Hello,
I would like to try the example program "xcorrel.cpp" which calls the function "correl". I copied the main from the NR directory I have bought and I have included some header files (copied in the same directory of my main).
When I compile with the command g++ I find this errors:

#include <iostream>
#include <iomanip>
#include "nr3.h"
#include "fourier.h"
#include "correl.h"
using namespace std;

int main()
{
const int N=64;
int i,j;
DP cmp;
Vec_DP data1(N),data2(N),ans(N);

for (i=0;i<N;i++) {
if ((i > N/2-N/8-1) && (i < N/2+N/8-1))
data1[i]=1.0;
else
data1[i]=0.0;
data2[i]=data1[i];
}
NR::correl(data1,data2,ans);
// Calculate directly
cout << setw(3) << "n" << setw(15) << "CORREL";
cout << setw(19) << "direct calc." << endl;
cout << fixed << setprecision(6);
for (i=0;i<=16;i++) {
cmp=0.0;
for (j=0;j<N;j++)
cmp += data1[((i+j) % N)]*data2[j];
cout << setw(3) << i << setw(16) << ans[i];
cout << setw(16) << cmp << endl;
}
return 0;
}

esercizio.cpp: In function 'int main()':
esercizio.cpp:12: error: 'DP' was not declared in this scope
esercizio.cpp:12: error: expected `;' before 'cmp'
esercizio.cpp:13: error: 'Vec_DP' was not declared in this scope
esercizio.cpp:13: error: expected `;' before 'data1'
esercizio.cpp:17: error: 'data1' was not declared in this scope
esercizio.cpp:19: error: 'data1' was not declared in this scope
esercizio.cpp:20: error: 'data2' was not declared in this scope
esercizio.cpp:20: error: 'data1' was not declared in this scope
esercizio.cpp:22: error: 'NR' has not been declared
esercizio.cpp:22: error: 'data1' was not declared in this scope
esercizio.cpp:22: error: 'data2' was not declared in this scope
esercizio.cpp:22: error: 'ans' was not declared in this scope
esercizio.cpp:28: error: 'cmp' was not declared in this scope

Thank you for your attention,
Fluo

...I would like to try the example program "xcorrel.cpp" ...

In NR3 it's Doub and VecDoub, not DP and Vec_DP.

Also, you don't use the NR:: namespace any more.

Note that nr3.h includes almost all of the C++ header files that you (probably) need, and it also does the namespace std thing.

Bottom line:


#include "nr3.h"
#include "fourier.h"
#include "correl.h"

int main()
{
const int N = 64;
int i, j;
Doub cmp;
VecDoub data1(N), data2(N), ans(N);

for (i = 0; i < N; i++) {
if ((i > N / 2 - N / 8 - 1) && (i < N / 2 + N / 8 - 1)) {
data1[i] = 1.0;
}
else {
data1[i] = 0.0;
}
data2[i] = data1[i];
}
correl(data1, data2, ans);

// Calculate directly
cout << setw(3) << "n" << setw(15) << "CORREL";
cout << setw(19) << "direct calc." << endl;
cout << fixed << setprecision(6);
for (i = 0; i <= 16; i++) {
cmp = 0.0;
for (j = 0; j < N; j++) {
cmp += data1[((i + j) % N)] * data2[j];
}
cout << setw(3) << i << setw(16) << ans[i];
cout << setw(16) << cmp << endl;
}
return 0;
}


Output:

n CORREL direct calc.
0 15.000000 15.000000
1 14.000000 14.000000
2 13.000000 13.000000
3 12.000000 12.000000
4 11.000000 11.000000
5 10.000000 10.000000
6 9.000000 9.000000
7 8.000000 8.000000
8 7.000000 7.000000
9 6.000000 6.000000
10 5.000000 5.000000
11 4.000000 4.000000
12 3.000000 3.000000
13 2.000000 2.000000
14 1.000000 1.000000
15 0.000000 0.000000
16 -0.000000 0.000000

thank you!