fix case no SC points

Author: serfass

qetpy/core/_ibis.py

@@ -526,7 +526,11 @@ def analyze(self, yoff=None, yoff_err=None, xoff=None, xoff_err=None):
             ibias_off = np.zeros_like(int_n)
             ibias_off_err = np.zeros_like(int_n)
             rp = self.rp_guess
+            if rp.ndim == 2:
+                rp = rp[np.newaxis,:,:]
             rp_err = self.rp_err_guess
+            if rp_err.ndim == 2:
+                rp_err = rp_err[np.newaxis,:,:]
             int_point_y = int_n
             int_point_x = np.zeros_like(int_n)