replace _np by np (correct for bug)

maoppy/psfmodel.py

@@ -407,21 +407,21 @@ class ParametricPSFfromPSD(ParametricPSF):
         
         self.fixed_k = fixed_k
         self.system = system
-        self.npix = npix # "_" to bypass the _computeXYarray update, that will be made with samp setter
+        self._npix = npix # "_" to bypass the _computeXYarray update, that will be made with samp setter
         self.samp = samp # also init _computeXYarray and _otfDiffraction
-        self.nparam = nparam
+        self._nparam = nparam
         self.bounds = ((-np.inf,)*nparam, (np.inf,)*nparam)
         
         
     @property
     def npix(self):
         """Number of required pixels for arrays"""
-        return self.npix
+        return self._npix
     
     
     @npix.setter
     def npix(self, value):
-        self.npix = value
+        self._npix = value
         self._computeXYarray()
         self._computeOtfDiffraction()
         
@@ -508,7 +508,7 @@ class ParametricPSFfromPSD(ParametricPSF):
         parampsd = np.array(parampsd)
         bdn = np.array(bdn)
         bup = np.array(bup)
-        if len(parampsd)!=self.nparam:
+        if len(parampsd)!=self._nparam:
             raise ValueError('len(parampsd) is different from length of bounds')
         if np.any(parampsd<bdn):
             raise ValueError('Lower bounds are not respected')