Very new to ZKsnarks. I'm trying to build a simple application to check whether the input number matches a certain predefined number or not.
I have followed all the steps mentioned in the SnarkJs doc.
Here is the circuit for my use case:
pragma circom 2.0.0;
template IsZero() {
signal input in;
signal output out;
signal inv;
inv <-- in!=0 ? 1/in : 0;
out <== -in*inv +1;
in*out === 0;
}
template verifier() {
signal input a;
signal output b;
signal c <== 9429723347216097781814234269377894115729242880998740711935743712243189718113;
component isz = IsZero();
a - c ==> isz.in;
isz.out ==> b;
}
component main = verifier();
However, when I try to verify an incorrect witness, the verifier contract still validates it.
This is what I'm doing:
First get the calldata params
proof = await snarkjs.plonk.fullProve( { a: 5}, "circuit_js/circuit.wasm", "circuit_final.zkey");
await snarkjs.plonk.exportSolidityCallData(proof["proof"], proof["publicSignals"]);
Then try to verify with verifier.sol contract. However it still validates it. What I'm doing wrong?
If you want to check whether a is matching the predefined c, you need to have a constraint for that specific check. So it's not enough to assign a - c to the output. You need to have the following constraint: isz.out === 1. Otherwise, b is merely an output. So 5 - 9429723347216097781814234269377894115729242880998740711935743712243189718113 is nonzero, however, there is no violation of any constraint. In fact, you were proving that 5 - 9429723347216097781814234269377894115729242880998740711935743712243189718113 is non-zero, and the circuit output was indeed 0 (false), which is correct. If you add the aforementioned constraint, you can remove the output signal altogether.
Related
I've a buffer that is actually ArrayList<Object>.
Happens async:
This buffer list changes very frequently - I mean 15-50 times in single second and the idea is that whenever there's an update, I remove first element by position buffer.removeAt(0) and add new value in the end by buffer.add(new).
At some point I call a function that goes and do calculation with buffer list. What I do is I go through the list - element by element. At some point I run into NPE as the the element has been removed async.
How to solve this NPE? I was thinking of making deep copy, but making deep copy would mean to go through the buffer list and do some data allocation, which basically means that while I do deep copy I can still run into NPE.
How problems like these are solved?
How to solve NPE?
What would be more optimized way as this is gonna consume a lot of memory?
Code:
private fun observeFrequentData() {
frequentData.observe(owner, Observer { data ->
if (accelerationData == null) return#Observer
GlobalScope.launch {
val a = data[0].toDouble()
val b = data[1].toDouble()
val c = a + b
val timestamp = System.currentTimeMillis()
val customObj = CustomObj(c, timestamp)
if (buffer.size >= 5000) {
buffer.removeAt(0)
}
buffer.add(acceleration)
}
})
}
fun getBuffer() {
val mappedData = buffer.map { it.smth } // NPE, it == null
}
If you are doing lots of removing from 0, and insert at the end. Then ArrayList is probably not the container to use.
you can consider using a LinkedList .
buffer.removeFirst();
and
buffer.add(acceleration);
also note the following comments regarding synchronization.
Note that this implementation is not synchronized. If multiple threads
access a linked list concurrently, and at least one of the threads
modifies the list structurally, it must be synchronized externally. (A
structural modification is any operation that adds or deletes one or
more elements; merely setting the value of an element is not a
structural modification.) This is typically accomplished by
synchronizing on some object that naturally encapsulates the list. If
no such object exists, the list should be "wrapped" using the
Collections.synchronizedList method. This is best done at creation
time, to prevent accidental unsynchronized access to the list:
List list = Collections.synchronizedList(new LinkedList(...));
Using the synchronized keyword on your piece of code as #patrickf suggested.
To take care of performance, instead of making the method call itself synchronized, you can just write the 3 "buffer" related lines of code (size, removeAt and add) in a synchronized block.
Something like;
.
.
.
synchronized {
if (buffer.size >= 5000) {
buffer.removeAt(0)
}
buffer.add(acceleration)
}
}
})
Hope this helps!
