In [3]:

    

5


    

    
Out[3]:




5

In [5]:

    

y <- matrix(c(1,2,3,4,3,4),2,3)


    

In [6]:

    

y


    

    
Out[6]:






	
1
3
3
	
2
4
4

In [14]:

    

x <- c(1:6)


    

In [13]:

    

x


    

    
Out[13]:





	
1
	
2
	
3
	
4
	
5
	
6

In [16]:

    

f <- function(x)
{
  x^3 + x^2 + x + 10
}


    

In [17]:

    

f(x)


    

    
Out[17]:





	
13
	
24
	
49
	
94
	
165
	
268

In [54]:

    

u <- c(4,3,2,1)
u


    

    
Out[54]:





	
4
	
3
	
2
	
1

In [55]:

    

v <- c(1,2,3,4)
v


    

    
Out[55]:





	
1
	
2
	
3
	
4

In [52]:

    

u*v


    

    
Out[52]:





	
4
	
6
	
6
	
4

In [53]:

    

u%*%v


    

    
Out[53]:






	
20

In [38]:

    

?"%*%"


    

    
Out[38]:





matmult {base}
R Documentation

Matrix Multiplication

Description

Multiplies two matrices, if they are conformable.  If one argument is
a vector, it will be promoted to either a row or column matrix to make
the two arguments conformable.  If both are vectors of the same
length, it will return the inner product (as a matrix).



Usage

x %*% y



Arguments


x, y

numeric or complex matrices or vectors.




Details

When a vector is promoted to a matrix, its names are not
promoted to row or column names, unlike as.matrix.

This operator is S4 generic but not S3 generic.  S4 methods need to be
written for a function of two arguments named x and y.



Value

A double or complex matrix product.  Use drop to remove
dimensions which have only one level.



Note

Since R 3.2.0, promotion of a vector to a 1-row or 1-column matrix
happens in even more cases, when one of the two choices allows
x and y to get conformable dimensions.



References

Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988)
The New S Language.
Wadsworth & Brooks/Cole.



See Also

For matrix crossproducts, crossprod() and
tcrossprod() are typically preferable.
matrix, Arithmetic, diag.



Examples

x <- 1:4
(z <- x %*% x)    # scalar ("inner") product (1 x 1 matrix)
drop(z)             # as scalar

y <- diag(x)
z <- matrix(1:12, ncol = 3, nrow = 4)
y %*% z
y %*% x
x %*% z


[Package base version 3.2.4 ]

In [57]:

    

sc <- sparkR.init()
sqlContext <- sparkRSQL.init(sc)


    

    




Error in eval(expr, envir, enclos): could not find function "sparkR.init"






    




Error in eval(expr, envir, enclos): could not find function "sparkRSQL.init"

In [58]:

    

library(SparkR, lib.loc = c(file.path(Sys.getenv("SPARK_HOME"), "R", "lib")))


    

    




Attaching package: 'SparkR'

The following objects are masked from 'package:stats':

    cov, filter, lag, na.omit, predict, sd, var

The following objects are masked from 'package:base':

    colnames, colnames<-, intersect, rank, rbind, sample, subset,
    summary, table, transform

In [ ]: