I'm using ta-lib c++ library to calculate MACD, but the result is totally different from what the website shows,
the real MACD is [444.39, 505.05, 248.02, -232.33, 100.39, -13.18],
but my result is [282.10, -74.12, -211.27, -460.82, -850.86]
I have set all the MAType to TA_MAType_EMA, but it makes no sense
#include <iostream>
#include <cassert>
#include <ta-lib/ta_libc.h>
using namespace std;
int main()
{
// init ta-lib context
TA_RetCode retcode;
retcode = TA_Initialize();
assert(retcode == TA_SUCCESS);
// comput moving average price
TA_Real close_price_array[100] = { 37924.41, 40849.89, 37952.37, 36564.58, 36844.22, 34719.71, 33156.65, 32858.22,
34212.01, 37118.35, 31924.17, 30327.18, 31757.38, 34459.95, 31952.8 , 31876.57,
32457.32, 31392.34, 34183.43, 37328.12, 36408.31, 35732.04, 37460.76, 35627.27,
39551.87, 34677.01, 33834.78, 31580.01, 39674.77, 40513.11, 40829.87, 38950.0 ,
34555.33, 32091.45, 31737.83, 33506.67, 31695.17, 29190.91, 28779.14, 28153.95,
26617.04, 26911.93, 27360.51, 25625.24, 24019.43, 23230.15, 23450.3 , 23341.65,
23099.56, 23873.04, 23551.1 , 22553.6 , 23329.31, 20659.69, 19406.28, 19198.7 ,
19215.36, 18401.98, 18106.72, 18134.91, 18347.36, 18806.82, 19213.0 , 19126.33,
19107.67, 18945.51, 19533.84, 18891.06, 19265.5 , 19306.92, 18116.34, 17505.0 ,
16502.76, 16905.43, 19129.39, 19358.42, 18269.55, 18294.73, 18784.06, 18655.81,
18046.78, 17871.06, 17318.57, 16450.98, 16026.15, 15950.15, 16098.79, 16122.33,
15666.22, 15168.03, 15004.24, 15354.6 , 15342.63, 15411.23, 15077.18, 13911.95,
13708.92, 13492.15, 13797.96, 13854.39 };
TA_Real *p = close_price_array;
cout.precision(8);
TA_Integer out_begin = 0;
TA_Integer out_nb_element = 0;
TA_Real outMACD[100] = { 0 };
TA_Real outMACDSignal[100] = { 0 };
TA_Real outMACDHist[100] = { 0 };
retcode = TA_MACDEXT(0, 99,
&close_price_array[0],
12, TA_MAType_EMA ,
26, TA_MAType_EMA ,
9, TA_MAType_EMA ,
&out_begin, &out_nb_element,
outMACD, outMACDSignal, outMACDHist);
assert(retcode == TA_SUCCESS);
cout << "out_begin_index: " << out_begin << endl;
cout << "out_nb_element: " << out_nb_element << endl;
cout << "outMACD array: " << endl;
for (auto &i : outMACD)
cout << i << " ";
cout << endl;
cout << "outMACDSignal array: " << endl;
for (auto &i : outMACDSignal)
cout << i << " ";
cout << endl;
cout << "outMACDSignal array: " << endl;
for (auto &i : outMACDHist)
cout << i << " ";
cout << endl;
retcode = TA_Shutdown();
assert(retcode == TA_SUCCESS);
return 0;
}
enter image description here
[After comparing TA-lib results with Excel calculations]: In your excel the 12-day EMA is calculated from the 1st day and its first value is the average on 12th day (8/13/2020) and the 26-day EMA is calculated from 1st day and first value is average on 26th day (26/13/2020). TA-Lib postpones the 12 day EMA calculation start to get its first value on the same day as first value of 26-day EMA. That means 12-day EMA is calculated from 8/16/2020 and it's first value is the average on (26/13/2020) as it's in 26-day EMA. So to adjust your excel to TA-Lib results you need to copy formula =AVERAGE(B19:B30) into the cell C30.
