In computer science, a predicate is called an invariant to a sequence of operations provided that: if the predicate is true before starting the sequence, then it is true at the end of the sequence.
In loops, invariants are data structures referenced within the loop that do not change during any iteration. In design-by-contract, invariants are invariants are properties of a class than must be satisfied at the end of any method call that is invoked from outside of the class itself.
Assume this algorithm which gives the maximal sum of a subarray back. And let a[] be an array of length n.
randmax = 0
maximum = 0
for 0 <= i < n
randmax = randmax + a_i
if randmax > max
max = randmax
if randmax < 0
randmax =…
I'm revising algorithms for my exams and I was trying to solve this exercise but I couldn't come up with a solution.
This is the pseudo-code.
1. int search (int [] a, int x) {
2. // Pre: ∃i:Nat (0≤i
I have a method look like this.
public void some(..., Collection collection) {
// WOOT, PECS!!!
final Stream stream = getStream();
stream.collect(toCollection(() -> collection));
}
And how can I make this method…
im currently working on SIFT algorithm. i want to ask how do we rotate 16x16 gradient magnitude in difference for 10 degree because the orientation bin 10 degree difference?
and then when we know the maximum gradient orientation example its 200 and…
Why invariant function has this params:
function(condition, format, a, b, c, d, e, f) {
instead of:
function invariant(condition : any, format?: string, ...args : Array < any >) {
Can anyone clarify, because for me does not make any…
In Eiffel, it is possible to specify a type with an 'anchored declaration'.
I wonder if the relevant invariants in the class also apply to an anchored declaration:
class C
feature
f: INTEGER
do
... Do something ...
…
I'm trying to display only a segment of an array of queries that I've mapped from state to the props of my container component (using mapStateToProps).
To do this, I use the spread operator, Array.slice, and then iterate over sub-array to create…
I am always wondering how to prove the correctness of a simple program. For example, a interview problem like First Missing Positive. The program looks like this:
public class Solution{
public int firstMissingPositive(int[] A){
int i =…
I use a free pascal lazarus. I have DBGrid that loads table from DB. I created columns in designer and sqlqueries to these columns. Everything is excellent. But when i need to get type of field i get an error: Project Admin raised exception class…
When I use ToLowerInvariant or ToUpperInvariant they don't work in lambda expressions.
I get an exception:
LINQ to Entities does not recognize the method 'System.String ToUpperInvariant()' method, and this method cannot be translated into a store…
I'd like to learn more about Timed Automata to verify real-time systems. Currently, I'm trying to get myself familiar with a tool called UPPAAL.
I drew some simple graphs and added different properties. The entire model is supposed to represent a…
I am wondering if there is in the literature a clustering algorithm whose output (partition, dendrogram, soft assignments and so on) is invariant to :
permutation in the data points (typically many hierarchical agglomerative clustering are…
I need hep working out what the invariant for this code would be. I think there can be multiple invariants but i don't really understand the topic and online resources i have found still dont really help. The code i made for the binary search…
Is there a convenient way to enforce a method's input and output invariants, when the method is overridden in a subclass?
By enforcing invariants, I mean checking things like:
The number of input arguments
The types of some/all of the inputs
The…
I'm having issues trying to understand the word "invariant" and "variant" and how it relates to programming in c. It's used a lot in my textbook and its mentioned quite often by my professor but I can't seem to properly understand it even after…
