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[Rcpp-devel] Bug report: need to wrap return of sugar functions

8 messages · Darren Cook, Wray, Christopher, Dirk Eddelbuettel

Darren Cook
# 
(Hello, my first post; I discovered Rcpp and inline a few weeks ago, and
I think it is a brilliant idea!)
(Rcpp 0.9.6, R 2.13.1)

I've been having trouble getting the sugar functions to work. I have
more minimal examples than the below, but as this is the one from
Rcpp-sugar.pdf I thought it most convincing:

  library('inline')
  src3='
  using namespace Rcpp;
  NumericVector x(x_),y(y_);
  return ifelse( x<y, x*x, -(y*y) );
  '
  x=c(1:12)
  y=c(4:15)
  fun=cxxfunction(signature(x_="integer",y_="integer"),
    src3, plugin="Rcpp")

[1] shows the error message.

If I change the last line to this, then it works:
  return wrap( ifelse( x<y, x*x, -(y*y) ) );


I have another, possibly related, problem:

  library('inline')
  x=matrix(1:12,4,3);
  print(ifelse(x<5,x*x,x))
  src2='
  using namespace Rcpp;
  NumericMatrix x(x_);
  return wrap(ifelse(x<5,x*x,x));
  '
  fun=cxxfunction(signature(x_ ="integer"),src2,plugin="Rcpp")
  print(fun(x))

Again I need to use wrap() to get past the compiler error, but instead
of returning a matrix (as R's ifelse does), rcpp-sugar returns a vector.
I.e. my program output is:

     [,1] [,2] [,3]
[1,]    1    5    9
[2,]    4    6   10
[3,]    9    7   11
[4,]   16    8   12

 [1]  1  4  9 16  5  6  7  8  9 10 11 12

I've tried both these, but neither compiles:
  return wrap<NumericMatrix>(ifelse(x<5,x*x,x));

  NumericMatrix ret=ifelse(x<5,x*x,x);return ret;

([2] shows the compiler error.)

Thanks,

Darren

[1]:
file6be0c047.cpp: In function ?SEXPREC* file6be0c047(SEXPREC*, SEXPREC*)?:
file6be0c047.cpp:33: error: cannot convert ?Rcpp::sugar::IfElse<14,
true, Rcpp::sugar::Comparator<14, Rcpp::sugar::less<14>, true,
Rcpp::Vector<14>, true, Rcpp::Vector<14> >, true,
Rcpp::sugar::Times_Vector_Vector<14, true, Rcpp::Vector<14>, true,
Rcpp::Vector<14> >, true, Rcpp::sugar::UnaryMinus_Vector<14, true,
Rcpp::sugar::Times_Vector_Vector<14, true, Rcpp::Vector<14>, true,
Rcpp::Vector<14> > > >? to ?SEXPREC*? in return
make: *** [file6be0c047.o] Error 1

ERROR(s) during compilation: source code errors or compiler
configuration errors!



[2]
file1adf689.cpp:34: error: conversion from ?Rcpp::sugar::IfElse<14,
true, Rcpp::sugar::Comparator_With_One_Value<14, Rcpp::sugar::less<14>,
true, Rcpp::Vector<14> >, true, Rcpp::sugar::Times_Vector_Vector<14,
true, Rcpp::Vector<14>, true, Rcpp::Vector<14> >, true, Rcpp::Vector<14>

  
    

      
      
    

  


  


    

    

      
      

        


  

        

      Dirk Eddelbuettel
    

    

      
      #
    

  


  

