In [1]:

    

from pmesh.pm import ParticleMesh, RealField, ComplexField

# a 8^3 mesh
pm = ParticleMesh(Nmesh=[8,8,8])

# initialize a RealField
rfield = RealField(pm)

# shape
print("shape = ", rfield.shape)

# set entire mesh to unity
rfield[...] = 1.0

# print the mean of the underlying array
print("mean = ", rfield.value.mean())


    

    




shape =  (8, 8, 8)
mean =  1.0

In [2]:

    

# perform the forward FFT
cfield = rfield.r2c()

# stores Nmesh/2+1 in z axis b/c of conjugate symmetry
print("shape = ", cfield.shape)

# k=0 mode is the mean value of configuration space field
print("mean of configuration space field from k=0 = ", cfield[0,0,0])

# perform the inverse FFT
rfield2 = cfield.c2r()

# print the mean of the underlying array
print("mean of real field = ", rfield2.value.mean())


    

    




shape =  (8, 8, 5)
mean of configuration space field from k=0 =  (1+0j)
mean of real field =  1.0