h value can be between 0<400 or even more, the below coding practise looks tedious...any better thought?
if (h<=40) {
nOfRound = 1;
} else if (40<h<=80) {
nOfRound = 2;
} else if (80<h<=120) {
nOfRound = 3;
} else if (120<h<=160) {
nOfRound = 4;
} else if (160<h<=200) {
nOfRound = 5;
} else {
qDebug() <<"too big";
nOfRound = 6;
}
Like this:
if (h <= 200) { nOfRound = h / 40 + 1; }
else { nOfRound = 6; qDebug << "too big"; }
(Note that division by a constant is actually pretty efficient, since it is typically implemented by a (fast) multiplication rather than a dynamic division.)
Related
I'm working on translation of some old MATLAB code to C++. I have noticed, that my custom function to calculate histogram that supposed to be equivalent to MATLAB [counts,centers]= hist(___) gives different results. I could not find a bug in my implementation, so I used MATLAB Coder to generate C++ function from MATLAB code and compare it to my C++ code. Here is a simple MATLAB function I used to generate C++ code:
function [counts, centers] = my_hist(values, bins)
[counts, centers] = hist(values, bins);
disp(centers);
disp(counts);
end
And a script to call it, so MATLAB can define inputs:
values = rand(1,1000);
bins = linspace(0.05, 0.95, 10);
[counts, centers] = my_hist(values, bins);
Based on the above, the Coder generates the function:
//
// File: my_hist.cpp
//
// MATLAB Coder version : 5.3
// C/C++ source code generated on : 17-Nov-2022 15:46:17
//
// Include Files
#include "my_hist.h"
#include "rt_nonfinite.h"
#include <algorithm>
#include <cmath>
#include <cstring>
#include <math.h>
// Function Definitions
//
// MY_HIST Summary of this function goes here
// Detailed explanation goes here
//
// Arguments : const double values[1000]
// const double bins[10]
// double counts[10]
// double centers[10]
// Return Type : void
//
void my_hist(const double values[1000], const double bins[10],
double counts[10], double centers[10])
{
double edges[11];
double nn[11];
double absx;
int k;
int low_i;
std::copy(&bins[0], &bins[10], ¢ers[0]);
for (k = 0; k < 9; k++) {
absx = bins[k];
edges[k + 1] = absx + (bins[k + 1] - absx) / 2.0;
}
edges[0] = rtMinusInf;
edges[10] = rtInf;
for (k = 0; k < 9; k++) {
double absx_tmp;
absx_tmp = edges[k + 1];
absx = std::abs(absx_tmp);
if ((!std::isinf(absx)) && (!std::isnan(absx))) {
if (absx <= 2.2250738585072014E-308) {
absx = 4.94065645841247E-324;
} else {
frexp(absx, &low_i);
absx = std::ldexp(1.0, low_i - 53);
}
} else {
absx = rtNaN;
}
edges[k + 1] = absx_tmp + absx;
}
std::memset(&nn[0], 0, 11U * sizeof(double));
low_i = 1;
int exitg1;
do {
exitg1 = 0;
if (low_i + 1 < 12) {
if (!(edges[low_i] >= edges[low_i - 1])) {
for (low_i = 0; low_i < 11; low_i++) {
nn[low_i] = rtNaN;
}
exitg1 = 1;
} else {
low_i++;
}
} else {
for (k = 0; k < 1000; k++) {
low_i = 0;
absx = values[k];
if (!std::isnan(absx)) {
if ((absx >= edges[0]) && (absx < edges[10])) {
int high_i;
int low_ip1;
low_i = 1;
low_ip1 = 2;
high_i = 11;
while (high_i > low_ip1) {
int mid_i;
mid_i = (low_i + high_i) >> 1;
if (values[k] >= edges[mid_i - 1]) {
low_i = mid_i;
low_ip1 = mid_i + 1;
} else {
high_i = mid_i;
}
}
}
if (values[k] == edges[10]) {
low_i = 11;
}
}
if (low_i > 0) {
nn[low_i - 1]++;
}
}
exitg1 = 1;
}
} while (exitg1 == 0);
std::copy(&nn[0], &nn[10], &counts[0]);
counts[9] += nn[10];
}
//
// File trailer for my_hist.cpp
//
// [EOF]
//
I don't understande what happens in this chunk of code and why it is done:
for (k = 0; k < 9; k++) {
double absx_tmp;
absx_tmp = edges[k + 1];
absx = std::abs(absx_tmp);
if ((!std::isinf(absx)) && (!std::isnan(absx))) {
if (absx <= 2.2250738585072014E-308) {
absx = 4.94065645841247E-324;
} else {
frexp(absx, &low_i);
absx = std::ldexp(1.0, low_i - 53);
}
} else {
absx = rtNaN;
}
edges[k + 1] = absx_tmp + absx;
}
The function shift the edges of bins, but how and why? I will be grateful for help and explanation!
