Add inductive and resistive elements

collective_effects/__init__.py

@@ -7,7 +7,7 @@ Created on Tue Jan 14 12:25:30 2020
 
 from mbtrack2.collective_effects.instabilities import mbi_threshold, cbi_threshold
 from mbtrack2.collective_effects.resistive_wall import skin_depth, CircularResistiveWall
-from mbtrack2.collective_effects.resonator import Resonator
+from mbtrack2.collective_effects.resonator import Resonator, PureInductive, PureResistive
 from mbtrack2.collective_effects.tapers import StupakovRectangularTaper, StupakovCircularTaper
 from mbtrack2.collective_effects.wakefield import ComplexData, Impedance, WakeFunction, WakeField
 from mbtrack2.collective_effects.utilities import read_CST, read_IW2D, spectral_density

collective_effects/resonator.py

@@ -12,7 +12,7 @@ from mbtrack2.collective_effects.wakefield import (WakeField, Impedance,
                                                    WakeFunction)
 
 class Resonator(WakeField):
-    def __init__(self, Rs, fr, Q, plane, n_wake=1e4, n_imp=1e4, imp_freq_lim=50e9):
+    def __init__(self, Rs, fr, Q, plane, n_wake=1e6, n_imp=1e6, imp_freq_lim=100e9):
         """
         Resonator model WakeField element which computes the impedance and the 
         wake function in both longitudinal and transverse case.
@@ -28,11 +28,11 @@ class Resonator(WakeField):
         plane : str
             Plane on which the resonator is used: "long", "x" or "y".
         n_wake : int or float, optional
-            Number of points used in the wake function. The default is 1e4.
+            Number of points used in the wake function.
         n_imp : int or float, optional
-            Number of points used in the impedance. The default is 1e4.
+            Number of points used in the impedance.
         imp_freq_lim : float, optional
-            Maximum frequency used in the impedance. The default is 50e9.
+            Maximum frequency used in the impedance.
             
         References
         ----------
@@ -118,3 +118,75 @@ class Resonator(WakeField):
             return (self.wr * self.Rs / self.Q_p * 
                     np.exp(-1 * t * self.wr / 2 / self.Q_p) *
                     np.sinh(self.wr_p * t) )
+    
+class PureInductive(WakeField):
+    """
+    Pure inductive Wakefield element which computes associated longitudinal 
+    impedance and wake function.
+    
+    Parameters
+    ----------
+    L : float
+        Inductance value in [Ohm/Hz].
+    n_wake : int or float, optional
+        Number of points used in the wake function.
+    n_imp : int or float, optional
+        Number of points used in the impedance.
+    imp_freq_lim : float, optional
+        Maximum frequency used in the impedance. 
+    nout, trim : see Impedance.to_wakefunction
+    """
+    def __init__(self, L, n_wake=1e6, n_imp=1e6, imp_freq_lim=1e11, nout=None,
+                 trim=False):
+        self.L = L
+        self.n_wake = int(n_wake)
+        self.n_imp = int(n_imp)
+        self.imp_freq_lim = imp_freq_lim
+        
+        freq = np.linspace(start=1, stop=self.imp_freq_lim, num=self.n_imp)
+        imp = Impedance(variable=freq, 
+                        function=self.long_impedance(freq),
+                        impedance_type="long")
+        super().append_to_model(imp)
+        
+        wf = imp.to_wakefunction(nout=nout, trim=trim)
+        super().append_to_model(wf)
+        
+    def long_impedance(self, f):
+        return 1j*self.L*f
+    
+class PureResistive(WakeField):
+    """
+    Pure resistive Wakefield element which computes associated longitudinal 
+    impedance and wake function.
+    
+    Parameters
+    ----------
+    R : float
+        Resistance value in [Ohm].
+    n_wake : int or float, optional
+        Number of points used in the wake function.
+    n_imp : int or float, optional
+        Number of points used in the impedance.
+    imp_freq_lim : float, optional
+        Maximum frequency used in the impedance. 
+    nout, trim : see Impedance.to_wakefunction
+    """
+    def __init__(self, R, n_wake=1e6, n_imp=1e6, imp_freq_lim=1e11, nout=None,
+                 trim=False):
+        self.R = R
+        self.n_wake = int(n_wake)
+        self.n_imp = int(n_imp)
+        self.imp_freq_lim = imp_freq_lim
+        
+        freq = np.linspace(start=1, stop=self.imp_freq_lim, num=self.n_imp)
+        imp = Impedance(variable=freq, 
+                        function=self.long_impedance(freq),
+                        impedance_type="long")
+        super().append_to_model(imp)
+        
+        wf = imp.to_wakefunction(nout=nout, trim=trim)
+        super().append_to_model(wf)
+        
+    def long_impedance(self, f):
+        return self.R
\ No newline at end of file

collective_effects/wakefield.py

@@ -569,13 +569,14 @@ class Impedance(ComplexData):
     def to_wakefunction(self, nout=None, trim=False):
         """
         Return a WakeFunction object from the impedance data.
+        The impedance data is assumed to be sampled equally.
     
         Parameters
         ----------
-        nout : int, optional
+        nout : int or float, optional
             Length of the transformed axis of the output. If None, it is taken
             to be 2*(n-1) where n is the length of the input. If nout > n, the
-            input is padded with zeros. If nout < n, the inpu it cropped.
+            input is padded with zeros. If nout < n, the input it cropped.
             Note that, for any nout value, nout//2+1 input points are required.
         trim : bool or float, optional
             If True, the pseudo wake function is trimmed at time=0 and is forced 
@@ -597,6 +598,8 @@ class Impedance(ComplexData):
         
         if nout is None:
             nout = len(Z)
+        else:
+            nout = int(nout)
             
         time_array = sc.fft.fftfreq(nout, sampling)
         Wlong_raw = sc.fft.irfft(np.array(Z), n=nout, axis=0) * nout * fs