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[tranviet <question178830@xxxxxxxxxxxxxxxxxxxxx>]

Question #178830 on Yade changed:
https://answers.launchpad.net/yade/+question/178830

tranviet proposed the following answer:
Hello wangxiaoliang,

I think we can build a new script for this. I have a file to generate
the packing with a given grain size distribution and a target porosity
but it was written in C++ (I did not use python at the time of one year
ago):

- First,you create a sphere with radius satisfy:

Real SphereGenerator::GenerateRadius(vector<Real>& sieveDimension, vector<Real>& percentPassed)
{
	
	typedef boost::random::lagged_fibonacci_01<Real, 48, 44497, 21034> lagged_fibonaccitemp;
	static lagged_fibonaccitemp rng;

  	static boost::uniform_real<> one_hundred(0.0,100.0);      
                                    
	static boost::variate_generator<lagged_fibonaccitemp, boost::uniform_real<> > random1(rng, one_hundred);           
  	Real random=random1();
	//cerr<<random<<"   ";
	int i;//,numberOfSieves=11;
	for (i=0;i!=numberOfSieves;++i)
	{
		if ((percentPassed[i]<random) && (percentPassed[i+1]>=random))
		{
			return (sieveDimension[i] + (random - percentPassed[i])*(sieveDimension[i+1]-sieveDimension[i])/(percentPassed[i+1]-percentPassed[i]))/2;///Fu, 2003;	
		}
	}
}

- Create spheres using this function until you get your target porosity,
calculated by:

Real CommonFunction::Porosity (MetaBody * ncb, Real& height, Real& BoxDimensionX, Real& BoxDimensionZ)
{
//	
	Real SphereVolume=0, radius=0;
        shared_ptr<BodyContainer>& bodies = ncb->bodies;
	BodyContainer::iterator bi    = bodies->begin();
	BodyContainer::iterator biEnd = bodies->end();
		
	for(  ; bi!=biEnd ; ++bi )
	{
	
		if((*bi)->isDynamic)
		{ 
			Sphere* sphere = YADE_CAST<Sphere*>((*bi)->geometricalModel.get());
			radius = sphere->radius;
			SphereVolume += 4.0/3.0*Mathr::PI*radius*radius*radius; 
		}
			
	}
	return (1-SphereVolume/(height*BoxDimensionX*BoxDimensionZ));
}

- You can place your generated spheres using any of the proposed methods
that are available in YADE.

Let me know if it can help you.

Cheers,

Viet

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