))/10
     zz.shift <- complex(modulus = Mod(zz), argument= Arg(zz) + pi)
     plot(zz, xlim=c(-1,1), ylim=c(-1,1), col="red", asp = 1,
          main = expression(paste("Rotation by "," ", pi == 180^o)))
     abline(h=0,v=0, col="blue", lty=3)
     points(zz.shift, col="orange")

