R help - May 2000 - coercing NA to complex?

I struck a problem concatenating two complex vectors with an NA for 
plotting purposes.  It seems that NA is not automatically coerced to mode 
complex. In the complex vector "b" below, an NA appears after half the
vector, and a zero appears where the NA should be:

3+4i 3+4i  NA 3+4i 0+0i 3+4i 3+4i 3+4i 3+4i 285

This zero seems to coming from free space, as, after running this example 
a few times, the zero gets replaced by some sort of erratic garbage: 

3+4i 3+4i  NA 3+4i 2.466318e+179+6.800902e+199i 3+4i 3+4i 3+4i 3+4i 292 

Is this a misuse of c() and NA or a bug?  It runs OK in Splus 3.4.

Observed on R 1.0.1 on both linux (compiled on RedHat 6.2) and win95 
(rw1001).

#---------------------------------------------------------------------
a_rep(3+4i,4)

for (i in 1:1000){

   b_c(a,NA,a)                     # b is wrong
   # b_c(a,as.complex(NA),a)         # b is ok
  
   cat(b,i,"\n")
   x_max(c(1,Mod(b[5])),na.rm=T)
   if (x>2) stop()
}
#---------------------------------------------------------------------

Thanks for R; this is my first surprise for many months.

----------------------------------------------------------------------------
John Peters
CSIRO National Measurement Laboratory
PO Box 218                                Phone:    +61 2 9413 7503
Lindfield NSW 2070                        Fax:      +61 2 9413 7202
Australia                                 Internet: John.Peters at tip.CSIRO.AU
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On Mon, May 08, 2000 at 10:22:11AM +1000, John Peters
wrote:
> 
> I struck a problem concatenating two complex vectors with an NA for 
> plotting purposes.  It seems that NA is not automatically coerced to mode 
> complex. In the complex vector "b" below, an NA appears after
half the
> vector, and a zero appears where the NA should be:
> 
> 3+4i 3+4i  NA 3+4i 0+0i 3+4i 3+4i 3+4i 3+4i 285
> 
> This zero seems to coming from free space, as, after running this example 
> a few times, the zero gets replaced by some sort of erratic garbage: 
> 
> 3+4i 3+4i  NA 3+4i 2.466318e+179+6.800902e+199i 3+4i 3+4i 3+4i 3+4i 292 
> 
> Is this a misuse of c() and NA or a bug?  It runs OK in Splus 3.4.
> 
> Observed on R 1.0.1 on both linux (compiled on RedHat 6.2) and win95 
> (rw1001).
> 
> #---------------------------------------------------------------------
> a_rep(3+4i,4)
> 
> for (i in 1:1000){
> 
>    b_c(a,NA,a)                     # b is wrong
>    # b_c(a,as.complex(NA),a)         # b is ok
>   
>    cat(b,i,"\n")
>    x_max(c(1,Mod(b[5])),na.rm=T)
>    if (x>2) stop()
> }
> #---------------------------------------------------------------------
> 
> Thanks for R; this is my first surprise for many months.
Thanks for the bug report!  Access to cut-and-paste makes it all too
easy to avoid thinking about what you are doing.

I am committing a fix to the development tree, but if it is an urgent
problem for you, please replace the "default" case in the function
"ComplexAnswer" in src/main/bind.c with the following:

    default:
        n = LENGTH(x);
        for (i = 0; i < n; i++) {
            xi = INTEGER(x)[i];
            if (xi == NA_INTEGER) {
                COMPLEX(ans_ptr)[ans_length].r = NA_REAL;
                COMPLEX(ans_ptr)[ans_length].i = NA_REAL;
            }
            else {
                COMPLEX(ans_ptr)[ans_length].r = xi;
                COMPLEX(ans_ptr)[ans_length].i = 0.0;
            }
            ans_length++;
        }
        break;

Ross
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