Initial commit

.gitignore

@@ -0,0 +1,2 @@
+*~
+.stack-work

LICENSE

@@ -0,0 +1,30 @@
+Copyright Dimitri Lozeve (c) 2017
+
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+
+    * Redistributions in binary form must reproduce the above
+      copyright notice, this list of conditions and the following
+      disclaimer in the documentation and/or other materials provided
+      with the distribution.
+
+    * Neither the name of Author name here nor the names of other
+      contributors may be used to endorse or promote products derived
+      from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

README.md

@@ -0,0 +1 @@
+# orbit

Setup.hs

@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain

app/Main.hs

@@ -0,0 +1,6 @@
+module Main where
+
+import Lib
+
+main :: IO ()
+main = putStrLn "Hello"

orbit.cabal

@@ -0,0 +1,42 @@
+name:                orbit
+version:             0.1.0.0
+-- synopsis:
+-- description:
+homepage:            https://github.com/dlozeve/orbit#readme
+license:             BSD3
+license-file:        LICENSE
+author:              Dimitri Lozeve
+maintainer:          dimitri.lozeve@gmail.com
+copyright:           2017 Dimitri Lozeve
+category:            Science
+build-type:          Simple
+extra-source-files:  README.md
+cabal-version:       >=1.10
+
+library
+  hs-source-dirs:      src
+  exposed-modules:     Lib
+  build-depends:       base >= 4.7 && < 5
+                     , linear
+  default-language:    Haskell2010
+
+executable orbit-exe
+  hs-source-dirs:      app
+  main-is:             Main.hs
+  ghc-options:         -threaded -rtsopts -with-rtsopts=-N
+  build-depends:       base
+                     , orbit
+  default-language:    Haskell2010
+
+test-suite orbit-test
+  type:                exitcode-stdio-1.0
+  hs-source-dirs:      test
+  main-is:             Spec.hs
+  build-depends:       base
+                     , orbit
+  ghc-options:         -threaded -rtsopts -with-rtsopts=-N
+  default-language:    Haskell2010
+
+source-repository head
+  type:     git
+  location: https://github.com/githubuser/orbit

src/Lib.hs

@@ -0,0 +1,81 @@
+module Lib (
+  gravity,
+  Body,
+  bodyDistance,
+  field,
+  acceleration,
+  update,
+  b1, b2, b3
+  ) where
+
+import Linear.Vector
+import Linear.V3
+import Linear.Affine
+import Linear.Metric
+
+--------------------------------------------------------------------------------
+-- CONSTANTS
+--------------------------------------------------------------------------------
+
+-- Gravitational constant [m^3 kg^-1 s^-2]
+gravity :: Double
+gravity = 6.67408e-11
+
+--------------------------------------------------------------------------------
+-- BODY TYPE
+--------------------------------------------------------------------------------
+
+-- Body
+data Body = Body {
+  bodyMass :: Double,
+  bodyPosition :: Point V3 Double,
+  bodySpeed :: V3 Double
+  } deriving (Show, Eq)
+
+
+-- Distance between two bodies
+bodyDistance :: Body -> Body -> Double
+bodyDistance body1 body2 =
+  distance (bodyPosition body1) (bodyPosition body2)
+
+
+--------------------------------------------------------------------------------
+-- GRAVITY FORCE
+--------------------------------------------------------------------------------
+
+-- Field created by a body on a certain position
+field :: Body -> Point V3 Double -> V3 Double
+field body pos =
+  unP $ (gravity * m / r**2) *^ (normalize vec)
+  where m = bodyMass body
+        vec = (bodyPosition body) - pos
+        r = norm vec
+
+-- Acceleration given to a body by its neighbours
+acceleration :: Body -> [Body] -> V3 Double
+acceleration body = foldr f (fromInteger 0)
+  where f neighbour acc =
+          acc + field neighbour (bodyPosition body)
+
+
+--------------------------------------------------------------------------------
+-- SIMULATION
+--------------------------------------------------------------------------------
+
+-- Update speed and position with using a timestep dt
+update :: Double -> Body -> [Body] -> Body
+update dt (Body m pos speed) neighbours =
+  Body m newpos newspeed
+  where accel = acceleration (Body m pos speed) neighbours
+        newspeed = speed + dt *^ accel
+        newpos = pos + dt *^ P newspeed
+
+
+--------------------------------------------------------------------------------
+-- EXAMPLES
+--------------------------------------------------------------------------------
+
+b1 = Body 42 (P $ V3 0 0 0) (V3 0 0 0)
+b2 = Body 11 (P $ V3 1 2 3) (V3 0 0 0)
+b3 = Body 5 (P $ V3 5 2 1) (V3 0 0 0)
+

stack.yaml

@@ -0,0 +1,66 @@
+# This file was automatically generated by 'stack init'
+#
+# Some commonly used options have been documented as comments in this file.
+# For advanced use and comprehensive documentation of the format, please see:
+# http://docs.haskellstack.org/en/stable/yaml_configuration/
+
+# Resolver to choose a 'specific' stackage snapshot or a compiler version.
+# A snapshot resolver dictates the compiler version and the set of packages
+# to be used for project dependencies. For example:
+#
+# resolver: lts-3.5
+# resolver: nightly-2015-09-21
+# resolver: ghc-7.10.2
+# resolver: ghcjs-0.1.0_ghc-7.10.2
+# resolver:
+#  name: custom-snapshot
+#  location: "./custom-snapshot.yaml"
+resolver: lts-8.23
+
+# User packages to be built.
+# Various formats can be used as shown in the example below.
+#
+# packages:
+# - some-directory
+# - https://example.com/foo/bar/baz-0.0.2.tar.gz
+# - location:
+#    git: https://github.com/commercialhaskell/stack.git
+#    commit: e7b331f14bcffb8367cd58fbfc8b40ec7642100a
+# - location: https://github.com/commercialhaskell/stack/commit/e7b331f14bcffb8367cd58fbfc8b40ec7642100a
+#   extra-dep: true
+#  subdirs:
+#  - auto-update
+#  - wai
+#
+# A package marked 'extra-dep: true' will only be built if demanded by a
+# non-dependency (i.e. a user package), and its test suites and benchmarks
+# will not be run. This is useful for tweaking upstream packages.
+packages:
+- .
+# Dependency packages to be pulled from upstream that are not in the resolver
+# (e.g., acme-missiles-0.3)
+extra-deps: []
+
+# Override default flag values for local packages and extra-deps
+flags: {}
+
+# Extra package databases containing global packages
+extra-package-dbs: []
+
+# Control whether we use the GHC we find on the path
+# system-ghc: true
+#
+# Require a specific version of stack, using version ranges
+# require-stack-version: -any # Default
+# require-stack-version: ">=1.4"
+#
+# Override the architecture used by stack, especially useful on Windows
+# arch: i386
+# arch: x86_64
+#
+# Extra directories used by stack for building
+# extra-include-dirs: [/path/to/dir]
+# extra-lib-dirs: [/path/to/dir]
+#
+# Allow a newer minor version of GHC than the snapshot specifies
+# compiler-check: newer-minor

test/Spec.hs

@@ -0,0 +1,2 @@
+main :: IO ()
+main = putStrLn "Test suite not yet implemented"