That bit of code adds eps to each bin edge except the first and last.
It is hard to know why hist does this, they must be working around some edge case they discovered (presumably related to floating-point rounding errors), and figured this was the best or the easiest solution.
The other day, I wrote a console game of Tic-Tac-Toe in c++ for my son. He wanted me to add a computer, and I ended us using the minimax algorithm for the first time. I did some quick testing, but really just gave my laptop to my son as soon as it was printing stuff, who played with it for a couple minuets. I looked over his sholder once or twice, and noticed that it wasn't playing optimally, iv'e been trying to debug it, but I can't see where it goes wrong. I tried getting rid of alpha beta prunning, but that did not change anything.
For context, on the board the computer is -1, blank is 0, and the player is 1.
Here is the minimax function:
int minimax(int board[9], int depth, int alpha, int beta, bool isMaxizimaizingPlayer)
{
bool found = false;
for (int i = 0; i < 9; i++)
{
if (board[i] == 0)
{
found = true;
}
}
if (!found)
{
return eval(board);
}
if (depth == 0 || eval(board) != 0)
{
return eval(board);
}
if (isMaxizimaizingPlayer)
{
int maxEval = -2;
for (int spot = 0; spot < 9; spot++)
{
if (board[spot] == 0)
{
board[spot] = 1;
int e = minimax(board, depth - 1, alpha, beta, false);
if (e > maxEval)
{
maxEval = e;
}
//if (beta < alpha)
//{
// break;
//}
board[spot] = 0;
}
}
return maxEval;
}
else {
int minEval = 2;
for (int spot = 0; spot < 9; spot++)
{
if (board[spot] == 0)
{
board[spot] = -1;
int e = minimax(board, depth - 1, alpha, beta, true);
if (e < minEval)
{
minEval = e;
}
//if (beta < alpha)
//{
// break;
//}
board[spot] = 0;
}
}
return minEval;
}
}
To be compleate, here is my eval function:
int eval(int board[9])
{
/*horizontial*/
for (int i = 0; i < 3; i++)
{
if (board[i * 3] == board[i * 3 + 1] && board[i * 3 + 2] == board[i * 3] && board[i * 3] != 0)
{
return board[i * 3];
}
}
/*vertical*/
for (int i = 0; i < 3; i++)
{
if (board[i] == board[i + 3] && board[i] == board[i + 6] && board[i] != 0)
{
return board[i];
}
}
/*Both diags*/
if (board[4] != 0) {
if (board[0] == board[4] && board[0] == board[8])
{
return board[4];
}
if (board[2] == board[4] && board[4] == board[6])
{
return board[4];
}
}
return 0;
}
And here is the inital call:
int spot = 0;
int minEval = 2;
for (int i = 0; i < 9; i++)
{
if (board[i] == 0)
{
board[i] = -1;
int score = minimax(board, 3, -2, 2, false);
if (score < minEval) {
minEval = score;
spot = i;
}
board[i] = 0;
}
}
std::cout << "The computer went in spot " << spot + 1 << std::endl;
board[spot] = -1;
printBoard(board);
It looks like you only call minimax with a depth of three, so the algorithm will only look up to three moves ahead, if you want optimal play you need to set the depth to > 9, so that the agent is always looking ahead to the end of the game.
