find Maybe Haskell

Estoy tratando de hacer algo con

find :: (a -> Bool) -> a -> Maybe a
find p a
| p a = Just a
| otherwise = Nothing

Pero no se si esta del todo bien, el predicado podría ser cualquiera, no se como seria sin recursion

How to find non-trivial of a system of equation?

I have a system of four equations

 eqs4 := {(-5 + 2 c) E^(
     4 I c (Pi)) (E^(4 I c (Pi)) Subscript(x, 1) - Subscript(x, 
       4)) == (5 + 2 c) E^(
     12 I a c) (Subscript(x, 2) - 
       E^(4 I c (Pi)) Subscript(x, 3)), (-5 + 2 c) E^(
     6 I a c) (-E^(I b) + E^(6 I a c)) Subscript(x, 
     3) == (5 + 2 c) (1 - E^(I (b + 6 a c))) Subscript(x, 
     4), (-5 + 2 c) (-E^(2 I c (3 a + 2 (Pi))) + E^(
       I (b + 8 c (Pi)))) Subscript(x, 
     2) == (5 + 2 c) (-E^(-6 I c (a - 2 (Pi))) + E^(
       I (b + 8 c (Pi)))) Subscript(x, 1), 
   Subscript(x, 3) + 2 c (Subscript(x, 1) + Subscript(x, 3)) + 
     Subscript(x, 4) - Subscript(x, 
     1) - (5 + 2 c) Subscript(x, 2) == -2 c Subscript(x, 4)};

and I want to find the non-trivial solution of the system when $det=0$. I want to obtain $left{x_1,x_2,x_3,x_4right}$ in terms of other parameters.

Trying solve, I only obtain trivial solution zero:

Solve(eqs4, {Subscript(x, 1), Subscript(x, 2), Subscript(x, 3), 
   Subscript(x, 4)}) // 
 Simplify(#, 
   Assumptions -> 
    c (Element) Reals &&  c > 0  && b (Element) Reals &&  b > 0 && 
     a (Element) Reals &&  a > 0  && d (Element) Reals) &

Then, I try to ignore one of the equation and variables as follows

eqs3 := {(-5 + 2 c) E^(6 I a c) (-E^(I b) + E^(6 I a c)) Subscript(x, 
     3) == (5 + 2 c) (1 - E^(I (b + 6 a c))) Subscript(x, 
     4), (-5 + 2 c) (-E^(2 I c (3 a + 2 (Pi))) + E^(
       I (b + 8 c (Pi)))) Subscript(x, 
     2) == (5 + 2 c) (-E^(-6 I c (a - 2 (Pi))) + E^(
       I (b + 8 c (Pi)))) Subscript(x, 1), 
   Subscript(x, 3) + 2 c (Subscript(x, 1) + Subscript(x, 3)) + 
     Subscript(x, 4) - Subscript(x, 
     1) - (5 + 2 c) Subscript(x, 2) == -2 c Subscript(x, 4)};

and I get a solution

solution = 
  Solve(eqs3, {Subscript(x, 2), Subscript(x, 3), Subscript(x, 4)}) // 
   Simplify(#, 
     Assumptions -> 
      c (Element) Reals &&  c > 0  && b (Element) Reals &&  b > 0 && 
       a (Element) Reals &&  a > 0  && d (Element) Reals) &;

But when I try to verify this solution, one of them is not verified.

eqs4 /. solution // 
 Simplify(#, 
   Assumptions -> 
    c (Element) Reals &&  c > 0  && b (Element) Reals &&  b > 0 && 
     a (Element) Reals &&  a > 0  && d (Element) Reals) &

Does anybody have a suggestion on how I can find a solution of this system?

unity – GameObject.Find() can’t find object after loading the scene

I have 2 scenes in my project, MainMenu and Game.

Main Menu Image

Game Image

MainMenu scene contains 2 buttons, ‘Hide Black’ and ‘Hide White’. Game scene contains 2 panels, ‘Black’ and ‘White’. When the user clicks any of button from main menu, I wanna hide the corresponding panel in Game scene and also load the scene. This is the script for the same.

using UnityEngine;
using UnityEngine.SceneManagement;

public class MainMenu : MonoBehaviour {
    public void HideBlack() {
        SceneManager.LoadScene(1);
        GameObject black = GameObject.Find("Black");
        black.SetActive(false);
    }

    public void HideWhite() {
        SceneManager.LoadScene(1);
        GameObject white = GameObject.Find("White");
        white.SetActive(false);
    }
}

But it turns out that GameObject.Find can’t find the panels in my Game scene. I looked my forums for help but I find them confusing. What’s going on here?

online resources – How can I find out which places are most often frequented in a given area, preferably with a way to categorize places (e.g., restaurant or market)?

