Missing precision

I have trouble calculating a relatively simple expression “log(8/(2pi5cos(7/5)^2))(2*5)^(-8)” to the desired precision.

My code

import mpmath as mpm
from mpmath import mpf
mpm.dps = 100; # Target (decimal) precision

# Trying to calculate 
mpmmp = mpm.log(8/(2*mpm.pi*5*mpm.cos(7/5)**2))*(2*5)**(-8)
# also tried, but gives the same result:
# mpmmp = mpm.log(mpf(8)/(mpf(2)*mpm.pi*mpf(5)*mpm.cos(mpf(7)/mpf(5))**mpf(2)))*(mpf(2)*mpf(5))**(-mpf(8))
print(N(mpmmp, 50))

# Same thing in Wolfram Alpha https://www.wolframalpha.com/input?i=+log%288%2F%282*pi*5*cos%287%2F5%29%5E2%29%29*%282*5%29%5E%28-8%29
wamp = mpm.mpf("2.1764268381757881245184989320757924235425037995295963369536875540976739004791583229859268345586450088673471866819775813945E-8")
print(N(wamp, 50))

print(N(mpmmp-wamp, 50))

With the result

0.000000021764268381757866721875713136684360460293419237132
0.000000021764268381757879956765513985127158402832492356538
-1.3234889800848442797942539073119405657052993774414e-23

Why do they not match?

[To3No7]

Ah, the “mpm.mp.dps = 100” solved it!

So many hours of frustration this has solved! Many Thanks!

[WarrenWeckesser]

As I wrote in a comment I have already tried:

Sorry! I guess I skimmed the rest after seeing the mistakes in the code that is not commented out.

The problem is this line:

mpm.dps = 100; # Target (decimal) precision

It should be

mpm.mp.dps = 100  # Target (decimal) precision