Another note is that TA-Lib's MACD outputs 3 arrays at once: macd, signal, histogram. And thus TA-Lib starts the output at the point it got meaningful values for all 3 result arrays. Thus you're getting result starting not from the point where 26-day EMA can be calculated, but from the point where Signal can be calculated (8 days later). So you shall compare talib_macd[1] with excel starting from cell E38 instead of E30.
For some unknown reason this simple code runs, does what it's expected to do and then crashes the run. I am using NetBeans IDE, which overlapped my arrays before (tends to be buggy), so I was wondering if someone gets the same error - that would mean I certainly have to change the IDE environment.
#include <iostream>
using namespace std;
int main ()
{
int first[4][4];
for (int a = 0; a < 5; a++)
{
for (int b = 0; b < 5;b++)
{
cout << a << " " << b << " ";
if (first [a][b] != 0)
{
first[a][b] = 0;
}
cout << first[a][b] << " ";
}
cout << endl << endl << endl;
}
return 0;
};
here you are declearing a array with 4 indexes.In c/c++ index number starts at 0.
In your code you are saying :
int first[4][4];
that means indexs are : 0 1 2 3.Array length or total index are 4.
But in for loop you are saying
for (int a = 0; a < 5; a++) {
....
}
so you are trying to access index number 0 1 2 3 4 respectively.But remember you don't have index number 4.That is why it should give array index out of bound error.
Also at the end of main function you are using a semicolon.remove that
main () {
....
};
Hope this solves the problem.From next time Please try to provide details about the errors your IDE is giving you as it will be easier for the people who are giving answer.
Declaring the Mat image, and assigning values.
Mat magnitude = Mat(gradient_columns.cols, gradient_columns.rows, CV_64FC1);
for(int i = 0; i < gradient_columns.cols; i++)
{
for(int j = 0; j < gradient_columns.rows; j++)
{
magnitude.at<double>(Point(i,j)) = (double)hypot(gradient_columns.at<double>(Point(i,j)), gradient_rows.at<double>(Point(i,j)));
}
}
Printing the above Mat:
cout << "M = " << magnitude << endl;
Result:
M = [0, 0, 0.1257399049164523, 12.36316814720732, 12.50461780753356, 0.2674320707434279, 10.39230484541326, 12.03299037437945, 5.430256687374658,
12.03299037437945, 4.684492386402418, 4.72934192083521, 12.16431633381293, 5.397674732957373, 12.30042244512288, 10.25834261322606, 0.3944487245360109,
12.16431633381293, 11.84297951775486, 12.44187210544911, 12.10132213098092,
0.4088817310696626, 10.15078660267586, 12.09573607646389, 2.076275433221507, 0, 0.1257399049164523, 0, 0.1257399049164523, 0;
.....
.....]
The above result is completely correct and as expected.
However if I try to print individual values I get wrong results:
cout.precision(20);
cout << "CHANNELS: " << magnitude.channels() << endl;
cout << magnitude.at<double>(Point(0, 2)) << endl;
cout << magnitude.at<double>(Point(0, 3)) << endl;
cout << magnitude.at<double>(Point(0, 4)) << endl;
cout << magnitude.at<double>(Point(0, 5)) << endl;
Result | Actual Value:
CHANNELS: 1
0.062870 | 0.1257399049164523,
0.000000 | 12.36316814720732,
0.031404 | 12.50461780753356,
0.000000 | 0.2674320707434279
I understand its some data type conversion issue, but if anyone can suggest any solution?
Thanks.
I believe that there is nothing wrong with your matrix. You are just not printing what you think you are.
When writing magnitude.at<double>(Point(0,2)), you're not printing the number in line 0 and column 2 as you expected, but the number in line 2 and column 0. Try to write magnitude.at<double>(0,2) instead.
For those who are having a similar issue and #Sunreef's answer does not work, check if you are accidentally using mat.at<float>(_,_) instead of mat.at<double>(_,_)
I've been assigned a project to determine the square root of a number without using division or the math.h library. Upon doing my own research I've decided to tackle the problem by using the bisection method. I used the pseudo code portion from the Bisection Wikipedia page:
https://en.wikipedia.org/wiki/Bisection_method#Example:_Finding_the_root_of_a_polynomial
to setup the algorithm.
