[Rd] Numerical accuracy of matrix multiplication

[Alexis Sarda]

Hello,

while testing the crossprod() function under Linux, I noticed the following:

set.seed(883)
x <- rnorm(100)
x %*% x - sum(x^2) # equal to 1.421085e-14

Is this difference normal? It seems to be rather large for double precision.

Regards,
Alexis.

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