How can I find out which places are most often frequented in a given area, preferably with a way to categorize places (e.g., restaurant or market)? If country-specific, I’m looking for Thailand.

I first thought of looking at which location has the most reviews/ratings in a given area on Google Maps, but I’m told that using review counts on Google Maps a good approximation for the popularity of a location. What other solutions exist?


The motivations as a traveler to find out which places are most often frequented are well stated in https://www.top-rated.online/ (mirror):

When you travel to a new city, it takes time till you find your new
favorite place or visit what’s best here. You will want to visit the
best places there are, but it is so difficult to find them!

The most reviewed and top rated places are ones that you can trust.
But take everything with a grain of salt.

There are also many hidden gems that are extremely good, but are not
that popular. Also, always keep an eye on worst reviewed places and
tourist traps that you should avoid.

google play store – How to find previously installed apps after micro sdcard gone bad?

My micro sd card that was used to extend internal storage died. Now the apps I moved there are also gone. I don’t remember precisely what I had on the card but would like to reinstall all of them.

After doing factory reset on my phones, the system automatically installs my previously installed apps after logging in to my google account. Is there a way to access this list?

Find Out What is Affiliate Marketing| An Ultimate Guide for Marketers

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If you are a marketing professional then there are a lot of chances that you might have gone through the term affiliate marketing. In any case, you want to hear more before setting out on your affiliate marketing venture. Maybe you’re a blogger, website owner, SEO/SEM expert or any agency marketer. Or you might be considering to make money from home. In any case, affiliate advertising enables you to create easy revenue by suggesting, sharing or advancing the items or services of any business. The business itself, which is typically the maker of the item or administration, is otherwise called the Merchant The way that 16% of each and every online solicitation were credited with the impact of affiliate advancing in 2018 shows how much potential there is in this niche.

Full Article Source: https://www.temok.com/blog/what-is-affiliate-marketing/

 

c – Unable to find devices for udoo bolt v8 using OpenCL 1.2

I purchased an udoo bolt v8 and I want to try some parallel computing on it. I loaded it up with ubuntu 18.04. I think the OpenCL drivers are not on ubuntu on default, but I was unable to find the drivers on their site. https://www.amd.com/en/support

After installing amd ROCm, I was at least able to get clinfo to work, but the number of devices was shown to be zero.

Just to confirm, I wrote the program below and tried the different cl_device_types, getting the same answer.

There were multiple libOpenCL.so files provided by ROCm but I tried the ones found in both /opt/rocm/opencl/lib and /opt/rocm/lib and the results were the same.

#include <stdio.h>
#define CL_TARGET_OPENCL_VERSION 120
#include <CL/cl.h>

void cl_error(cl_int err, char *msg)
{
    if(err < 0)
    {
        printf("%s: ERROR CODE: %dn", msg, err);
        exit(0);
    }
}

int main()
{
    cl_int err;
    cl_uint nplatforms;

    err = clGetPlatformIDs(0, 0, &nplatforms);
    cl_error(err, "Unable to get platform IDs");

    printf("Number of platforms: %dn", nplatforms);
    
    cl_platform_id *platforms = (cl_platform_id *)malloc(sizeof(cl_platform_id) * nplatforms);

    err = clGetPlatformIDs(nplatforms, platforms, 0);
    cl_error(err, "Unable to get platform");

    //get the platform info
    size_t platform_strlen;
    err = clGetPlatformInfo(platforms(0), CL_PLATFORM_NAME, 0, 0, &platform_strlen);
    cl_error(err, "Unable to get platform info");
    
    char *platform_name = (char *)malloc(sizeof(char) * platform_strlen);
    err = clGetPlatformInfo(platforms(0), CL_PLATFORM_NAME, platform_strlen,platform_name, 0);

    printf("Platform: %sn", platform_name);    
    
    cl_uint num_devices;
    err = clGetDeviceIDs(platforms(0), CL_DEVICE_TYPE_DEFAULT, 1, 0, &num_devices);
    cl_error(err, "Unable to get number of devices");
    printf("Number of devices: %dn", num_devices);
    return 0;
}