I've been trying to solve this problem (from school) for just about a week now. We're given two numbers, from -(10^100000) to +that.
Of course the simplest solution is to implement written addition, so that's what I did. I decided, that I would store the numbers as strings, using two functions:
int ti(char a) { // changes char to int
int output = a - 48;
return output;
}
char tc(int a) { // changes int to char
char output = a + 48;
return output;
}
This way I can store negative digits, like -2. With that in mind I implemented a toMinus function:
void toMinus(std::string &a) { // 123 -> -1 -2 -3
for (auto &x : a) {
x = tc(-ti(x));
}
}
I also created a changeSize function, which adds 0 to the beginning of the number until they are both their max size + 1 and removeZeros, which removes leading zeros:
void changeSize(std::string &a, std::string &b) {
size_t exp_size = std::max(a.size(), b.size()) + 2;
while (a.size() != exp_size) {
a = '0' + a;
}
while (b.size() != exp_size) {
b = '0' + b;
}
}
void removeZeros(std::string &a) {
int i = 0;
for (; i < a.size(); i++) {
if (a[i] != '0') {
break;
}
}
a.erase(0, i);
if (a.size() == 0) {
a = "0";
}
}
After all that, I created the main add() function:
std::string add(std::string &a, std::string &b) {
bool neg[2] = {false, false};
bool out_negative = false;
if (a[0] == '-') {
neg[0] = true;
a.erase(0, 1);
}
if (b[0] == '-') {
neg[1] = true;
b.erase(0, 1);
}
changeSize(a, b);
if (neg[0] && !(neg[1] && neg[0])) {
toMinus(a);
}
if(neg[1] && !(neg[1] && neg[0])) {
toMinus(b);
}
if (neg[1] && neg[0]) {
out_negative = true;
}
// Addition
for (int i = a.size() - 1; i > 0; i--) {
int _a = ti(a[i]);
int _b = ti(b[i]);
int out = _a + _b;
if (out >= 10) {
a[i - 1] += out / 10;
} else if (out < 0) {
if (abs(out) < 10) {
a[i - 1]--;
} else {
a[i - 1] += abs(out) / 10;
}
if (i != 1)
out += 10;
}
a[i] = tc(abs(out % 10));
}
if (ti(a[0]) == -1) { // Overflow
out_negative = true;
a[0] = '0';
a[1]--;
for (int i = 2; i < a.size(); i++) {
if (i == a.size() - 1) {
a[i] = tc(10 - ti(a[i]));
} else {
a[i] = tc(9 - ti(a[i]));
}
}
}
if (neg[0] && neg[1]) {
out_negative = true;
}
removeZeros(a);
if (out_negative) {
a = '-' + a;
}
return a;
}
This program works in most cases, although our school checker found that it doesn't - like instead of
-4400547114413430129608370706728634555709161366260921095898099024156859909714382493551072616612065064
it returned
-4400547114413430129608370706728634555709161366260921095698099024156859909714382493551072616612065064
I can't find what the problem is. Please help and thank you in advance.
