I'm stuck with computing the integral at each point of an array. The idea is first to create a function ("Integrand"). Then, create a second function ("MyConvolve") that computes the necessary integral.
Here's what I did up to now:
Integrand = function(s,x)
{ 1/4*(abs(x-s)<=1)*(abs(s)<=1) }
MyConvolve = function(func,data)
{ return( integrate(func, lower=-Inf, upper=Inf, data) ) }
Now, running the code with some array, I get an error message:
SomeMatrix = replicate(10, rnorm(10))
MyConvolve(Integrand, SomeMatrix)
Which ends up with the following error message:
Error in integrate(func, lower = -Inf, upper = Inf, data) :
evaluation of function gave a result of wrong length
I already tried vectorizing the function, but still ended up with error messages.
Thank you very much for your help!
I am not sure I understand what you are trying to compute,
but if you want to evaluate MyConvolve(Integrand,s),
where s takes all the values in SomeMatrix,
then apply is sufficient.
sapply( SomeMatrix, function(s) MyConvolve( Integrand, s )$value )
However, the dimensions of the matrix are lost.
You can recover them as follows:
result <- SomeMatrix
result[] <- sapply( SomeMatrix, function(s) MyConvolve( Integrand, s )$value )
Related
I'm following tutorial from the official Microsoft learning page (https://learn.microsoft.com/en-us/azure/quantum/tutorial-qdk-explore-entanglement?pivots=ide-azure-portal) about quantum entanglement.
Basically, I copied an example posted there and I am getting error:
QS5026 The variable "numOnesQ1" cannot be reassigned here. In conditional blocks that depend on a measurement result, the target QuantinuumProcessor only supports reassigning variables that were declared within the block.
I understand what it says but it's just a copy from the official Microsoft tutorial. Am I missing something simple like imports, wrong settings? If not, how can I in other way set variables declared outside conditional blocks that depend on a measurement result?
Here is my code:
namespace Quantum.QuantumDream {
open Microsoft.Quantum.Canon;
open Microsoft.Quantum.Intrinsic;
operation GetRandomResult() : Result {
use q = Qubit();
H(q);
return M(q);
}
#EntryPoint()
operation TestBellState(count : Int, initial : Result) : (Int, Int, Int, Int) {
mutable numOnesQ1 = 0;
mutable numOnesQ2 = 0;
// allocate the qubits
use (q1, q2) = (Qubit(), Qubit());
for test in 1..count {
SetQubitState(initial, q1);
SetQubitState(Zero, q2);
// measure each qubit
let resultQ1 = M(q1);
let resultQ2 = M(q2);
// Count the number of 'Ones':
if resultQ1 == One {
set numOnesQ1 += 1;
}
if resultQ2 == One {
set numOnesQ2 += 1;
}
}
// reset the qubits
SetQubitState(Zero, q1);
SetQubitState(Zero, q2);
// Return number of |0> states, number of |1> states
Message("q1:Zero, One q2:Zero, One");
return (count - numOnesQ1, numOnesQ1, count - numOnesQ2, numOnesQ2 );
}
operation SetQubitState(desired : Result, target : Qubit) : Unit {
if desired != M(target) {
X(target);
}
}
}
This tutorial code is only supposed to run on a local simulator (using %simulate magic commands in a Jupyter Notebook). From the error message, it looks like you've tried to run it on one of Quantinuum targets, which have some limitations on the kinds of things you can do in the code. To run equivalent code on Quantinuum, you'd need to define an operation for just the body of the loop (preparing a state and measuring it) and run it as a job - the cloud targets will take care of the loop themselves, running your code multiple times and returning to you a histogram of the results. For an example, you can see the QRNG sample in the samples gallery in Azure Portal.
So I'm trying to get a standard deviation function to work, however I'm running into an error. Here's my code:
func standardDeviation(dataSet: [Double]) -> Double {
let mean = dataSet.reduce(0, +) / Double(dataSet.count)
var distances = [Double]()
for number in dataSet {
let distanceFromMean = (dataSet[Int(number)] - mean)
distances.append(distanceFromMean * distanceFromMean)
}
return distances.reduce(0, +) / Double(dataSet.count)
}
It outputs the following error:
Fatal Error: Index out of range
So, I had a feeling that it was something to do when I call the dataSet array, so when I looked into that, I found this as an error
error: Execution was interrupted, reason: EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0).
