Fix projection 3d for old matplotlib versions

fourier/06_direct_fourier.py

@@ -10,6 +10,7 @@ in a continuous fashion
 if __name__ == "__main__":
     import numpy as np
     import matplotlib.pyplot as plt
+    from mpl_toolkits.mplot3d import Axes3D
 
     from mylib.fft import direct_fourier_transform
 
@@ -60,7 +61,7 @@ if __name__ == "__main__":
     freq_cmap = cmap(freq_norm(test_freqs))
     try:
         # Amplitudes Histogram
-        if False:
+        if True:
             fig = plt.figure()
             ax = fig.add_subplot(projection='3d')
             ax.set_xlabel("Amplitude")
@@ -145,7 +146,7 @@ if __name__ == "__main__":
                     ax.plot(tmp_test_freqs, func_amps, ls='dotted', color=l[0].get_color())
 
         # Amplitudes figure
-        if not True:
+        if True:
             fig, ax = plt.subplots()
             ax.set_ylabel("Amplitude")
             ax.set_xlabel("Frequency")