Full code on pastebin
While I think your overall approach is totally reasonable for this problem, your implementation seems a bit too complicated. Trying to solve this myself, I came up with this:
#include <iostream>
#include <limits>
#include <random>
#include <string>
bool greater(const std::string& a, const std::string& b)
{
if (a.length() == b.length()) return a > b;
return a.length() > b.length();
}
std::string add(std::string a, std::string b)
{
std::string out;
bool aNeg = a[0] == '-';
if (aNeg) a.erase(0, 1);
bool bNeg = b[0] == '-';
if (bNeg) b.erase(0, 1);
bool resNeg = aNeg && bNeg;
if (aNeg ^ bNeg && (aNeg && greater(a, b) || bNeg && greater(b, a)))
{
resNeg = true;
std::swap(a, b);
}
int i = a.length() - 1;
int j = b.length() - 1;
int carry = 0;
while (i >= 0 || j >= 0)
{
const int digitA = (i >= 0) ? a[i] - '0' : 0;
const int digitB = (j >= 0) ? b[j] - '0' : 0;
const int sum = (aNeg == bNeg ? digitA + digitB : (bNeg ? digitA - digitB : digitB - digitA)) + carry;
carry = 0;
if (sum >= 10) carry = 1;
else if (sum < 0) carry = -1;
out = std::to_string((sum + 20) % 10) + out;
i--;
j--;
}
if (carry) out = '1' + out;
while (out[0] == '0') out.erase(0, 1);
if (resNeg) out = '-' + out;
return out;
}
void test()
{
std::random_device rd;
std::mt19937 gen(rd());
std::uniform_int_distribution<> dis(-std::numeric_limits<int32_t>::max(), std::numeric_limits<int32_t>::max());
for (int i = 0; i < 1000000; ++i)
{
const int64_t a = dis(gen);
const int64_t b = dis(gen);
const auto expected = std::to_string(a + b);
const auto actual = add(std::to_string(a), std::to_string(b));
if (actual != expected) {
std::cout << "mismatch expected: " << expected << std::endl;
std::cout << "mismatch actual : " << actual << std::endl;
std::cout << " a: " << a << std::endl;
std::cout << " b: " << b << std::endl;
}
}
}
int main()
{
test();
}
It can potentially be further optimized, but the main points are:
If the sign of both numbers is the same, we can do simple written addition. If both are negative, we simply prepend - at the end.
If the signs are different, we do written subtraction. If the minuend is greater than the subtrahend, there's no issue, we know that the result will be positive. If, however, the subtrahend is greater, we have to reformulate the problem. For example, 123 - 234 we would formulate as -(234 - 123). The inner part we can solve using regular written subtraction, after which we prepend -.
I test this with random numbers for which we can calculate the correct result using regular integer arithmetic. Since it doesn't fail for those, I'm pretty confident it also works correctly for larger inputs. An approach like this could also help you uncover cases where your implementation fails.
Other than that, I think you should use a known failing case with a debugger or simply print statements for the intermediate steps to see where it fails. The only small differences in the failing example you posted could point at some issue with handling a carry-over.
I'm designing and programming an elevator-like robot for a high school project. Could I possibly do anything to make this any simpler? Or better? I have attached a picture of my design that I made in AutoCAD Inventor with labels.
For those not familiar with RobotC or VEX (it is VERY similar to C and C++): the limit switches (limit1, limit2, ...) and bump switches (floor1, floor2, ...) are analog buttons and return a value of 0 if not pressed and 1 if pressed. The motor (mainMotor) rotates the gear which causes the mechanism to travel upwards on the slide. When the shaft sticking out the motor mechanism moves up and down, it presses limit switches and causes it to return a value of 1.