The process has been left at the point where it was interrupted, use "thread return -x" to return to the state before expression evaluation.
number (a Double!) cannot be an index to subscribe dataSet, so I'm quite sure you mean
let distanceFromMean = number - mean
as in the Fast Enumeration pattern the index variable number is actually equal to array[index]
String color1 = moreColors.get(0);
String color2 = moreColors[0];
System.assertEquals(color1, color2);
// Iterate over a list to read elements
for(Integer i=0;i<colors.size();i++) {
// Write value to the debug log
System.debug(colors[i]);
}
I am learning Apex and just started what is meaning of line System.assertEquals(color1, color2); and what is mean by debug log here?
System.assert, System.assertEquals, System.assertNotEquals. I argue these are three of the most important method calls in Apex.
These are assert statements. They are used in testing to validate that the data you have matches your expectations.
System.assert tests an logical statement. If the statement evaluates to True, the code keeps running. If the statement evaluates to False, the code throws an exception.
System.assertEquals tests that two values are equal. If the two are equal, the code keeps running. If they are not equal, the code throws an exception.
System.assertNotEqual tests that two values are not equal. If the two are not equal, the code keeps running. If they are equal, the code throws an exception.
These are critical for completing system testing. In Apex Code, you must have 75% line test coverage. Many people do this by generating test code that simply covers 75% of their lines of code. However, this is an incomplete test. A good test class actually tests that the code does what you expect. This is really great to ensure that your code actually works. This makes debugging and regression testing far easier. For example. Lets create a method called square(Integer i) that squares the integer returned.
public static Integer square( Integer i ) {
return i * i;
}
A poor test method would simply be:
#isTest
public static void test_squar() {
square( 1 );
}
A good test method could be:
#isTest
public static void test_square() {
Integer i;
Integer ret_square;
i = 3;
ret_square = square( i );
System.assertEquals( i * i; ret_square );
}
How I would probably write it is like this:
#isTest
public static void test_square() {
for( Integer i = 0; i < MAX_TEST_RUNS; i++ ) {
System.assertEquals( i*i, square( i ) );
}
}
Good testing practices are integral to being a good developer. Look up more on Testing-Driven Development. https://en.wikipedia.org/wiki/Test-driven_development
Line by Line ...
//Get color in position 0 of moreColors list using the list get method store in string color1
String color1 = moreColors.get(0);
//Get color in position 0 of moreColors list using array notation store in string color2,
//basically getting the same value in a different way
String color2 = moreColors[0];
//Assert that the values are the same, throws exception if false
System.assertEquals(color1, color2);
// Iterate over a list to read elements
for(Integer i=0;i<colors.size();i++) {
// Write value to the debug log
System.debug(colors[i]);//Writes the value of color list ith position to the debug log
}
If you are running this code anonymously via the Developer console you can look for lines prefixed with DEBUG| to find the statements, for e.g.
16:09:32:001 USER_DEBUG 1|DEBUG| blue
More about system methods can be found at https://developer.salesforce.com/docs/atlas.en-us.apexcode.meta/apexcode/apex_methods_system_system.htm#apex_System_System_methods
I am stuck doing this even though I know it's very simple. Yet, I am getting errors.
What I have:
I have 3 arrays.
1st Array contains objects of UpgradeButton class.
2nd Array contains objects of BuyButtonclass.
3rd Array named newCostlyShops contains Numbers.
BuyButton class and UpgradeButton class, both have a shopCode member which is a number; the number which I'm trying to equate.
What I'm trying to do:
My goal is to first look for BuyButton and UpgradeButton objects in the respective arrays which have shopCodes same as those in newCostlyShops.
After that, I removeChild() that object and splice it out from the array.
My Code:
Array 3:
var newCostlyShops:Array = new Array();
newCostlyShops = Object(root).WorkScreen_mc.returnCostlyShops();
trace(newCostlyShops); // this is tracing out the exact shopCodes I want and is working fine.
