Change values flutter speed and mode values when no flutter is found. Merge...

Change values flutter speed and mode values when no flutter is found. Merge solution files into one.

pypk/solution.py

@@ -62,8 +62,8 @@ class Solution:
         """Find the flutter speed and display it
         """
         found = False
-        self.f_speed = np.inf
-        self.f_mode = np.inf
+        self.f_speed = -1.
+        self.f_mode = -1
         for ivel in range(len(self.speed) - 1):
             if (found):
                 break
@@ -82,9 +82,8 @@ class Solution:
         """Write results to disk
         sfx : filename suffix
         """
-        hdr = '{:>8s}, {:>10s}, {:>10s}, {:>10s}'.format('Mach', 'u_f', 'mode', 'AGG(g)')
-        np.savetxt(f'results_{self._name}{sfx}.dat', np.array([self._mach, self.f_speed, self.f_mode, self.damp_agg]).reshape(1,4), fmt='%10.4f', delimiter=', ', header=hdr)
-        hdr = '{:>9s}'.format('u_inf')
+        hdr = 'Mach={:.2f}, u_f={:.2f}, mode={:d}, AGG(g)={:.2f}\n'.format(self._mach, self.f_speed, self.f_mode, self.damp_agg)
+        hdr += '{:>9s}'.format('u_inf')
         for j in range(self.n_modes):
             hdr += ', {:>11s}'.format(f'f_{j}')
         for j in range(self.n_modes):