int callup [3];
int calldown [3];
int floorat[3];
int main ()
{
if (SensorValue[limit1] == 1)
{
floorat[0] = 1;
}
else
{
floorat[0] = 0;
}
if (SensorValue[limit2] == 1)
{
floorat[1] = 1;
}
else
{
floorat[1] = 0;
}
if (SensorValue[limit3] == 1)
{
floorat[2] = 1;
}
else
{
floorat[2] = 0;
}
if (SensorValue[floor1] == 1)
{
calldown[0] = 1;
SensorValue[LED1] = 1;
}
if (SensorValue[floor2] == 1 && floorat[2] == 1)
{
calldown[1] = 1;
SensorValue[LED2] = 1;
}
if (SensorValue[floor2] == 1 && floorat[0] == 1)
{
callup[1] = 1;
SensorValue[LED2] = 1;
}
if (SensorValue[floor3])
{
callup[2] = 1;
SensorValue[LED3] = 1;
}
motors ();
}
void motors ()
{
if (callup[2] == 1 && floorat[2] == 1)
{
int x = 1;
while (x < 3)
{
SensorValue[LED3] = 1;
wait(0.5);
SensorValue[LED3] = 0;
wait(0.5);
}
callup[2] = 0;
main ();
}
else if (callup[1] == 1 && floorat[1] == 1)
{
int x = 1;
while (x < 3)
{
SensorValue[LED2] = 1;
wait(0.5);
SensorValue[LED2] = 0;
wait(0.5);
}
callup[1] = 0;
main ();
}
else if (callup[0] == 1 && floorat[0] == 1)
{
int x = 1;
while (x < 3)
{
SensorValue[LED1] = 1;
wait(0.5);
SensorValue[LED1] = 0;
wait(0.5);
}
callup[0] = 0;
main ();
}
if (callup[2] == 1 && floorat[1] == 1 && calldown[0] == 0 || callup[2] == 1 && floorat[0] == 1 && callup[1] == 0)
{
startMotor(mainMotor, 60);
untilTouch(limit3);
stopMotor(mainMotor);
callup[2] = 0;
wait(1);
main ();
}
if (callup[1] == 1 && floorat[0] == 1)
{
startMotor(mainMotor, 60);
untilTouch(limit2);
stopMotor(mainMotor);
callup[1] = 0;
wait(1);
main();
}
if (calldown[1] == 1 && floorat[2] == 1)
{
startMotor(mainMotor, -60);
untilTouch(limit2);
stopMotor(mainMotor);
calldown[1] = 0;
wait(1);
main();
}
if (calldown[0] == 1 && floorat[2] == 1 && calldown[1] == 0 || calldown[0] == 1 && floorat[1] == 1)
{
startMotor(mainMotor, -60);
untilTouch(limit1);
stopMotor(mainMotor);
calldown[0] = 0;
wait(1);
main();
}
}
Although it shouldn't be a concern for this question, the 60 in the startMotor command is the speed of the motor, just to make it clearer.
Feel free to ask any more questions.
Let's define what are the states of an elevator at a given moment:
An elevator can go up, down, or be idle.
The elevator is at a given floor and go from one floor to the other when it trigger a switch:
Now, if we translate this into some pseudo code (which should be easily translated to RobotC) :
enum elevator_status = { idle, down, up };
int currentfloor; //1, 2, 3
switch(elevator_status)
{
case idle:
//we check if a button is pressed and possibly go up or down
if(SensorValue(floor1))
{
if(currentfloor > 1)
elevator_status = down;
}
else if(SensorValue(floor2))
{
if(currentfloor > 2)
elevator_status = down;
else if(currentfloor < 2)
elevator_status = up;
}
else if(SensorValue(floor3))
{
if(currentfloor < 3)
elevator_status = up;
}
break;
case up:
case down:
//we check if we trigger a floor switch and stop the elevator
if(SensorValue(limit1))
{
currentfloor = 1;
elevator_status = idle;
}
else if(SensorValue(limit2))
{
currentfloor = 2;
elevator_status = idle;
}
else if(SensorValue(limit3))
{
currentfloor = 3;
elevator_status = idle;
}
break;
}
//we set the speed of the motor
if(elevator_status == up)
{
set_motorstate(cw);
)
else if(elevator_status == down)
{
set_motorstate(ccw);
}
else if(elevator_status == idle)
{
set_motorstate(idle);
}
Note : in this code the elevator will only take care of new up and down floor calls when the elevator is idle. It does not store up and down call while it is moving and go there later. I do not know if it was a requirement for you.
