all functions - z

             zncen(ptcen)  
          or zncen(ptcen, ireg)  
 
     returns zone centered version of the 2-D point centered array PTCEN.  
     The result is (imax-1)-by-(jmax-1) if PTCEN is imax-by-jmax.  
     If the region number array IREG is specified, zones with region  
     number 0 are not included in the point centering operation.  
     Note that IREG should have dimensions imax-by-jmax, like  
     the input PTCEN array; the first row and column of IREG are ignored.  
     Without IREG, zncen(ptcen) is equivalent to ptcen(zcen,zcen).  
interpreted function, defined at i0/std.i   line 2879  

             zoom_factor, factor  
 
     sets the zoom factor for mouse-click zoom in and zoom out operations.  
     The default FACTOR is 1.5; FACTOR should always be greater than 1.0.  
builtin function, documented at i0/graph.i   line 843  

 zpad  
 
  
interpreted function, defined at contrib/split.i   line 3  

             zroots(a)  
 
     returns the vector of (complex) roots of the (complex)   
     polynomial: Sum(a(i)*x^(i-1)) using Laguerre's method.  
     The roots are sorted in order of increasing real parts.  Call with  
     non-zero imsort keyword to sort into increasing imaginary parts.  
     See Numerical Recipes (Press, et. al., Cambridge Univ. Press 1988),  
     section 9.5.  
interpreted function, defined at i/zroots.i   line 10