update fargan to match version 45

dnn/torch/fargan/rc.py

@@ -0,0 +1,29 @@
+import torch
+
+
+
+def rc2lpc(rc):
+    order = rc.shape[-1]
+    lpc=rc[...,0:1]
+    for i in range(1, order):
+        lpc = torch.cat([lpc + rc[...,i:i+1]*torch.flip(lpc,dims=(-1,)), rc[...,i:i+1]], -1)
+        #print("to:", lpc)
+    return lpc
+
+def lpc2rc(lpc):
+    order = lpc.shape[-1]
+    rc = lpc[...,-1:]
+    for i in range(order-1, 0, -1):
+        ki = lpc[...,-1:]
+        lpc = lpc[...,:-1]
+        lpc = (lpc - ki*torch.flip(lpc,dims=(-1,)))/(1 - ki*ki)
+        rc = torch.cat([lpc[...,-1:] , rc], -1)
+    return rc
+
+if __name__ == "__main__":
+    rc = torch.tensor([[.5, -.5, .6, -.6]])
+    print(rc)
+    lpc = rc2lpc(rc)
+    print(lpc)
+    rc2 = lpc2rc(lpc)
+    print(rc2)