Return index of closest point for compute_gdist()

[GostInShell]

If I get this right, when more than one source_indices are given, the function compute_gdist() will return the distance of a target to the closest source. Can the function compute_gdist() also return the index of the closest source? Are there any interfaces in the orignal C++ code?

[ayan-b]

Hi @GostInShell, the cython code doesn't provide the index as of now, however, you can use GeodesicAlgorithmExact::best_source method to obtain the index.

tvb-gdist/geodesic_library/geodesic_algorithm_exact.h

Lines 1175 to 1191 in 943c0e0

	/*
	Quickly find what source this point belongs to and what is the distance to this source
	*/
	inline unsigned GeodesicAlgorithmExact::best_source(SurfacePoint& point,
	double& best_source_distance)
	{
	double best_interval_position;
	unsigned best_source_index;
	best_first_interval(point,
	best_source_distance,
	best_interval_position,
	best_source_index);
	return best_source_index;
	}

If you want to obtain the values from the cython code, first change compute_gdist_impl method here:

tvb-gdist/geodesic_library/geodesic_utils.h

Line 5 in 943c0e0

std::vector<double> compute_gdist_impl(

tvb-gdist/geodesic_library/geodesic_utils.h

Lines 33 to 35 in 943c0e0

	for (unsigned k = 0; k < stop_points.size(); ++k) {
	algorithm.best_source(stop_points[k], distances[k]);
	}

Then, update the compute_gdist method here:

tvb-gdist/gdist.pyx

Line 119 in 943c0e0

def compute_gdist(numpy.ndarray[numpy.float64_t, ndim=2] vertices,

Make sure to update the method signature as well:

tvb-gdist/gdist.pyx

Lines 82 to 83 in 943c0e0

	cdef extern from "geodesic_utils.h":
	vector[double] compute_gdist_impl(vector[double], vector[unsigned], vector[unsigned], vector[unsigned], double, bool, bool)

[GostInShell]

Hi, @ayan-b! Thank U so much for the detailed reply! Feeling condifent to implement this by following your instructions!