Numy

Numy is a library to be used for scientific and technical computing.

Numy contains modules for:

• Linear Algebra. Numy has NIF wrapper around native LAPACK library.
• more not yet

Table of contents

• Example
• Comparison
• Installation

• Linear Algebra with LAPACK

  • BLAS
  • LAPACK

Example

See this example in LAPACK reference documentation.

iex(1)> a = Numy.Lapack.new_tensor([3,5])
iex(2)> Numy.Tz.assign(a, [
...(2)> [1,1,1],
...(2)> [2,3,4],
...(2)> [3,5,2],
...(2)> [4,2,5],
...(2)> [5,4,3]])
:ok
iex(3)> b = Numy.Lapack.new_tensor([2,5])
iex(4)> Numy.Tz.assign(b, [
...(4)> [-10,-3],
...(4)> [12,14],
...(4)> [14,12],
...(4)> [16,16],
...(4)> [18,16]])
:ok
iex(5)> Numy.Lapack.solve_lls(a,b)
0
iex(6)> solution = Numy.Lapack.data(b,2*3)
[1.9999999999999982, 0.9999999999999983, 0.9999999999999991, 0.9999999999999997,
 1.0000000000000024, 2.0000000000000018]
iex(7)> Numy.Float.close?(solution, [[2,1], [1,1], [1,2]])
true

Comparison

The closest to Numy project (that I am aware of) is Matrex. Matrex is using immutable binaries and NIF code is calling enif_make_binary to return a result (matrix). enif_make_binary allocates memory space for the new binary. Numy on other hand is using mutable NIF resources and can reuse already allocated memory to store the result inside the context of NIF module.

Installation

Ubuntu 18.04, sudo apt install liblapacke-dev gfortran.

The package can be installed by adding numy to your list of dependencies in mix.exs:

def deps do
  [
    {:numy, "~> 0.1.0"}
  ]
end

Linear Algebra with LAPACK

BLAS

See Quick Reference Guide to the BLAS.

BLAS Level 1

Wrapper function	Direct function	Description
generate_plane_rotation	blas_drotg

BLAS Level 2

BLAS Level 3

LAPACK

Wrapper function	Direct function	Description
solve_lls	lapack_dgels