geoff.cpp

#include <iostream>
#include <opencv2/opencv.hpp>

int main(void) {
  using namespace cv;

  Mat m(8192, 81, CV_32FC1);
  randu(m, Scalar(0), Scalar(1));
  int64 tic = getTickCount();
  Mat m2 = m * m.t();
  std::cout << (getTickCount() - tic) / getTickFrequency() << std::endl;
}

geoff.m

m = rand(8192, 81); 
tic;
result = m * m';
toc;

geoff.py

import numpy as np
from timeit import default_timer as timer

m = np.random.rand(8192, 81)
tic = timer()
result = np.dot(m, m.T)
print (timer() - tic)

Makefile

.PHONY: timeit

timeit: geoff.py geoff.m geoff
	@./geoff
	@python geoff.py
	@octave geoff.m

# 9.02029
# 2.83632302284
# 2.10921

geoff: geoff.cpp Makefile
	g++ -O2 $< -lopencv_core -o $@