#! /usr/bin/env python # def r8vec_variance ( n, a ): #*****************************************************************************80 # ## R8VEC_VARIANCE returns the variance of an R8VEC. # # Discussion: # # An R8VEC is a vector of R8's. # # Licensing: # # This code is distributed under the GNU LGPL license. # # Modified: # # 03 March 2015 # # Author: # # John Burkardt # # Parameters: # # Input, integer N, the number of entries in the vector. # # Input, real A(N), the vector. # # Output, real VALUE, the variance of the vector. # import numpy as np # # DDOF = 1 requests normalization by N-1 rather than N. # value = np.var ( a, ddof = 1 ) return value def r8vec_variance_test ( ): #*****************************************************************************80 # ## R8VEC_VARIANCE_TEST tests R8VEC_VARIANCE. # # Licensing: # # This code is distributed under the GNU LGPL license. # # Modified: # # 02 March 2015 # # Author: # # John Burkardt # import platform from r8vec_print import r8vec_print from r8vec_uniform_ab import r8vec_uniform_ab print ( '' ) print ( 'R8VEC_VARIANCE_TEST' ) print ( ' Python version: %s' % ( platform.python_version ( ) ) ) print ( ' R8VEC_VARIANCE computes the variance of an R8VEC.' ) n = 10 r8_lo = - 5.0 r8_hi = + 5.0 seed = 123456789 a, seed = r8vec_uniform_ab ( n, r8_lo, r8_hi, seed ) r8vec_print ( n, a, ' Input vector:' ) value = r8vec_variance ( n, a ) print ( '' ) print ( ' Value = %g' % ( value ) ) # # Terminate. # print ( '' ) print ( 'R8VEC_VARIANCE_TEST:' ) print ( ' Normal end of execution.' ) return if ( __name__ == '__main__' ): from timestamp import timestamp timestamp ( ) r8vec_variance_test ( ) timestamp ( )