Deletion and Splicing codes:
for (looper = 0; looper < upgradeButtonsArray.length; looper++) {
for (var secondLooper: int = 0; secondLooper < newCostlyShops.length; secondLooper++) {
if (upgradeButtonsArray[looper].shopCode == newCostlyShops[secondLooper]) {
trace(looper);
trace(upgradeButtonsArray[looper]);
removeChild(upgradeButtonsArray[looper]);
upgradeButtonsArray.splice(looper, 1);
}
}
}
for (looper = 0; looper < buyButtonsArray.length; looper++) {
for (secondLooper = 0; secondLooper < newCostlyShops.length; secondLooper++) {
if (buyButtonsArray[looper].shopCode == newCostlyShops[secondLooper]) {
trace(looper);
trace(buyButtonsArray[looper]);
removeChild(buyButtonsArray[looper]);
buyButtonsArray.splice(looper, 1);
}
}
}
What's wrong with this Code:
I keep getting error
TypeError: Error #1010: A term is undefined and has no properties.
This error comes only after the 1st time this code is run and not the first time it is run. When I remove the removeChild and splice , this traces out objects that are not null, ever. Even after this whole function is called 100 times, the error is not shown. Only when I removeChild and use splice this occurs.
Is there something wrong with what I'm doing? How to avoid this error? This is throwing the whole program haywire. If there is any other alternative to this method, I'm open to take those methods as well as long as I don't get errors and my goal is reached.
It might sounds funny, but.... try to decrement looper after splicing.
trace(looper);
trace(upgradeButtonsArray[looper]);
removeChild(upgradeButtonsArray[looper]);
upgradeButtonsArray.splice(looper, 1);
looper--;
I think after splicing the array all item's are being shifted and you're skipping next one.
Also, you should get some more information with this error, like which class/line is throwing it. Maybe you need to enable "permit debugging" or something?
Bonus suggestion:
For newCostlyShops use Dictionary instead of Array so you won't have to nest for inside for...
Using Object or * as a type for a Vector doesn't provide generic functionality (like List in Java). Witness:
public static function someGenericVectorUtil (value:Vector.<*>) :void {
// do stuff to/with the Vector
}
var someVector:Vector.<Number>;
someGenericVectorUtil(someVector); // compile-time implicit coercion error
So, perhaps we redefine the utility method to accept an Array. But there's no easy way to convert Vectors going into the utility to Arrays, nor an easy way to pack them back in afterwards, resulting in code like this:
public static function someGenericArrayUtil (value:Array) :void {
// do stuff to/with the formerly-known-as-Vector
}
var someVector:Vector.<Number>;
var tempArray:Array = new Array(someVector.length);
for (var i:uint=0; i<someVector.length; i++) {
tempArray[i] = someVector[i];
}
someGenericVectorUtil(tempArray);
someVector = Vector.<Number>([tempArray]);
Needless to say, that's pretty hideous. Okay, so let's move the Vector-Array-Vector nonsense into a utility:
public static function vectorToArray (Vector.<*>) :Array {
// oh wait....that Vector.<*> param is useless,
// as demonstrated earlier.
}
Any way to straighten out this mess? Or should I just stop using Vectors when I think I might need to run them through generic utilities? (Obviously, also not really much of an option...)
public static function someGenericVectorUtil (value:Vector.<*>) :void {
// do stuff to/with the Vector
}
var someVector:Vector.<Number>;
someGenericVectorUtil(Vector.<*>(someVector));
^ it works. Also try with Array.
This is not an answer but more a long comment to #Lukasz's answer.
The problem with his answer is that you're actually creating a new Vector, so you need to return the Vector from someGenericVectorUtil and re-cast it. E.g. try:
var v:Vector.<int> = Vector.<int>([1,2,3]);
trace( v == Vector.<int>( Vector.<*>( v ) ) ); // traces false
That code just creates a simple Vector of ints, then compares it with a version of itself casted (first to *, then back to int). If you trace the Vectors out, they'll trace identical, but the actual Vectors references themselves aren't the same object. Thus if you have a utility function that modifies the Vector (e.g. a shuffle or randomise function), nothing will change.
E.g:
var v:Vector.<int> = Vector.<int>([1,2,3]);
trace( v ); // traces "1,2,3"
// shuffle() randomises the elements in a vector - this first call won't work
// as the cast creates a new vector
VectorUtil.shuffle( Vector.<*>( v ) );
trace( v ); // traces "1,2,3"
// we need to recast it back, and change shuffle() to return the vector
v = Vector.<int>( VectorUtil.shuffle( Vector.<*>( v ) ) );
trace( v ); // traces "3,1,2"
As you can see, it starts to get a bit ugly towards the end, and if you're keeping track of the Vector anywhere else, you'll need to update the references, but it's the only solution that I've found so far :S