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proxtoolbox/ProxOperators/P_S_real.py

+import numpy as np
+from proxoperators import ProxOperator
+"""
+#original matlab comment
+%                      P_S_real.m
+%             written on May 23, 2002 by 
+%                   Russell Luke
+%   Inst. Fuer Numerische und Angewandte Mathematik
+%                Universitaet Gottingen
+%
+% DESCRIPTION:  Projection subroutine for projecting onto
+%               support constraints
+%
+% INPUT:        input = data structure with .supp_ampl a vector of indeces of the nonzero elements of the array.
+%
+%               u = array to be projected
+%
+% OUTPUT:       p_S    = the projection 
+%               
+% USAGE: p_S = P_S(input,u)
+%
+% Nonstandard Matlab function calls:  
+"""
+class P_S_real(ProxOperator):
+
+	def __init__(self,config):
+		"""
+		Initialization
+        
+        Parameters
+        ----------
+        config : dict - Dictionary containing the problem configuration. It must contain the following mapping:
+		'support_idx' : array_like
+		"""
+		self.support_idx = config['support_idx']
+
+	def work(self,u):
+		"""
+		Parameters
+        ----------
+        u : array_like - Input
+        
+        Returns
+        -------
+		p_S : array_like
+		"""
+		support_idx = self.support_idx
+		p_S = np.zeros(u.shape, dtype=u.dtype)
+		p_S[support_idx] = np.real(u[support_idx])
+		return p_S
+
+
+
+