helins.htm.grid — io.helins/htm 0.0.0-alpha0

Regular cartesian grids.

Glossary

capacity How many elements fit on a dimension, a portion of a grid, or a whole grid.

coordinate, coord Integer expression the unique location of an element in a dimension.

coordinates, coords Vector of coordinates expressing a unique location in a grid.

dimension, dim Always described by its capacity.

element Member of a grid, always has unique coordinates.

flat-index, f-index Any coordinates can be translated into a unique and corresponding 'f-indexbetween 0 (inclusive) andcapacity(exclusive). For instance, in a 2D 32x64 grid, the element with coordinates [4 10] would have af-index` of (+ (* 4 64) 10). It is like unfolding an N dimensional space into a single dimension.

grid Regular Cartesian grid partitioning a finite N dimensional space into a topology of elements with integer coordinates. Described by a vector of dimensions. A 2D 32x64 grid would be [32 64].

hypercube Vector of 2-tuples [coordinate capacity], one for every dimension, expressing a hypercube in a grid. A coordinate can be outside of the capacity of the corresponding grid dimension. Depending on the context, the hypercube would be truncated or wrapped (cf. wrapping).

n-dims Number of dimensions.

normal-coords coordinates normalized to fit between 0 and 1 (inclusive).

random-number-generator, rng No-arg function returning a random value between 0 (inclusive) and 1 (exclusive).

relative-coords coordinates in one grid always have relative coordinates in another grid. For instance, coordinates [1 1] in a [4 4] grid can be translated to coordinates [3 3] in a [10 10] grid which, proportionally, represents the same location.

relative-f-index Just like relative-coords, but for a flat-index.

wrapping Dimensions can behave in a cyclic manner. For instance, a coordinate of -2 on a dimension of capacity 6 would effectively be 4.

coords->f-index clj

(coords->f-index grid coords)

Translates coordinates to the corresponding flat-index in the given grid.

denormalize-coords clj

(denormalize-coords grid normal-coords)

Does the opposite of normalize-coords.

dim-ranges clj

(dim-ranges grid seq-coords)

Given a sequence of coordinates in a grid, returns a vector of [min-coord max-coord] for every dimension.

dim-span clj

(dim-span dim-ranges)

Given dim-ranges, computes the span for every dimension.

f-index->coords clj

(f-index->coords grid f-index)

Translates a flat-index to the corresponding coordinates in the given grid.

f-index->coords-hypercube clj

(f-index->coords-hypercube hypercube f-index)

Computes the coordinates of a flat-index within a hypercube.

grid-capacity clj

(grid-capacity grid)

Computes the capacity of a grid (ie. how many elements it represents).

hypercube* clj

(hypercube* grid radius coords-center)

Builds a hypercube in a grid from coordinates expressing its center.

hypercube->grid clj

(hypercube->grid hypercube)

Transforms a hypercube into a grid.

normalize-coords clj

(normalize-coords grid coords)

Normalizes coordinates to be between 0 and 1.

relative-coords clj

(relative-coords grid-1 grid-2 coords-2)

Maps coordinates in grid-2 to relative coordinates in grid-1.

relative-f-index clj

(relative-f-index grid-1 grid-2 f-index-2)

Like relative-coords but works with flat-indexes.

sample-grid clj

(sample-grid grid n-sample)

(sample-grid grid n-sample rng)

Samples n-sample random elements from a grid.

sample-hypercube clj

(sample-hypercube grid hypercube n-sample)

(sample-hypercube grid hypercube n-sample rng)

Sample n-sample input bits from a hypercube within a grid.

wrap-coords clj

(wrap-coords grid coords)

Cf. wrapping in glossary.