[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: casting

From: Søren Hauberg
Subject: Re: casting
Date: Tue, 13 Mar 2007 09:40:48 +0100
User-agent: Thunderbird (X11/20070307)

John W. Eaton skrev:
On 12-Mar-2007, David Grohmann wrote:

| | Thank you. I will give that a shot. | | Søren Hauberg wrote:
| > How about this function:
| >
| > function B = cast(A, newclass)
| >   B = feval(newclass, A);
| > endfunction

To avoid the feval and to also be able to detect invalid class names,
I used the following:

function retval = cast (val, typ)

  if (nargin == 2)
    if (ischar (typ))
      switch (typ)
        case "int8"
          retval = int8 (val);
        case "uint8"
          retval = uint8 (val);
        case "int16"
          retval = int16 (val);
        case "uint16"
          retval = uint16 (val);
        case "int32"
          retval = int32 (val);
        case "uint32"
          retval = uint32 (val);
        case "int64"
          retval = int64 (val);
        case "uint64"
          retval = uint64 (val);
        case "double"
          retval = double (val);
        case "single"
          retval = single (val);
          error ("cast: invalid type name `%s'", typ);
      error ("cast: expecting type name as second argument");
    print_usage ();

Just a few stupid questions :-)
Is feval really so slow that you switch-case is faster? If I had to do input checking in my code I would just have added something like

if (!any(strcp(typ, {"int8", "int16", "uint8", (you get the idea...)})))
  error("cast: second argument must be the name of a builtin type");

followed be the call to feval. I would just guess that it's more easy to maintain because it's less code.

Also, I that you handle the "single" type in your code. Does octave support "single" now?

Is the "cast" function in cvs now?


reply via email to

[Prev in Thread] Current Thread [Next in Thread]