Skip to content

Latest commit

 

History

History
63 lines (51 loc) · 2.72 KB

READMEOLD.md

File metadata and controls

63 lines (51 loc) · 2.72 KB

Comparison with Fortran

The original purpose of the package was to simplify translation of Fortran codes, say

  • the codes accompanying the book Numerical Solution of Hyperbolic Partial Differential Equations by prof. John A. Trangenstein Please refer here and here

  • Clawpack (stands for Conservation Laws Package) by prof. Randall J. LeVeque

see also translation to Julia of Fortran codes from ClawPack

The directory examples of hyperbolic_PDE contains at the moment a translation of explicit upwind finite difference scheme for scalar law advection equation from the book Numerical Solution of Hyperbolic Partial Differential Equations by prof. John A. Trangenstein.

  • examples/scalar_law/PROGRAM0/main.jl The original Fortran arrays u(-2:ncells+1), x(0:ncells), flux(0:ncells) transformed to 1-based Julia arrays by shifting index expressions
    u    = Array{Float64}(undef, ncells+4)
    x    = Array{Float64}(undef, ncells+1)
    flux = Array{Float64}(undef, ncells+1)
```{+ examp}(undef,es/scalar_law/PROGRAM0/main_offset_array.jl
    Exemplary _use case_ of this package
```julia
    u    = OffsetArray{Float64}(undef, -2:ncells+1)
    x    = OffsetArray{Float64}(undef,  0:ncells)
    flux = OffsetArray{Float64}(undef,  0:ncells)
  • Timings for baseline with @inbounds annotation:
  0.103402 seconds (21 allocations: 235.531 KB)
  • Timing for OffsetArray version with @inbounds annotation:
  0.103987 seconds (16 allocations: 235.094 KB)
  • UPDATE: Added
    • examples/scalar_law/PROGRAM1/...
[~/w/m/O/e/s/PROGRAM1] $ julia linaddmain.jl --cells=10000 --runs=3                                                                           ms  master|✚ 1…
  0.672295 seconds (42.90 k allocations: 1.990 MB)
  0.509693 seconds (18 allocations: 313.281 KB)
  0.512243 seconds (18 allocations: 313.281 KB)
[~/w/m/O/e/s/PROGRAM1] $ julia linaddmain.jl --cells=100000 --runs=3                                                                      6134ms  master|✚ 1…
  7.270463 seconds (42.90 k allocations: 4.736 MB)
  7.177485 seconds (18 allocations: 3.053 MB)
  7.248687 seconds (18 allocations: 3.053 MB)
Fortran timing for `100000` number of cells

real    0m4.781s
user    0m4.760s
sys     0m0.000s

That is 7.2s for Julia script vs. 4.8s for Fortran.