My Code
#include <iostream>
#include <cmath>
#include <stdlib.h>
using namespace std;
void __attribute__((weak)) check(double alt_sqrt(double));
//default check function - definition may be changed - will not be graded
void __attribute__((weak)) check(double alt_sqrt(double))
{
if(alt_sqrt(123456789.0) == sqrt(123456789.0))cout << "PASS\n";
else cout << "FAIL\n";
return;
}
//change this definition - will be graded by a different check function
double my_sqrt(double x)
{
int i = 0;
double a = 0.0; // Lower Bound
double b = x + 1; // Upper Bound
double c = 0.0; // Guess for square root
double error = 0.00001;
double fc = 0.0;
while(i < 10000)
{
c = (a+b)*0.5;
fc = c * c - x;
if(abs(fc) < error || (b-a)*0.5 < error) // Check for solution
{
cout << "Square root is: " << c << endl;
break;
}
if(fc < 0) // Setup new interval
{
a = c;
cout << "a is: " << a << endl;
}
else b = c;
cout << "b is: " << b << endl;
i++;
}
return c;
}
//Do not change this function
int main()
{
check(my_sqrt);
return 0;
}
The output I am currently getting for my professor's test case in main is
Square root is: 1.23457e+08
FAIL
When the correct output should be
Square root is: 11,111.11106
PASS
I believe that I am going wrong in the way that I setup my new intervals. My thinking is that if the difference between the two values is negative, then I need to push the lower bound up, and if the difference is positive, then I need to bump the upper bound down.
I would appreciate any advice y'all could give me. Thank you for your time.
The condition fb - fa < 0 is wrong because ignoring floating-point errors, fa < fb, which is a * a - x < b * b < x will be always true for 0 <= a < b.
Changing the condition to fc < 0 improved the accuracy, but unfortunately this improvement coundl't make the program print "PASS". To improve the accuracy to have the program print "PASS", delete the harmful breaking part
if(abs(fc) < error || (b-a)*0.5 < error) // Check for solution
{
cout << "Square root is: " << c << endl;
break;
}
Removing this harmful breaking and adding the line
cout << "Square root is: " << c << endl;
just before
return c;
gave me
Square root is: 11111.1
PASS
but unfortunately this is not what you want.
To have what you want printed,
#include <iomanip>
should be added and the printing part should be
std::cout.imbue(std::locale(""));
cout << fixed << setprecision(5) << "Square root is: " << c << endl;
I wrote a function within my code that should create some sort of matrices. It is fine when the size is small, but when it gets bigger, it crashes at the middle of this function without giving any information. I did that with both debug and release mode and same thing happened. Any idea on what can be wrong? Someone suggested me it could be buffer overrun.
In this function when kl.mechelms get bigger than a certain number, it crashes. The following code uses a function and gets a 3 by 3 matrix and stores it in kl.scoff which size is [3][3][kl.mechelms][kl.mechelms]. The problem happens when kl.mechelms are like bigger than 7000, but we need far more than that for our code.
Could the function Calc_3D which I use within this part cause the problem? I think it shouldn't since it just reads some values.
for (int z = 0;z<3;z++) {
for (int q = 0;q<3;q++) {
kl.scofsarr[z][q] = new double *[kl.mechelms];
}
}
for (int i = 0;i<kl.mechelms;i++) {
cout << "element " << i << "of " << kl.mechelms << endl;
kl.comments << "element " << i << "of " << kl.mechelms << endl;
for (int z = 0;z<3;z++) {
for (int q = 0;q<3;q++) {
kl.scofsarr[z][q][i] = new double[kl.mechelms];
}
}
for (int j = 0;j<kl.mechelms;j++) {
Calc_3D(i,j, kl.elmx[j], kl.elmy[j], kl.elmz[j], kl.anglemat[j], kl.dip[j], kl.elmx[i],kl.elmy[i],kl.elmz[i],
kl.elma[i],kl.rectza,kl.anglemat[i],kl.dip[i], kl.G, kl.v, kl.scofs, kl.rdepth);
for (int z = 0;z<3;z++) {
for (int q = 0;q<3;q++) {
kl.scofsarr[z][q][i][j] = kl.scofs[z][q];
}
}
}
}