      
On 15 August 2011 at 11:37, Darren Cook wrote:

        
| (Hello, my first post; I discovered Rcpp and inline a few weeks ago, and
| I think it is a brilliant idea!)
| (Rcpp 0.9.6, R 2.13.1)
| 
| I've been having trouble getting the sugar functions to work. I have
| more minimal examples than the below, but as this is the one from
| Rcpp-sugar.pdf I thought it most convincing:
| 
|   library('inline')
|   src3='
|   using namespace Rcpp;
|   NumericVector x(x_),y(y_);
|   return ifelse( x<y, x*x, -(y*y) );
|   '
|   x=c(1:12)
|   y=c(4:15)
|   fun=cxxfunction(signature(x_="integer",y_="integer"),
|     src3, plugin="Rcpp")
| 
| [1] shows the error message.
| 
| If I change the last line to this, then it works:
|   return wrap( ifelse( x<y, x*x, -(y*y) ) );
| 
| 
| I have another, possibly related, problem:
| 
|   library('inline')
|   x=matrix(1:12,4,3);
|   print(ifelse(x<5,x*x,x))
|   src2='
|   using namespace Rcpp;
|   NumericMatrix x(x_);
|   return wrap(ifelse(x<5,x*x,x));
|   '
|   fun=cxxfunction(signature(x_ ="integer"),src2,plugin="Rcpp")
|   print(fun(x))

No bug.

We never said that you could get by an _implicit_ wrap everywhere. Sometimes
you do need an explicit wrap. This is just one of these situations. Our
examples and unit tests are full of explicit wraps.

| Again I need to use wrap() to get past the compiler error, but instead
| of returning a matrix (as R's ifelse does), rcpp-sugar returns a vector.
| I.e. my program output is:
| 
|      [,1] [,2] [,3]
| [1,]    1    5    9
| [2,]    4    6   10
| [3,]    9    7   11
| [4,]   16    8   12
| 
|  [1]  1  4  9 16  5  6  7  8  9 10 11 12
| 
| I've tried both these, but neither compiles:
|   return wrap<NumericMatrix>(ifelse(x<5,x*x,x));
| 
|   NumericMatrix ret=ifelse(x<5,x*x,x);return ret;
| 
| ([2] shows the compiler error.)

Well, then you may have to assign to a vector first and then set a dimension
argument explicitly.  *Matrix types are pretty close to *Vector types and the
template system does not seem to see a difference.  Maybe Romain can come up
with a clever idea.

Dirk
 
| Thanks,
| 
| Darren
| 
| [1]:
| file6be0c047.cpp: In function ?SEXPREC* file6be0c047(SEXPREC*, SEXPREC*)?:
| file6be0c047.cpp:33: error: cannot convert ?Rcpp::sugar::IfElse<14,
| true, Rcpp::sugar::Comparator<14, Rcpp::sugar::less<14>, true,
| Rcpp::Vector<14>, true, Rcpp::Vector<14> >, true,
| Rcpp::sugar::Times_Vector_Vector<14, true, Rcpp::Vector<14>, true,
| Rcpp::Vector<14> >, true, Rcpp::sugar::UnaryMinus_Vector<14, true,
| Rcpp::sugar::Times_Vector_Vector<14, true, Rcpp::Vector<14>, true,
| Rcpp::Vector<14> > > >? to ?SEXPREC*? in return
| make: *** [file6be0c047.o] Error 1
| 
| ERROR(s) during compilation: source code errors or compiler
| configuration errors!
| 
| 
| 
| [2]
| file1adf689.cpp:34: error: conversion from ?Rcpp::sugar::IfElse<14,
| true, Rcpp::sugar::Comparator_With_One_Value<14, Rcpp::sugar::less<14>,
| true, Rcpp::Vector<14> >, true, Rcpp::sugar::Times_Vector_Vector<14,
| true, Rcpp::Vector<14>, true, Rcpp::Vector<14> >, true, Rcpp::Vector<14>
| >? to non-scalar type ?Rcpp::NumericMatrix? requested
| 
| 
| -- 
| Darren Cook, Software Researcher/Developer
| 
| http://dcook.org/work/ (About me and my work)
| http://dcook.org/blogs.html (My blogs and articles)
| _______________________________________________
| Rcpp-devel mailing list
| Rcpp-devel at lists.r-forge.r-project.org
| https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/rcpp-devel

  
    

      
      
    

  


  


      

    

    

      
      

        


  

        

