7.61 bug in evalc by functions with indexed names in Maple V.4 to Maple 6 (29.7.97)

7.61.1 Eike Elbraechter

I believe, there is a bug in 'evalc'. The routine don’t work, if the expression contains unevaluated function calls with indexed names.

> restart; 
  kernelopts(version); 
  interface (version); 
  interface (patchlevel); 
  libname; 
 
  Maple V, Release 4, IBM RISC UNIX, Nov 20, 1996, RS2-54CD-328813-7 
  Maple Worksheet Interface, Release 4, IBM RISC UNIX, Nov 25, 1996 
                                  2 
           /usr/local/maple4/update, /usr/local/maple4/lib 
 
> `evalc/b` := proc()      # to test the user interface of evalc 
      RETURN( u(t)+I*v(t) ); 
  end: 
 
> for w in [ I*( a      +I*b       ) 
           , I*( a(t)   +I*b(t)    ) 
           , I*( a[1]   +I*b[1]    ) 
           , I*( a[1](t)+I*b[1](t) ) 
           ] 
  do 
    'evalc'(w) = evalc( w); 
  od; 
 
evalc(I*(a+I*b))             = I*a-b 
evalc(I*(a(t)+I*b(t)))       = -u(t)+I*(a(t)-v(t)) 
evalc(I*(a[1]+I*b[1]))       = I*a[1]-b[1] 
evalc(I*(a[1](t)+I*b[1](t))) = I*(a[1](t)+I*b[1](t))
 

The last expression with an indexed name of an unevaluated function call is not expanded.

If the source of the routine ‘evalc/evalc‘ near the line 13 (get with list of the debugger) is changed from

     elif type(z,'function') then 
..... to 
 
    elif type(z, 'function') then 
        g := op(0, z); 
        if type(g, name ) then 
            f := `if`( type(g, 'indexed'), op(0,g), g ); 
            f := `evalc/`.f; 
            if not type(f, 'procedure') then traperror(readlib(f)) fi; 
            if type(f, 'procedure') then w := (`evalc/`.g)(op(z)) 
            else 
          ......
 

than the result is full evaluated:

> for w in [ I*( a      +I*b       ) 
           , I*( a(t)   +I*b(t)    ) 
           , I*( a[1]   +I*b[1]    ) 
           , I*( a[1](t)+I*b[1](t) ) 
           ] 
  do 
    'evalc'(w) = evalc( w); 
  od; 
 
evalc(I*(a+I*b))             = I*a-b 
evalc(I*(a(t)+I*b(t)))       = -u(t)+I*(a(t)-v(t)) 
evalc(I*(a[1]+I*b[1]))       = I*a[1]-b[1] 
evalc(I*(a[1](t)+I*b[1](t))) = -u(t)+I*(a[1](t)-v(t))
 

but I am not sure, that this is a correct correction.

It is corrected with Maple 7. (U. Klein)