litex/examples/sim/cordic_err.py

110 lines
3.3 KiB
Python

import random
import numpy as np
import matplotlib.pyplot as plt
from migen.fhdl.std import *
from migen.fhdl import verilog
from migen.genlib.cordic import Cordic
from migen.sim.generic import run_simulation
class TestBench(Module):
def __init__(self, n=None, xmax=.98, i=None, **kwargs):
self.submodules.cordic = Cordic(**kwargs)
if n is None:
n = 1<<flen(self.cordic.xi)
self.c = c = 2**(flen(self.cordic.xi) - 1)
self.cz = cz = 2**(flen(self.cordic.zi) - 1)
x = int(xmax*c/self.cordic.gain)
if i is None:
i = [(x, 0, int(cz*(2.*ii/n - 1))) for ii in range(n)]
self.i = i
random.shuffle(self.i)
self.ii = iter(self.i)
self.o = []
def do_simulation(self, selfp):
if selfp.cordic.new_out:
self.o.append((selfp.cordic.xo, selfp.cordic.yo, selfp.cordic.zo))
if selfp.cordic.new_in:
try:
selfp.cordic.xi, selfp.cordic.yi, selfp.cordic.zi = next(self.ii)
except StopIteration:
raise StopSimulation
def run_io(self):
run_simulation(self)
del self.o[0]
if self.i[0] != (0, 0, 0):
assert self.o[0] != (0, 0, 0)
#if self.i[-1] != self.i[-2]:
# assert self.o[-1] != self.o[-2], self.o[-2:]
def rms_err(width, guard=None, stages=None, n=None):
tb = TestBench(width=width, guard=guard, stages=stages,
n=n, eval_mode="combinatorial")
tb.run_io()
c = 2**(flen(tb.cordic.xi) - 1)
cz = 2**(flen(tb.cordic.zi) - 1)
g = tb.cordic.gain
xi, yi, zi = np.array(tb.i).T/c
zi *= c/cz*tb.cordic.zmax
xo1, yo1, zo1 = np.array(tb.o).T
xo = np.floor(c*g*(np.cos(zi)*xi - np.sin(zi)*yi))
yo = np.floor(c*g*(np.sin(zi)*xi + np.cos(zi)*yi))
dx = xo1 - xo
dy = yo1 - yo
mm = np.fabs([dx, dy]).max()
rms = np.sqrt(dx**2 + dy**2).sum()/len(xo)
return rms, mm
def rms_err_map():
widths, stages = np.mgrid[8:33:1, 8:37:1]
errf = np.vectorize(lambda w, s: rms_err(int(w), None, int(s), n=333))
err = errf(widths, stages)
print(err)
lev = np.arange(10)
fig, ax = plt.subplots()
c1 = ax.contour(widths, stages, err[0], lev/10, cmap=plt.cm.Greys_r)
c2 = ax.contour(widths, stages, err[1], lev, cmap=plt.cm.Reds_r)
ax.plot(widths[:, 0], stages[0, np.argmin(err[0], 1)], "ko")
ax.plot(widths[:, 0], stages[0, np.argmin(err[1], 1)], "ro")
print(widths[:, 0], stages[0, np.argmin(err[0], 1)],
stages[0, np.argmin(err[1], 1)])
ax.set_xlabel("width")
ax.set_ylabel("stages")
ax.grid("on")
fig.colorbar(c1)
fig.colorbar(c2)
fig.savefig("cordic_rms.pdf")
def plot_function(**kwargs):
tb = TestBench(eval_mode="combinatorial", **kwargs)
tb.run_io()
c = 2**(flen(tb.cordic.xi) - 1)
cz = 2**(flen(tb.cordic.zi) - 1)
g = tb.cordic.gain
xi, yi, zi = np.array(tb.i).T
xo, yo, zo = np.array(tb.o).T
fig, ax = plt.subplots()
#ax.plot(zi, xo-np.around(xi[0]*g*np.cos(zi/cz*np.pi)), "k-")
ax.plot(zi, xo, "r,")
ax.plot(zi, yo, "g,")
ax.plot(zi, zo, "b,")
if __name__ == "__main__":
c = Cordic(width=16, guard=None, eval_mode="combinatorial")
print(verilog.convert(c, ios={c.xi, c.yi, c.zi, c.xo, c.yo, c.zo,
c.new_in, c.new_out}))
#print(rms_err(8))
#rms_err_map()
#plot_function(func_mode="hyperbolic", xmax=.3, width=16, n=333)
#plot_function(func_mode="circular", width=16, n=333)
#plot_function(func_mode="hyperbolic", cordic_mode="vector",
# xmax=.3, width=16, n=333)
plot_function(func_mode="circular",
width=16, stages=15, guard=0,
n=1000, xmax=.98)
plt.show()