blob: 6742c90dfefb8ccd92cce7013b83125e0c055796 [file] [log] [blame]
# compute arctangent table for CORDIC computations in fttrigon.c
import sys, math
#units = 64*65536.0 # don't change !!
units = 180 * 2**16
scale = units/math.pi
shrink = 1.0
comma = ""
print ""
print "table of arctan( 1/2^n ) for PI = " + repr(units/65536.0) + " units"
for n in range(1,32):
x = 0.5**n # tangent value
angle = math.atan(x) # arctangent
angle2 = round(angle*scale) # arctangent in FT_Angle units
if angle2 <= 0:
break
sys.stdout.write( comma + repr( int(angle2) ) )
comma = ", "
shrink /= math.sqrt( 1 + x*x )
print
print "shrink factor = " + repr( shrink )
print "shrink factor 2 = " + repr( int( shrink * (2**32) ) )
print "expansion factor = " + repr( 1/shrink )
print ""