I'm not familiar with RobotC or VEX, however I've noticed a certain amount of replicated operations that could be made into their own functions.
The following code snippets I would make into separate functions. So in the large function called motors you have the following set of operations:
int x = 1;
while (x < 3)
{
SensorValue[LED3] = 1;
wait(0.5);
SensorValue[LED3] = 0;
wait(0.5);
}
callup[2] = 0;
main ();
This is repeated with slightly different values.
Here I'd write a function like the following:
void adjust_sensors( size_t led, size_t level )
{
int x = 1;
while (x < 3)
{
SensorValue[led] = 1;
wait(0.5);
SensorValue[led] = 0;
wait(0.5);
}
callup[level] = 0;
main ();
}
You can do the same for the following code as well:
startMotor(mainMotor, 60);
untilTouch(limit3);
stopMotor(mainMotor);
callup[2] = 0;
wait(1);
main ();
Also it seems like the while loop will never end because the value of x never changes.
You also have a typo at the top when you declare:
int callown [2];
I presume you meant:
int calldown [2];
Would be good to add some comments to your code as well for clarity.
Hope this helps.
I could be way off, because I'm just a student with questions of my own but it looks like you may have made a mistake in your array sizes. For instance, when you declared:
int floorat[2];
This made the array size 2. Then you refer to 3 element locations in this array [0, 1, 2]. Also, can't you just use a regular integer, and assign it values 1, 2, or 3?
I would recommend redefining these varaibles as:
int callup;
int calldown;
int floorat;
Then you can avoid extra lines of code and simplify the if/else clauses to:
if (SensorValue[limit1] == 1)
{
floorat = 1;
}
if (SensorValue[limit2] == 1)
{
floorat = 2;
}
if (SensorValue[limit3] == 1)
{
floorat = 3;
}
I'm trying to make it where the character is in a tile and when they move up or down it moves to the next tile but I'm not sure how to do that. Right now, I have it set up where the character moves by pixels but I want it to move by 1 square.
The code right now is this, and it works, but it's glitchy in pixel mode. I believe if it was by blocks it might work better but I might change it anyway.
float spritewidth = sprite->stretchX;
float spriteheight = sprite->stretchY;
float bushwidth = bush->stretchX;
float bushheight = bush->stretchY;
//Basic border collision
if (sprite->x <= 0)
sprite->x = 0;
if (sprite->y <= 0)
sprite->y = 0;
if (sprite->x >= 455)
sprite->x = 455;
if (sprite->y >= 237)
sprite->y = 237;
if ( (sprite->x + spritewidth > bush->x) && (sprite->x < bush->x + bushwidth) && (sprite->y + spriteheight > bush->y) && (sprite->y < bush->y + bushheight) )
{
bushcol = 1;
}
else
{
bushcol = 0;
}
if (osl_keys->held.down)
{
if (bushcol == 1)
{
sprite->y = bush->y - spriteheight - 3;
bushcol = 0;
}
else
{
bushcol = 0;
sprite->y += 3;
}
}
if (osl_keys->held.up)
{
if (bushcol == 1)
{
sprite->y = bush->y + bushheight + 3;
bushcol = 0;
}
else
{
bushcol = 0;
sprite->y -= 3;
}
}
if (osl_keys->held.right)
{
if (bushcol == 1)
{
sprite->x = bush->x - spritewidth - 3;
bushcol = 0;
}
else
{
bushcol = 0;
sprite->x += 3;}
}
if (osl_keys->held.left)
{
if (bushcol == 1)
{
sprite->x = bush->x + bushwidth + 3;
bushcol = 0;
}
else
{
bushcol = 0;
sprite->x -= 3;
}
}
If you want the character to move one tile/square/block at a time, just move the sprite the number of pixels the tile is wide (or tall).
const int tile_width = 32; // or something
// and then
sprite->x += tile_width;