An awesome postfix (RPN) calculator in python 2 & 3.
$ python postfix.py
Supports commands + - * / ** % sqrt sin cos tan asin acos atan ln log rad deg Re Im =
Trigonometry is done in radians. Use rad and deg to convert to radians and degrees respectively.
Dimensional analysis and dimensioned number support added as of version 8.
Numbers can be input in Python's a+bj format. Comes with pi, e, and i as variables. The answer of the last operation is put into variable \.
Variable Assignment -- The answer of the last operation is put into \
> 2 pi * tau = ; tau = 2*pi
6.28318530718
> tau cos ; cos(tau)
1.0
> 8+3j 2 / ; (8+3i)/2
(4+1.5j)
> \ 2.5 - ; (4+1.5j) - 2.5
(1.5+1.5j)
Arithmetic & Expoentiation
> 2 5 4 - * 4 / ; 2*(5-4)/6
0.3333333333333333
> 2 8 ** ; 2^8
256.0
> 1 2 sqrt / ; 1/sqrt(2)
0.707106781187
Dimensioned Numbers
The calculator supports meters, seconds, kilograms, Kelvin, and Coulomb as m, s, kg, K, C
> 10kg 4s / massflow = ; massflow = 10/4 kg/s
2.5kg/s
> massflow 1.52kg/m^3 / ; 2.5kg/s / 1.52 kg/m^3 = 1.645m^3/s
1.644736842105263m^3/s
> 1.005kg.m^2/s^2/kg/K Cp = ; Specific Heat of Water: 1.005 J/(kg K)
> Cp massflow * 80s * 35K * ; 1.005 J/(kg K) * 2.5 kg/s * 80 s * 35 K = 7035 J
7035kg.m^2/s^2.0
> 4m/s 3s ** ; (4 m/s) ^ (3s) -- Issues a warning
64m/s
> 10kg 20s + ; 10 kg + 20 s -- Issues a warning
30kg
The calculator will only warn when dimensions are potentially misused. It will still return an answer, with either no dimensions, or the dimension of the left-most symbol.
You can also put dimensions on complex numbers, if you're feeling particularly devilish. There will be no warnings.
Logarithms
> e 32 ** ln ; ln(e^32)
32.0
> 1500 10 log ; log_10(1500)
3.17609125906
> 10 \ ** ; 10^3.17609125906
1500.0
Trigonometry -- rad converts to radians, deg converts to degrees
> 30 rad cos asin deg ; 180/pi * asin( cos( 30 * pi/180 ) )
60.0
Complex Numbers -- Python's a+bj format can be used.
> -1 sqrt 0+1j ** ; sqrt(-1)^sqrt(-1)
0.207879576351
> e pi i * ** ; Euler's Identity e^(i*pi) = -1 (plus rounding error)
(-1+1.22464679915e-16j)
> e i 120 rad * ** z = ; z = e^(i*120*pi/180) (A cube root of 1)
(-0.5+0.866025403784j)
> z 3 ** ; z^3 = 1 (plus rounding error)
(1-6.10622663544e-16j)
> z arg deg ; arg(z) * 180/pi
120.0
version 9 (in development)
- (Planned) Full rewrite, implementation of all features in version 8
- (Maybe) Numerical integrator
version 8
- Added dimensional analysis (all S.I. units)
version 7
- Added complex numbers support