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/*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#ifndef __FN_MULTI_FUNCTION_HH__
#define __FN_MULTI_FUNCTION_HH__
/** \file
* \ingroup fn
*
* A `MultiFunction` encapsulates a function that is optimized for throughput (instead of latency).
* The throughput is optimized by always processing many elements at once, instead of each element
* separately. This is ideal for functions that are evaluated often (e.g. for every particle).
*
* By processing a lot of data at once, individual functions become easier to optimize for humans
* and for the compiler. Furthermore, performance profiles become easier to understand and show
* better where bottlenecks are.
*
* Every multi-function has a name and an ordered list of parameters. Parameters are used for input
* and output. In fact, there are three kinds of parameters: inputs, outputs and mutable (which is
* combination of input and output).
*
* To call a multi-function, one has to provide three things:
* - `MFParams`: This references the input and output arrays that the function works with. The
* arrays are not owned by MFParams.
* - `IndexMask`: An array of indices indicating which indices in the provided arrays should be
* touched/processed.
* - `MFContext`: Further information for the called function.
*
* A new multi-function is generally implemented as follows:
* 1. Create a new subclass of MultiFunction.
* 2. Implement a constructor that initialized the signature of the function.
* 3. Override the `call` function.
*/
#include "BLI_hash.hh"
#include "FN_multi_function_context.hh"
#include "FN_multi_function_params.hh"
namespace blender::fn {
class MultiFunction {
private:
MFSignature signature_;
public:
virtual ~MultiFunction()
{
}
virtual void call(IndexMask mask, MFParams params, MFContext context) const = 0;
virtual uint32_t hash() const
{
return DefaultHash<const MultiFunction *>{}(this);
}
virtual bool equals(const MultiFunction &UNUSED(other)) const
{
return false;
}
uint param_amount() const
{
return signature_.param_types.size();
}
IndexRange param_indices() const
{
return signature_.param_types.index_range();
}
MFParamType param_type(uint param_index) const
{
return signature_.param_types[param_index];
}
StringRefNull param_name(uint param_index) const
{
return signature_.param_names[param_index];
}
StringRefNull name() const
{
return signature_.function_name;
}
const MFSignature &signature() const
{
return signature_;
}
protected:
MFSignatureBuilder get_builder(std::string function_name)
{
signature_.function_name = std::move(function_name);
return MFSignatureBuilder(signature_);
}
};
inline MFParamsBuilder::MFParamsBuilder(const class MultiFunction &fn, uint min_array_size)
: MFParamsBuilder(fn.signature(), min_array_size)
{
}
extern const MultiFunction &dummy_multi_function;
} // namespace blender::fn
#endif /* __FN_MULTI_FUNCTION_HH__ */
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