Feature #1768
Investigate whether we can interface GammaLib with NumPy
| Status: | In Progress | Start date: | 04/18/2016 | ||
|---|---|---|---|---|---|
| Priority: | Normal | Due date: | |||
| Assigned To: |  Knödlseder Jürgen | % Done: | 50% | ||
| Category: | - | ||||
| Target version: | - | ||||
| Duration: |
Description
Following discussions with Christoph, it would be useful to interface GammaLib with NumPy. NumPy is pretty standard in the Python community to handle ndarrays, and it could be useful for users that want to dive deeply into the internal working of the library to access data in that format.
However, since NumPy is not part of the Python standard library we want (at least for the moment) to keep the NumPy interface as an optional dependency. We have to see then how this evolves over time.
So this feature is about investigating how the interfacing with NumPy can be done properly / best.
I know that there is a NumPy swig interface, and maybe this can be simply added to the actual code using the appropriate swig typemaps / typechecks. It needs to be investigate how this can be done optionally (probably needs a NumPy detection step during configuration).
There is also the possibility (which I guess Christoph won’t like in a first place ) to implement ndarrays in GammaLib, and to interface these with NumPy. This would be the GammaLibonic way. I know that some LSST guy wrote a ndarray C++ package that is compatible with NumPy, maybe this can be adapted? See: https://github.com/lsst/ndarray and https://github.com/ndarray/ndarray (only the first is GPL3, the other is BSD license). The advantage of this approach is that we gradually could use the GammaLib ndarray to store stuff (maps, data, etc.), which then would make the information immediately available in the right format to NumPy. In that way we could both support NumPy and keep the formal independency to it.
Recurrence
No recurrence.
Related issues
History
#1
Updated by Knödlseder Jürgen over 7 years ago
- Related to Action #1731: Use low-level FFT classes to implement GSkyMap smoothing added
#2
Updated by Knödlseder Jürgen over 7 years ago
Here is a possible layout of the class:
class GNdarray : public GBase {
friend GNdarray sin(const GNdarray& array);
friend GNdarray cos(const GNdarray& array);
friend GNdarray tan(const GNdarray& array);
...
public:
GNdarray(void);
GNdarray(const int& nx);
GNdarray(const int& nx, const int& ny);
GNdarray(const int& nx, const int& ny, const int& nz);
GNdarray(const std::vector<int>& n);
...
double& operator()(const int& ix);
double& operator()(const int& ix, const int& iy);
double& operator()(const int& ix, const int& iy, const int& iz);
double& operator()(const std::vector<int>& i);
...
void clear(void);
GNdarray* clone(void) const;
std::string classname(void) const;
int size(void) const;
double& at(const int& ix);
double& at(const int& ix, const int& iy);
double& at(const int& ix, const int& iy, const int& iz);
double& at(const std::vector<int>& i);
const std::vector<int>& shape(void) const;
void shape(const std::vector<int>& shape);
...
protected:
std::vector<int> m_shape;
std::vector<int> m_strides;
std::vector<double> m_data;
};
#3
Updated by Knödlseder Jürgen over 7 years ago
- Status changed from New to In Progress
- Assigned To set to Knödlseder Jürgen
- Target version set to 1.2.0
- % Done changed from 0 to 50
An initial version of this class has been implemented.
Next step is to see whether the class is useable by the FFT class.
#4
Updated by Knödlseder Jürgen about 7 years ago
- Target version deleted (
1.2.0)