from fft import fft
from bits import bitrev, bitlen

t = [ 1+2j, 3+4j ]

# since fft() overwrites the input values, to keep the original t
# we have to explicitly copy the values, not the complex objects
#
x = [complex(t[i].real,t[i].imag) for i in range(len(t))]
print( "x =", x)
fft(x,pre=False)
print( "fft(x,pre=False) =", x)

# precompute W
#
x = [complex(t[i].real,t[i].imag) for i in range(len(t))]
print( "\nx =", x)
fft(x)
print( "fft(x) =", x)

# use precomputed W
#
x = [complex(t[i].real,t[i].imag) for i in range(len(t))]
print( "\nx =", x)
fft(x)
print( "fft(x) =", x)

# conjugate W
#
print( "\nx =", x)
fft(x,inv=True)
print( "fft(x,inv=True) =", x)

# x size change, should precompute new W
#
t = [ 1+2j, 3+4j, 3+4j, 1+2j ]
x = [complex(t[i].real,t[i].imag) for i in range(len(t))]
print( "\nx =", x)
fft(x)
print( "fft(x) =", x)

# test inverse
#
N = len(x)
nbits = bitlen(N-1)
y = [x[bitrev(i,nbits)] for i in range(N)]
print( "\ny =", y)
fft(y,inv=True)
print( "fft(y,inv=True) =", y)
z = [y[bitrev(i,nbits)]/N for i in range(N)]
print( "z =", z)