logic

I'm trying to represent temporal constraints in SMT-LIB in order to check their satisfiability. I'm looking for feedback on the direction I'm taking. I'm relatively new to SMT-LIB and I'll highly appreciate inputs. The constraints that I have are about the time and duration of events. For example, consider the following constraints given in natural language: John started writing an essay at 13:03:41, and it took him 20 min to complete it. After writing, he checked his emails, which took him more than 40 min. After checking his emails, he phoned his wife. He phoned his wife after 14:00:00. It

I know this question has been asked before, however, when I am trying to do an if statement and I am getting an error. I looked at this link , but did not help much in my case. My dfs is a list of DataFrames. I am trying the following, for i in dfs: if (i['var1'] < 3.000): print(i) Gives the following error: ValueError: The truth value of a Series is ambiguous. Use a.empty, a.bool(), a.item(), a.any() or a.all(). AND I tried the following and getting the same error. for i,j in enumerate(dfs): if (j['var1'] < 3.000): print(i) My var1 data type is float32 . I am not using any other logical

I've searched the web but I've found no solution to this problem. What is the logical priority for operators NAND , NOR and XNOR ? I mean, considering as example the expression A AND B NAND C which operator should be evaluated first? Obviously NAND can be translated as NOT-AND (as NOR is NOT-OR and XNOR is NOT-XOR ), but (A AND B) NAND C != A AND (B NAND C) = A AND NOT(B AND C) According to my researches there's no a defined priority for such an expression, so I think the simplest solution is to evaluate the operators according to the order they appear in the expression, but I may be wrong.

A friend of mine came to me with this strange behavior which i can't explain, any insight view would be appreciated. Im running VS 2005 (C# 2.0), the following code show the behavior int rr = "test".IndexOf(""); Console.WriteLine(rr.ToString()); the above code, print "0" which clearly show it should have return -1 This also happen in Java where the following Class show the behavior: public class Test{ public static void main(String[] args){ System.out.println("Result->"+("test".indexOf(""))); } } Im running Java 1.6.0_17 This is not an exception to the rule, but rather a natural consequence of

What is wrong with my power function? pow(_,0,1). pow(X,Y,Z) :- pow(X,Y-1,X*Z). ?- pow(2,3,Z). ERROR: Out of global stack Your Y does not get decremented, you can not use predicates like functions. You also have to unify Z with the result of the multiplication. pow(_,0,1). pow(X,Y,Z) :- Y1 is Y - 1, pow(X,Y1,Z1), Z is Z1*X. There is also a builtin power function which will be much faster: pow2(X,Y,Z) :- Z is X**Y. Also note that pow is not a last call and can not be optimized to use only one stack frame. You should reformulate it to: pow3(X,Y,Z) :- powend(X,Y,1,Z),!. powend(_,0,A,Z) :- Z is A.

I am asked to develop a software which should be able to create Flow chart/ Control Flow of the input Java source code. So I started researching on it and arrived at following solutions: To create flow chart/control flow I have to recognize controlling statements and function calls made in the given source code Now I have two ways of recognizing: Parse the Source code by writing my own grammars (A complex solution I think). I am thinking to use Antlr for this. Read input source code files as text and search for the specific patterns (May become inefficient) Am I right here? Or I am missing