imclab / ndarray-group

Wraps a group of ndarrays to return a single virtual ndarray using ndarray-proxy

ndarray-group

Wraps a group of ndarrays to return a single virtual ndarray using ndarray-proxy.

This should make it easy when dealing with chunked grids or voxel volumes to compare neighboring chunks.

Note however there is a performance hit in getting/setting values with this module. This could hopefully become less significant with code generation, but I'd like to wait until it's necessary before trying it.

Installation

npm install ndarray-group

Usage

group(dims, arrays)

dims specifies the dimensions of the group (by array as opposed to elements), so:

• [2, 2]: Takes four ndarrays and returns a wrapper twice as high and wide as each child.
• [3, 3, 3]: Takes 27 ndarrays, this time thrice as large.
• [2, 1, 1]: Takes 2 ndarrays, twice as large on the X axis but otherwise the same.

arrays is a list of ndarrays. Each array must be the same shape, and the list must be the correct length to fill the proxy ndarray.

Arrays should be sorted in ascending order by axis, e.g. [-1,-1], [0,-1], [1,-1], [-1,0], [0,0], [1,0]...

var group = require('ndarray-group')
var fill = require('ndarray-fill')
var chunks = []

for (var z = 0; z < 3; z += 1)
for (var y = 0; y < 3; y += 1)
for (var x = 0; x < 3; x += 1) {
  chunks.push(zeros([50, 50]))
}

var grouped = group([3, 3, 3], chunks)

fill(grouped, function(x, y, z) {
  return grouped.get(x, y, z) + 1
})