When I download data to c++ code, I see that floating point data is rounded to only 2 decimal places.
I have tried declaring other doubles with more decimal digits and they can be printed fine.
Is there a way to change this in the interface?
Regards,
On further checking it seems that c++ can only download 7 digits(including the decimal) from kdb server.
So it can download 45.1799 or 5432.15.
Any way I can fix this?
On Wednesday, December 4, 2013 2:08:41 PM UTC+5:30, naveen sharma wrote:
When I download data to c++ code, I see that floating point data is rounded to only 2 decimal places.
I have tried declaring other doubles with more decimal digits and they can be printed fine.Is there a way to change this in the interface?
Regards,
If you are retrieving the binary representation of these floats, the only restriction is that of IEEE754, which is the same for c/c++. If you are retrieving the stringified representation from the server, this is controlled by \P.
e.g.
q)22%7
3.142857
q)\P 0
q)22%7
3.1428571428571428
see http://code.kx.com/wiki/Reference/DisplayPrecision
maybe you can post some c code to show what you are doing?
K getTwoDat(servParams& spar, corrParams& cpar, string& dt)
{
string query = “corrTwoDat[” + cpar.symIn + “;” + to_string(cpar.interval) + “;” + dt + “]”;
K flip, result, columnNames, data, dtlist, procDict;
int row, col, nCols, nRows, handle=khp((S)(spar.host).c_str(), spar.port);
if(handle<0)printf(“Cannot connect\n”),exit(1);
else if(!handle)printf(“Wrong credentials\n”),exit(1);
result=k(handle,(S)query.c_str(),(K)0);
if(!result)
printf(“Network Error\n”),perror(“Network”),exit(1);
if(result->t==-128)
printf(“Server Error %s\n”,result->s),kclose(handle),exit(1);
kclose(handle);
if(result->t!=99&&result->t!=98) // accept table or dict
printf(“type %d\n”,result->t),r0(result),exit(1);
flip = kK(result->k)[1];
//flip = (result->k)[1];
//procDict = kK(
cout << kE(kK(flip)[35])[0] << “ss \n”;
return(flip);
}
This gets me the data. And as you can see the last line of the function prints just the two digits after decimal.
Another weird thing, Running \P 0 doesn’t change the display of 22%7. I still get only 7 digits after decimal.
does this help?
yes, type real will stringify to max[8;system"P"].
But I believe your issue here is with stringify of a single precision float in c++, not kdb+.
Thanks Charles!
It was just a display issue