FIX: syntax warnings with unsupported escape sequences

pmd_beamphysics/fields/analysis.py

@@ -12,7 +12,7 @@
 # Analysis
 
 def accelerating_voltage_and_phase(z, Ez, frequency):
-    """
+    r"""
     Computes the accelerating voltage and phase for a v=c positively charged particle in an accelerating cavity field.
     
         Z = \int Ez * e^{-i k z} dz 
@@ -57,7 +57,7 @@ def track_field_1d(z,
                    debug=False,
                    max_step=None,
                   ):
-    """
+    r"""
     Tracks a particle in a 1d complex electric field Ez, oscillating as Ez * exp(-i omega t)
     
     Uses scipy.integrate.solve_ivp to track the particle. 
@@ -181,7 +181,7 @@ def track_field_1df(Ez_f,
                    max_step=None,
                     method='RK23'
                   ):
-    """
+    r"""
     Similar to track_field_1d, execpt uses a function Ez_f
     
     Tracks a particle in a 1d electric field Ez(z, t)

pmd_beamphysics/labels.py

@@ -122,7 +122,7 @@ def texlabel(key: str):
     if key.startswith('bunching'):
         wavelength = parse_bunching_str(key)
         x, _, prefix = nice_array(wavelength)
-        return f'\mathrm{{bunching~at}}~{x:.1f}~\mathrm{{ {prefix}m }}'
+        return fr'\mathrm{{bunching~at}}~{x:.1f}~\mathrm{{ {prefix}m }}'
 
     return None
 

pmd_beamphysics/particles.py

@@ -678,7 +678,7 @@ def average_current(self):
         return self.charge / dt
 
     def bunching(self, wavelength):
-        """
+        r"""
         Calculate the normalized bunching parameter, which is the magnitude of the 
         complex sum of weighted exponentials at a given point.