From octave-sources-request at bevo dot che dot wisc dot edu  Thu Oct  1 22:49:12 1998
Subject: new function: is_complex 
From: "John W. Eaton" <jwe at bevo dot che dot wisc dot edu>
To: Erik de Castro Lopo <erikd at zip dot com dot au>
Cc: octave-sources at bevo dot che dot wisc dot edu
Date: Thu, 1 Oct 1998 22:47:54 -0500 (CDT)

On  2-Oct-1998, Erik de Castro Lopo <erikd at zip dot com dot au> wrote:

| I found a need for a function to tell me is a vector
| or matrix had any complex components. I took the
| sources for is_vector our of 
| 
| 	/usr/local/share/octave/2.0.13/m/general/
| 
| and modified it as follows. I'll leave it with John's
| copyright as I really don't feel I did enough to warant
| putting my name on it. 
| 
| I do hwoever think that this is probably useful enough 
| to place in the standard distribution.

Thanks for the code.  I think the following is a bit better.  It will
work correctly even for structures and user-defined types that may
give error messages when passed to imag(), and it will also be much
faster for large matrices.

jwe

*** src/data.cc~	Mon Apr 20 22:29:48 1998
--- src/data.cc	Thu Oct  1 22:39:27 1998
***************
*** 739,744 ****
--- 739,757 ----
    return retval;
  }
  
+ DEFUN (is_complex, args, ,
+   "is_complex (x): return nonzero if x is a complex numeric object")
+ {
+   octave_value retval;
+ 
+   if (args.length () == 1)
+     retval = args(0).is_complex_type () ? 1.0 : 0.0;
+   else
+     print_usage ("is_struct");
+ 
+   return retval;
+ }
+ 
  DEFUN (is_struct, args, ,
    "is_struct (x): return nonzero if x is a structure")
  {