knn: function(points, queries, repeat) {
//Use ndarray-select to partially sort elements
var m = queries.length
var d = points[0].length
var n = points.length
var sel = ndselect.compile([1,0], false, "float64")
var pointArray = ndscratch.malloc([n, 2])
var weight = 0
var start = Date.now()
for(var i=0; i<repeat; ++i) {
for(var j=0; j<m; ++j) {
var q = queries[j]
var p = q[0]
var k = q[1]
for(var l=0; l<n; ++l) {
var d2 = 0.0
for(var a=0; a<d; ++a) {
d2 += Math.pow(p[a] - points[l][a], 2)
}
pointArray.set(l, 0, d2)
pointArray.set(l, 1, l)
}
sel(pointArray, k)
for(var l=0; l<k; ++l) {
weight += pointArray.get(l, 1)
}
}
}
var end = Date.now()
ndscratch.free(pointArray)
return [end-start, weight]
},
function createKDTree(points) {
var n, d, indexed
if(Array.isArray(points)) {
n = points.length
if(n === 0) {
return new KDTree(null, null, 0, 0)
}
d = points[0].length
indexed = ndarray(pool.mallocDouble(n*(d+1)), [n, d+1])
pack(points, indexed.hi(n, d))
} else {
n = points.shape[0]
d = points.shape[1]
//Round up data type size
var type = points.dtype
if(type === "int8" ||
type === "int16" ||
type === "int32" ) {
type = "int32"
} else if(type === "uint8" ||
type === "uint8_clamped" ||
type === "buffer" ||
type === "uint16" ||
type === "uint32") {
type = "uint32"
} else if(type === "float32") {
type = "float32"
} else {
type = "float64"
}
indexed = ndarray(pool.malloc(n*(d+1)), [n, d+1])
ops.assign(indexed.hi(n,d), points)
}
for(var i=0; i<n; ++i) {
indexed.set(i, d, i)
}
var pointArray = ndscratch.malloc([n, d], points.dtype)
var indexArray = pool.mallocInt32(n)
var pointer = 0
var pointData = pointArray.data
var arrayData = indexed.data
var l2_n = bits.log2(bits.nextPow2(n))
var sel_cmp = ndselect.compile(indexed.order, true, indexed.dtype)
//Walk tree in level order
var toVisit = [indexed]
while(pointer < n) {
var head = toVisit.shift()
var array = head
var nn = array.shape[0]|0
//Find median
if(nn > 1) {
var k = bits.log2(pointer+1)%d
var median
var n_2 = inorderTree.root(nn)
median = sel_cmp(array, n_2, function(a,b) {
return a.get(k) - b.get(k)
})
//Copy into new array
var pptr = pointArray.index(pointer, 0)
var mptr = median.offset
for(var i=0; i<d; ++i) {
pointData[pptr++] = arrayData[mptr++]
}
indexArray[pointer] = arrayData[mptr]
pointer += 1
//Queue new items
toVisit.push(array.hi(n_2))
if(nn > 2) {
toVisit.push(array.lo(n_2+1))
}
} else {
//Copy into new array
var mptr = array.offset
var pptr = pointArray.index(pointer, 0)
for(var i=0; i<d; ++i) {
pointData[pptr+i] = arrayData[mptr++]
}
indexArray[pointer] = arrayData[mptr]
pointer += 1
}
}
//Release indexed
pool.free(indexed.data)
return new KDTree(pointArray, indexArray, n, d)
}