Also, after your comments, it just hit me why not write the entire code in
pure C++? Would that be worthwhile?
On Thu, Jul 27, 2017 at 10:59 AM, Sharat <schmoo...@gmail.com> wrote:
> Thanks Serguei for clearing up the data structures. I did test the
> function in R but when I was printing out the results, rather than
> returning a vector; sorry about that. Will be much more careful.
>
> On Thu, Jul 27, 2017 at 9:47 AM, Serguei Sokol <serguei.so...@gmail.com>
> wrote:
>
>> Hi Sharat,
>>
>> First, few preliminary remarks before answering your question.
>> 1. Just like every one asking for assistance, your should provide a
>> minimal reproducible example.
>> 2. Before asking about Rcpp issue, it would be reasonable if you test
>> your comps() function in R,
>> to be sure that the problem is not in comps() itself (and yes, there is a
>> problem in comps(), cf. hereafter)
>> 3. It is counter-intelligent to use Rcpp just for calling an R function.
>> Sometimes such calling is
>> unavoidable but doing _only_ this is a waste of time. Simply call your
>> function directly from R.
>> Main interest of Rcpp is to easily interface functions written in C++
>> (which are usually
>> much faster then their counterparts in R) with R session.
>>
>> Now, about your problem.
>> In fact, your version of comps() returns always NULL which causes the
>> error message.
>> It is because of the line:
>> append(res,paste(prop1,"<-->", prop2))
>> which should be
>> res=append(res,paste(prop1,"<-->", prop2))
>>
>> Furthermore, when corrected and in presence of matches, comps() returns a
>> string vector, not a matrix.
>> So your have to invert your declarations of getGoing() making him return
>> a StringVector and taking
>> as argument a StringMatrix. In shorter writing, it gives:
>>
>> // [[Rcpp::export]]
>> StringVector getGoing(StringMatrix vec){
>> Function f = Environment::global_env()["comps"];
>> return f(vec);
>> }
>>
>> Best,
>> Serguei.
>>
>> Le 27/07/2017 à 15:30, Sharat a écrit :
>>
>>> Hi:
>>>
>>> I'm trying to call a R function (that compares strings) in Rcpp and
>>> return the result to make the comparisons run faster. Am a noob with Rcpp;
>>> so please bear. The input to the R function is a matrix of 2 columns.
>>>
>>> The error is: *Error in getGoing(product) : Not compatible with STRSXP:
>>> [type=NULL]. *
>>>
>>>
>>> Please assist.
>>>
>>> #include<Rcpp.h>
>>> using namespace Rcpp;
>>>
>>> /*** R
>>> comps= function(vec)
>>> {
>>> streets <- vec
>>> cnt <- nrow(streets)
>>> res <- c()
>>> print(paste0("Comparing ", (cnt)," pairs..."))
>>> for (i in 1:cnt)
>>> {
>>> matched <- TRUE
>>> prop1 = streets[i,1]
>>> prop2 = streets[i,2]
>>>
>>> prop1_parts = strsplit(trimws(prop1), ' ')
>>> prop2_parts = strsplit(trimws(prop2), ' ')
>>> prop1_parts_count = length(prop1_parts[[1]])
>>> prop2_parts_count = length(prop2_parts[[1]])
>>> if (prop1_parts_count == prop2_parts_count)
>>> {
>>> for (x in 1:prop1_parts_count)
>>> {
>>> part1 = prop1_parts[[1]][x]
>>> part2 = prop2_parts[[1]][x]
>>> if (part1 == part2) {
>>> matched = matched & TRUE
>>> }
>>> else if (adist(part1, part2, partial = T)==0 |
>>> adist(part2,part1, partial = T)==0){
>>> matched = matched & TRUE
>>> }
>>> else {
>>> matched = matched & FALSE
>>> break
>>> }
>>> }#forloop ends
>>> if(matched){
>>> append(res,paste(prop1,"<-->", prop2))
>>> }
>>> }#if loops ends
>>> }#primary for loops ends
>>> res
>>> }#function ends
>>> */
>>>
>>> // [[Rcpp::export]]
>>> Rcpp::StringMatrix getGoing(Rcpp::StringVector vec){
>>> Rcpp::Environment env = Rcpp::Environment::global_env();
>>> Rcpp::Function f = env["comps"];
>>> Rcpp::StringMatrix result = f(vec);
>>> return result;
>>> }
>>>
>>>
>>>
>>> _______________________________________________
>>> Rcpp-devel mailing list
>>> Rcpp-devel@lists.r-forge.r-project.org
>>> https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/rcpp-devel
>>>
>>>
>>
>
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