Rcpp Matrix Multiplication Function
Subsetting v u. You could then define an R function to dispatch the appropriate C function.
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However even if you set a value to attribute dim of a Vector object the type of the object remains a Vector type in Rcpp code.
Rcpp matrix multiplication function. I am wondering if there is any simple way to help me avoid the following loop to conduct this calculation. RcppNumericVector colSums pBigMat-ncol. Writing this multiplication in Rcpp is no more than two loops.
However to answer your question below is a possible Rcpp code to perform a matrix multiplication. Rep53 NumericVector v NumericVector. Using namespace Rcpp.
Depending on the computer maybe higher dimensions are required for the function to make a difference. J result j i 1 return result systemtime print sum_by_row a 1 1248361320. Forintk 0.
M1triangularView matAtranspose matA. Int n bMPtr- nrow. Doubleip 0.
For size_t i 0. Finally lets look at RcppArmadillo. A A - 1.
Multiplying part of a NumericMatrix row by a NumericVector. According to the documentation you can evaluate the lower triangle of a matrix with. I am wondering is there a way of calculating matrix multiplication using NumericMatrix and NumericVector class.
Row and Column act as vectors r 0 c 0 0. A matrixc1234 nrow 2 A. I rm1 m1i_.
A. Fun. Create Named row rvec Named col cvec R x.
MaxX dim0 Extremum value of each column of X row if dim1 transX or Xt Return transpose of X R cholX Cholesky decomposition of X such that RT R X invX or Xi Returns the inverse of square matrix X. Armadillo has a number of object types including mat colvec and rowvec. There are faster than Rs function for large matrices.
Rcppexport NumericVector prod1 XPtr bMPtr const NumericVector. Here we just use colvec to represent a column vector of prices. Row r x.
NormX p Compute the p-norm of matrix or vector X rankX Compute the rank of matrix X minX dim0. Code. NumericVector cvec c.
I colSums i stdaccumulate ma i ma ipBigMat-nrow 00. Or in your case. NumericVector v 5 3.
Change of v1 will result in change of v2 NumericVector v1 clone v2. By default in Armadillo represents matrix multiplication and is used for element wise multiplication. Only the referenced triangular part is evaluated.
Matrix multiplication element-wise In R is simple. It is widely used in areas such as network theory transformation of coordinates and many more uses nowadays. They can also be assigned to vectors NumericVector rvec r.
MatrixAccessor ma pBigMat. Where it says Writing to a specific triangular part. Thus if you want to convert it to Matrix type in Rcpp you need to use as function.
A matrix in R can be created using matrix function and this function takes input vector nrow ncol byrow dimnames as arguments. Matrix multiplication is the most useful matrix operation. Create the vector well store the column sums in.
Iterator j row. LibraryRcpp cppFunctionNumericMatrix mmultconst NumericMatrix. SolveA B solveAB conceptually similar to invAB but more efficient.
Simple matrix to matrix function using rcpp. A A 1. Sp_mat.
Create 1 2 3. The functions performs matrix multiplication croos product and transpose cross product. K ip xk yk returnip Vectors require 1 loop.
ASPC Linear Algebra with RcppArmadillo Day 4 AM 4 68. A matrix0 k k A zeros kk matrix1 k k A ones kk A B. Set number of rows and columns to attribute dim vattr dim Dimension 2 2.
A matrix the result of the matrix multiplication. Converting to Rcpp Matrix type NumericMatrix m as v. NumericVector v1 v2.
Rep03 NumericVector v 1 2 3. Return variance In R. The function runs in parallel in C.
Where u is a LogicalVector Use clone function when you dont want your vector or matrix value to be changed. K K. M1triangularView m2 m3.
NumericVector v 3. Matrix operations would require 2 loops. Matrix19 33matrix19 33 1 2 3 1 1 16 49 2 4 25 64 3 9 36 81 In Rcpp.
Square return sumn-bias. Building off of Dirks comment here are a few cases that demonstrate the Armadillo librarys matrix multiplication via the overloaded operator. RcppdependsRcppEigen bigmemory BH include include Florian Privé Rcpp enthusiast.
I pBigMat-ncol. Column c x. Rcppexport RObject ex_Matrix_rowcol NumericMatrix x int ir int ic NumericMatrix.
Rcppexport doublevarRcppNumericVector xboolbias true Calculate the mean using C function doublemeanmuRcppx. Include using namespace Rcpp. RcppdependsRcppArmadillo include Rcppexport double sum_by_row const arma.
Rcppexport doubleinner1 NumericVector x NumericVector y intK xlength. For size_t i 0.
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