      Darren Cook
    

    

      
      #
    

  


  

          

      
      
      
    

        
Thanks for the reply.
In that case I'm reporting a bug in the documentation :-)

Darren

  
    

      
      
    

  


  


      

    

    

      
      

        


  

        

      Dirk Eddelbuettel
    

    

      
      #
    

  


  

      
On 15 August 2011 at 22:11, Darren Cook wrote:

        
| > | more minimal examples than the below, but as this is the one from
| > | Rcpp-sugar.pdf I thought it most convincing:
| > | ...
| > No bug.
| > 
| > We never said that you could get by an _implicit_ wrap everywhere. Sometimes
| > you do need an explicit wrap. This is just one of these situations.
| 
| Thanks for the reply.
| In that case I'm reporting a bug in the documentation :-)

Sigh.

_What_ file? _What_ paragraph? _What_ is your suggested fix?

Dirk

  
    

      
      
    

  


  


      

    

    

      
      

        


  

        

      Wray, Christopher
    

    

      
      #
    

  


  

      
=============
   x=matrix(1:12,4,3);
   print(ifelse(x<5,x*x,x))

src2='
using namespace Rcpp;
NumericMatrix x(x_);
NumericVector y=ifelse(x<5,x*x,x);
y.attr("dim")=Dimension(x.nrow(),x.ncol());
return y;
'
fun=cxxfunction(signature(x_ ="integer"),src2,plugin="Rcpp")
print(fun(x))

===========
does this do it for you

        

      
      
    

  
  


  


      

    

    

      
      

        


  

        

      Dirk Eddelbuettel
    

    

      
      #
    

  


  

      
On 15 August 2011 at 08:36, Dirk Eddelbuettel wrote:

        
|

        
| On 15 August 2011 at 22:11, Darren Cook wrote:

        
| | > | more minimal examples than the below, but as this is the one from
| | > | Rcpp-sugar.pdf I thought it most convincing:
| | > | ...
| | > No bug.
| | > 
| | > We never said that you could get by an _implicit_ wrap everywhere. Sometimes
| | > you do need an explicit wrap. This is just one of these situations.
| | 
| | Thanks for the reply.
| | In that case I'm reporting a bug in the documentation :-)
| 
| Sigh.
| 
| _What_ file? _What_ paragraph? _What_ is your suggested fix?

To close this, Darren filled me in off-list and there was indeed a
Rcpp::wrap() call missing in an early example in the Rcpp-sugar vignette.

Now corrected, with a tip-of-the-hat to Darren.

Dirk

  
    

      
      
    

  


  


      

    

    

      
      

        


  

        

      Darren Cook
    

    

      
      #
    

  


  

      
On 2011-08-16 08:34, Wray, Christopher wrote:

            

      
      
      
    

        
Hello Christopher,
Thanks for the suggestion. It works perfectly (I suspect some template
magic could make this assignment automatic).

Darren

  
    

      
      
    

  


  


      

    

    

      
      

        


  

        

      Dirk Eddelbuettel
    

    

      
      #
    

  


  

      
On 16 August 2011 at 11:11, Darren Cook wrote:

        
| On 2011-08-16 08:34, Wray, Christopher wrote:

        
| > =============
| >    x=matrix(1:12,4,3);
| >    print(ifelse(x<5,x*x,x))
| > 
| > src2='
| > using namespace Rcpp;
| > NumericMatrix x(x_);
| > NumericVector y=ifelse(x<5,x*x,x);
| > y.attr("dim")=Dimension(x.nrow(),x.ncol());
| > return y;
| > '
| > fun=cxxfunction(signature(x_ ="integer"),src2,plugin="Rcpp")
| > print(fun(x))
| > 
| > ===========
| > does this do it for you
| 
| Hello Christopher,
| Thanks for the suggestion. It works perfectly (I suspect some template
| magic could make this assignment automatic).

Patches are always welcome :-) We can offer rewards as glorious as an entry
in the inst/THANKS file installed with Rcpp.

Dirk