Index out of bounds error when using Rcpp function with mapply

Question

I get "Error: index out of bounds" when I am using mapply with a Rcpp function:

R:

mapply(fun, x = totPrimas, y = factorProjec, w = totCurvadf)

x, y and z are data frames with the same dimensions.

Rcpp:

#include <Rcpp.h>
using namespace Rcpp;

// [[Rcpp::export]]
NumericVector fun(const NumericVector x, const NumericVector y, const NumericVector w ) {
  NumericVector z(x.size()); 
  z(0) = x(0) * y(0);
  NumericVector c(x.size()); 
  c(0) = x(0) * w(0);
  for(int i = 1; i < x.size(); i++) {
    c(i) = (c(i-1) + x(i)) * w(i); 
    z(i) = c(i) * y(i);
  }
  return z;
}

Is something wrong in the code? Thanks alot.

Answer 1

As you've noted, the problem was that totCurvadf was a matrix. The reason this was an issue is that aMatrix[1] will return a vector of length 1, whereas aDataFrame[1] will return the first column of the data.frame as a vector of length equal to nrow(aDataFrame).

If you did want to do this with matrices (or a mixture of data frames and matrices, you could do:

lapply(1:nrow(totPrimas), function(i) fun(x = totPrimas[, i], y = factorProjec[, i], w = totCurvadf[, i]))