.. _gaussian_random_field::

Generate a realization of a gaussian random field with known power spectrum
===========================================================================

::

	"""
	Generate gaussian random fields with a known power spectrum
	
	"""
	
	import numpy as np
	import matplotlib.pyplot as plt
	
	from astropy.units import deg
	
	from lenstools import GaussianNoiseGenerator
	
	#Set map side angle, and number of pixels on a side
	num_pixel_side = 512
	side_angle = 3.41 * deg
	
	#Read the power spectrum (l,Pl) from an external file, and load it in numpy array format (the generator interpolates the power spectrum between bins)
	l,Pl = np.loadtxt("Data/ee4e-7.txt",unpack=True)
	
	#Instantiate the gaussian noise generator
	gen = GaussianNoiseGenerator(shape=(num_pixel_side,num_pixel_side),side_angle=side_angle,label="convergence")
	
	#Generate one random realization
	gaussian_map = gen.fromConvPower(np.array([l,Pl]),seed=1,kind="linear",bounds_error=False,fill_value=0.0)
	
	#gaussian_map is a ConvergenceMap instance
	gaussian_map.visualize()
	gaussian_map.savefig("example_map.png")

This is the result 

.. figure:: ../../../examples/example_map.png