So, I am pretty new to prolog (started just yesterday) and I have next problem:
Скласти програму на Пролозі, що встановлює зв’язок по закону Ома (зв'язок між струмом, напругою і опором) для 2 резисторів - послідовних і паралельних.
or
Create a program in Prolog that establishes the relationship between Ohm's law (the relationship between current, voltage and resistance) for 2 resistors - series and parallel.
and I have got to this point:
% vim: set filetype=prolog :
% problem2.pl
% I1 - струм на резисторі 1 current of resistor 1
% I2 - струм на резисторі 2 current on resistor 2
% V1 - напруга на резисторі 1 voltage on resistor 1
% V2 - напруга на резисторі 2 voltage on resistor 2
% R1 - опір резистора 1 resistance of resistor 1
% R2 - опір резистора 2 resistance of resistor 2
% I - струм в колі total current
% V - напруга в колі total voltage
% R - опір кола total resistance
% загальні закони ohms law%
% I = U / R
p_ohm(I, I1, I2, V, V1, V2, R, R1, R2) :-
% паралельне зʼєднання parallel circuit
(I1 is V / R1;
I1 is V1 / R1;
I1 is V2 / R1;
I1 is I - I2),
(I2 is V / R1;
I2 is V1 / R1;
I2 is V2 / R1;
I2 is I - I1),
(I is I1 + I2;
I is V /R;
I is V1 / R;
I is V2 / R),
(R1 is V1 / I1;
R1 is V2 / I1;
R1 is V / I1;
R2 is V1 / I2;
R2 is V2 / I2;
R2 is V / I2),
(R is V / I;
R is 1 / (1 / R1 + 1 / R2)),
(V is R * I;
V is V1;
V is V2
V is R1 * I1;
V is R2 * I2),
( V1 is V;
V1 is V2;
V1 is I1 * R1),
(V2 is V;
V2 is V1;
V2 is I2 * R2).
I have took the parallel circuit properties from here.
And the problem is that this wont work.
➜ ~ swipl b.pl
Welcome to SWI-Prolog (threaded, 64 bits, version 9.0.4)
SWI-Prolog comes with ABSOLUTELY NO WARRANTY. This is free software.
Please run ?- license. for legal details.
For online help and background, visit https://www.swi-prolog.org
For built-in help, use ?- help(Topic). or ?- apropos(Word).
?- p_ohm(I, I1, 1, 6, V1, V2, R, 1, R2).
ERROR: Arguments are not sufficiently instantiated
ERROR: In:
ERROR: [11] 1 is _14408/1
ERROR: [10] p_ohm(_14434,6,1,6,_14442,_14444,_14446,1,_14450) at /Users/vladyslav/b.pl:25
ERROR: [9] toplevel_call(user:user: ...) at /opt/homebrew/Cellar/swi-prolog/9.0.4/libexec/lib/swipl/boot/toplevel.pl:1173
?-
Maybe this is because it tries to satisfy I1 is V / R1; but V is undefined at the moment.
?- debug.
true.
[debug] ?- p_ohm(I, I1, 1, 6, V1, V2, R, 1, R2).
ERROR: Arguments are not sufficiently instantiated
ERROR: In:
ERROR: [11] 1 is _5272/1
ERROR: [10] p_ohm(_5298,6,1,6,_5306,_5308,_5310,1,_5314) at /Users/vladyslav/b.pl:25
ERROR: [9] toplevel_call(user:user: ...) at /opt/homebrew/Cellar/swi-prolog/9.0.4/libexec/lib/swipl/boot/toplevel.pl:1173
Exception: (11) 1 is _4162/1 ?
BUT there is ; at the end of I1 is V / R1; that means OR. I don't understand.
The values for p_ohm(I, I1, 1, 6, V1, V2, R, 1, R2) were taken from real physics book problem about two parallel resistors.
I have no idea how to solve that problem in prolog because he tries to satisfy everything (or what?). And also I have poor understanding of its syntax... I cant use predicates as functions to operate on numbers. How to solve the problem at the start of question without suck errors?
Examining the error message:
ERROR: Arguments are not sufficiently instantiated
ERROR: In:
ERROR: [11] 1 is _14408/1
ERROR: [10] ... at /Users/vladyslav/b.pl:25
This means: the error is on line 25.
Rearrange the equation so that the uninstantiated variable is to the left of the is, and the instantiated variables are on the right - which is how is is meant to be used.
To handle uninstantiated variables more elegantly, look at: