benchmarking

I have followed a number of questions here that asks about how to convert character vectors to datetime classes. I often see 2 methods, the strptime and the as.POSIXct/as.POSIXlt methods. I looked at the 2 functions but am unclear what the difference is. strptime function (x, format, tz = "") { y <- .Internal(strptime(as.character(x), format, tz)) names(y$year) <- names(x) y } <bytecode: 0x045fcea8> <environment: namespace:base> as.POSIXct function (x, tz = "", ...) UseMethod("as.POSIXct") <bytecode: 0x069efeb8> <environment: namespace:base> as.POSIXlt function (x, tz = "", ...) UseMethod("as

I wanted to find which is faster: struct vs array. So I wrote a GO code in which I write 4 int values (1,2,3 and 4) to the members of a structure and then to an array of length 4. I tried to find the time it takes to write. Case1: First, I write values to a structure and then to an array. Here I found array to be faster than structure. package main import ( "fmt" "time" ) type abc struct { a, b, c, d int } func main() { var obj abc t1 := time.Now() obj.a = 1 obj.b = 2 obj.c = 3 obj.d = 4 t2 := time.Since(t1) fmt.Println("Struct access time: : ", t2) a := make([]int, 4) t3 := time.Now() a[0] =

I have written a code that randomly generates two matrices from dimensions 2x2 up to 50x50. I am then recording the time it takes for each matrix multiplication from dimensions 2 up to 50. I record this time 100 times to get a good average for each case 2 -50. The program first starts off by multiplying the matrices sequentially and records the average execution time in a csv file. It then moves on to parallel matrix multiplication using pthreads and records the average execution times in a separate csv file. My issue is that the average execution time for the sequential multiplication is a

I'm trying to create a benchmark test with java. Currently I have the following simple method: public static long runTest(int times){ long start = System.nanoTime(); String str = "str"; for(int i=0; i<times; i++){ str = "str"+i; } return System.nanoTime()-start; } I'm currently having this loop multiple times within another loop that is happening multiple times and getting the min/max/avg time it takes to run this method through. Then I am starting some activity on another thread and testing again. Basically I am just wanting to get consistent results... It seems pretty consistent if I have

I am trying to encrypt and decrypt data using AES/GCM/NoPadding. I installed the JCE Unlimited Strength Policy Files and ran the (simple minded) benchmark below. I've done the same using OpenSSL and was able to achieve more than 1 GB/s encryption and decryption on my PC. With the benchmark below I'm only able to get 3 MB/s encryption and decryption using Java 8 on the same PC. Any idea what I am doing wrong? public static void main(String[] args) throws Exception { final byte[] data = new byte[64 * 1024]; final byte[] encrypted = new byte[64 * 1024]; final byte[] key = new byte[32]; final byte