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	tAdded comments to contact search functions - sphere - GPU-based 3D discrete el…
	git clone git://src.adamsgaard.dk/sphere
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	---
	commit 56390347e098fcaf5b75899e0501283f20352d6f
	parent 0baac7842d73086a1e98f426473e9439a9af602e
	Author: Anders Damsgaard <[email protected]>
	Date: Mon, 3 Sep 2012 14:18:25 +0200

	Added comments to contact search functions

	Diffstat:
	M src/contactsearch.cuh \| 24 +++++++++++++++++++-----

	1 file changed, 19 insertions(+), 5 deletions(-)
	---
	diff --git a/src/contactsearch.cuh b/src/contactsearch.cuh
	t@@ -8,6 +8,7 @@
	// Calculate the distance modifier between a contact pair. The modifier
	// accounts for periodic boundaries. If the target cell lies outside
	// the grid, it returns -1.
	+// Function is called from overlapsInCell() and findContactsInCell().
	__device__ int findDistMod(int3* targetCell, Float3* distmod)
	{
	// Check whether x- and y boundaries are to be treated as periodic
	t@@ -74,8 +75,11 @@ __device__ int findDistMod(int3* targetCell, Float3* distmo…



	-// Find overlaps between particle no. 'idx' and particles in cell 'gridpos'
	+// Find overlaps between particle no. 'idx' and particles in cell 'gridpos'.
	+// Contacts are processed as soon as they are identified.
	+// Used for shearmodel=1, where contact history is not needed.
	// Kernel executed on device, and callable from device only.
	+// Function is called from interact().
	__device__ void overlapsInCell(int3 targetCell,
	unsigned int idx_a,
	Float4 x_a, Float radius_a,
	t@@ -171,9 +175,12 @@ __device__ void overlapsInCell(int3 targetCell,
	} // Check wether cell is empty end
	} // End of overlapsInCell(...)

	+
	// Find overlaps between particle no. 'idx' and particles in cell 'gridpos'
	-// Write the indexes of the overlaps in array contacts[]
	+// Write the indexes of the overlaps in array contacts[].
	+// Used for shearmodel=2, where bookkeeping of contact history is necessary.
	// Kernel executed on device, and callable from device only.
	+// Function is called from topology().
	__device__ void findContactsInCell(int3 targetCell,
	unsigned int idx_a,
	Float4 x_a, Float radius_a,
	t@@ -296,6 +303,7 @@ __device__ void findContactsInCell(int3 targetCell,
	// For a single particle:
	// Search for neighbors to particle 'idx' inside the 27 closest cells,
	// and save the contact pairs in global memory.
	+// Function is called from mainGPU loop.
	__global__ void topology(unsigned int* dev_cellStart,
	unsigned int* dev_cellEnd, // Input: Particles in…
	unsigned int* dev_gridParticleIndex, // Input: Unsort…
	t@@ -341,10 +349,16 @@ __global__ void topology(unsigned int* dev_cellStart,


	// For a single particle:
	-// Search for neighbors to particle 'idx' inside the 27 closest cells,
	-// and compute the resulting normal- and shear force on it.
	-// Collide with top- and bottom walls, save resulting force on upper wall.
	+// If shearmodel=1:
	+// Search for neighbors to particle 'idx' inside the 27 closest cells,
	+// and compute the resulting force and torque on it.
	+// If shearmodel=2:
	+// Process contacts saved in dev_contacts by topology(), and compute
	+// the resulting force and torque on it.
	+// For all shearmodels:
	+// Collide with top- and bottom walls, save resulting force on upper wall.
	// Kernel is executed on device, and is callable from host only.
	+// Function is called from mainGPU loop.
	__global__ void interact(unsigned int* dev_gridParticleIndex, // Input: Unsort…
	unsigned int* dev_cellStart,
	unsigned int* dev_cellEnd,