TFFTReal

[obiman]

Can anyone help me out with TFFTReal? I seem to be having problems with the Init() function.

The class states the following:

void Init(Option_t* flags, Int_t sign, const Int_t* kind)

Creates the fftw-plan

NOTE: input and output arrays are overwritten during initialisation,
so don’t set any points, before running this function!!!

1st parameter:
Possible flag_options:
“ES” (from “estimate”) - no time in preparing the transform, but probably sub-optimal
performance
“M” (from “measure”) - some time spend in finding the optimal way to do the transform
“P” (from “patient”) - more time spend in finding the optimal way to do the transform
“EX” (from “exhaustive”) - the most optimal way is found
This option should be chosen depending on how many transforms of the same size and
type are going to be done. Planning is only done once, for the first transform of this
size and type.
2nd parameter is dummy and doesn’t need to be specified
3rd parameter- transform kind for each dimension
4 different kinds of sine and cosine transforms are available
DCT-I - kind=0
DCT-II - kind=1
DCT-III - kind=2
DCT-IV - kind=3
DST-I - kind=4
DST-II - kind=5
DSTIII - kind=6
DSTIV - kind=7

I have been trying to run this as follows without success for the DCT-II option…

myTFFTReal->Init(“M”,+1,1);

error: invalid conversion from ‘int’ to ‘const Int_t*’
error: initializing argument 3 of ‘virtual void TFFTReal::Init(const Option_t*, Int_t, const Int_t*)’

I have also tried:

const Int_t knd = 1;
myTFFTReal->Init(“M”,+1,knd);

Clearly I may be doing something daft, but nevertheless it would be great to have a simple working example showing how these functions are declared.

Any help will be greatly appreciated!

[moneta]

Hi,

you need to pass a pointer to an int and not an int (this is because you can have different types for each dimension).
So in your case do

int kind[0] = 1;
myTFFTReal->Init("M",+1,kind);

Best Regards

Lorenzo