We are trying to iterate over a Map, but without any success. We reduced our issue to this minimal example:
def map = [
'monday': 'mon',
'tuesday': 'tue',
]
If we try to iterate with:
map.each{ k, v -> println "${k}:${v}" }
Only the first entry is output: monday:mon
The alternatives we know of are not even able to enter the loop:
for (e in map)
{
println "key = ${e.key}, value = ${e.value}"
}
or
for (Map.Entry<String, String> e: map.entrySet())
{
println "key = ${e.key}, value = ${e.value}"
}
Are failing, both only showing the exception java.io.NotSerializableException: java.util.LinkedHashMap$Entry. (which could be related to an exception occurring while raising the 'real' exception, preventing us from knowing what happened).
We are using latest stable jenkins (2.19.1) with all plugins up-to-date as of today (2016/10/20).
Is there a solution to iterate over elements in a Map within a Jenkins pipeline Groovy script ?
Its been some time since I played with this, but the best way to iterate through maps (and other containers) was with "classical" for loops, or the "for in". See Bug: Mishandling of binary methods accepting Closure
To your specific problem, most (all?) pipeline DSL commands will add a sequence point, with that I mean its possible to save the state of the pipeline and resume it at a later time. Think of waiting for user input for example, you want to keep this state even through a restart.
The result is that every live instance has to be serialized - but the standard Map iterator is unfortunately not serializable. Original Thread
The best solution I can come up with is defining a Function to convert a Map into a list of serializable MapEntries. The function is not using any pipeline steps, so nothing has to be serializable within it.
#NonCPS
def mapToList(depmap) {
def dlist = []
for (def entry2 in depmap) {
dlist.add(new java.util.AbstractMap.SimpleImmutableEntry(entry2.key, entry2.value))
}
dlist
}
This has to be obviously called for each map you want to iterate, but the upside it, that the body of the loop stays the same.
for (def e in mapToList(map))
{
println "key = ${e.key}, value = ${e.value}"
}
You will have to approve the SimpleImmutableEntry constructor the first time, or quite possibly you could work around that by placing the mapToList function in the workflow library.
Or much simpler
for (def key in map.keySet()) {
println "key = ${key}, value = ${map[key]}"
}
I work on test automation for an app that communicates with the server. The app has 7 pre-defined strings. Depending on the info the server returns, which is not deterministic and depends on external factors, the app places one to three of the seven pre-defined strings in a table view as hittable static texts. The user has a choice which of those strings to tap.
To automate this test I need an asynchronous way to determine in the test code which of the 7 pre-defined strings actually appear on the screen.
I cannot use element.exists because it takes time for static texts to appear and I do not want to call sleep() because that would slow down the test.
So I tried to use XCTestExpectation but got a problem. XCTest always fails when waitForExpectationsWithTimeout() times out.
To illustrate the problem I wrote a simple test program:
func testExample() {
let element = XCUIApplication().staticTexts["Email"]
let gotText = haveElement(element)
print("Got text: \(gotText)")
}
func haveElement(element: XCUIElement) -> Bool{
var elementExists = true
let expectation = self.expectationForPredicate(
NSPredicate(format: "exists == true"),
evaluatedWithObject: element,
handler: nil)
self.waitForExpectationsWithTimeout(NSTimeInterval(5)) { error in
elementExists = error == nil
}
return elementExists
}
The test always fails with
Assertion Failure: Asynchronous wait failed: Exceeded timeout of 5 seconds, with unfulfilled expectations: "Expect predicate `exists == 1` for object "Email" StaticText".
I also tried
func haveElement(element: XCUIElement) -> Bool {
var elementExists = false
let actionExpectation = self.expectationWithDescription("Expected element")
dispatch_async(dispatch_get_main_queue()) {
while true {
if element.exists {
actionExpectation.fulfill()
elementExists = true
break
} else {
sleep(1)
}
}
}
self.waitForExpectationsWithTimeout(NSTimeInterval(5)) { error in
elementExists = error == nil
}
return elementExists
}
In this case the test always fails with
Stall on main thread.
error.
So the question is how do I check a presence of an asynchronous UI element that may or may not appear within specified time without the test failing on timeout?
Thank you.
You're overcomplicating the test. If you're communicating with a server, there is unnecessary variability in your tests -- my suggestion is to use stubbed network data for each case.
You can get a brief introduction to stubbing network data here:
http://masilotti.com/ui-testing-stub-network-data/
You will eliminate the randomness in the test based on response time of the server as well as the randomness of which string is appearing. Create test cases that respond to each case (i.e, how the app responds when you tap on each individual string)
I am trying to find an example about the LTL operator _ F_ which means fatally with Aorai but i can't figure out exactly what this operator aims and there are no examples in the repository "tests" of Aorai
For example, i wrote this formula
CALL(main) && _X_ (CALL(a) && _X_(RETURN(a) && _F_ (RETURN(b) && _X_ (RETURN(main)) ) ))
which says that in my program main, i have to call the function a() and after this i don't understand what happens with the operator fatally but it seems that it takes and accepts whatever we call after the function a() with no warning or error from Aorai. If anybody could help me or could give a right example about it.
For example, i have this program below which i would like to test with this formula above
void a()
{}
void b()
{}
int main()
{ a();
a();
b();
b();
a();
return 0;}
I type frama-c -aorai-ltl test.ltl test.c
Normally, there should be an error or warning from Aorai. No?
Your question is more about temporal logic than Frama-C/Aorai itself, but the meaning of this formula is that main must call a, then do whatever it wants, before calling b and returning just after that.
NB: note that Aorai only traces call and return events, so that e.g. "just after" here means that main cannot not call any function after its last call to b, but can still perform some actions, such as x++;.
Update
I've run your complete example on Frama-C. Indeed a post-condition is missing in the contract for main generated by Aorai, namely that the state of the generated automaton at the end of main (T0_S4) is supposed to be accepting, which is not the case here. This is a bug. If you write explicitely an equivalent automaton in the ya language, as
%init: S0;
%accept: Sf;
S0: { CALL(main) } -> S1;
S1: { [ a() ] } -> S2;
S2: { RETURN(b) } -> S3
| other -> S2;
S3: { RETURN(main) } -> Sf;
Sf: -> Sf;
Then the generated contract for main contains a requires \false;, which indeed indicates that the function is not conforming to the automaton, and Aoraï warns about that.
Please note however that in the general case, Aoraï will not emit any warning. It generates contracts that, if fulfilled, imply that the whole program is conforming to the automaton. The proof of the contract must be done by another plugin (e.g. WP or Value Analysis)
I have a map:
var sessions = map[string] chan int{}
How do I delete sessions[key]? I tried:
sessions[key] = nil,false;
That didn't work.
Update (November 2011):
The special syntax for deleting map entries is removed in Go version 1:
Go 1 will remove the special map assignment and introduce a new built-in function, delete: delete(m, x) will delete the map entry retrieved by the expression m[x]. ...
Go introduced a delete(map, key) function:
package main
func main () {
var sessions = map[string] chan int{};
delete(sessions, "moo");
}
Copied from Go 1 release notes
In the old language, to delete the entry with key k from the map represented by m, one wrote the statement,
m[k] = value, false
This syntax was a peculiar special case, the only two-to-one assignment. It required passing a value (usually ignored) that is evaluated but discarded, plus a boolean that was nearly always the constant false. It did the job but was odd and a point of contention.
In Go 1, that syntax has gone; instead there is a new built-in function, delete. The call
delete(m, k)
will delete the map entry retrieved by the expression m[k]. There is no return value. Deleting a non-existent entry is a no-op.
Updating: Running go fix will convert expressions of the form m[k] = value, false into delete(m, k) when it is clear that the ignored value can be safely discarded from the program and false refers to the predefined boolean constant. The fix tool will flag other uses of the syntax for inspection by the programmer.
From Effective Go:
To delete a map entry, use the delete built-in function, whose arguments are the map and the key to be deleted. It's safe to do this even if the key is already absent from the map.
delete(timeZone, "PDT") // Now on Standard Time
delete(sessions, "anykey")
These days, nothing will crash.
Use make (chan int) instead of nil. The first value has to be the same type that your map holds.
package main
import "fmt"
func main() {
var sessions = map[string] chan int{}
sessions["somekey"] = make(chan int)
fmt.Printf ("%d\n", len(sessions)) // 1
// Remove somekey's value from sessions
delete(sessions, "somekey")
fmt.Printf ("%d\n", len(sessions)) // 0
}
UPDATE: Corrected my answer.