haampie

using BenchmarkTools

import Base.BLAS: BlasInt, @blasfunc, liblapack

# subroutine dhseqr 	( 	
#       character  	JOB,
# 		character  	COMPZ,
# 		integer  	N,
# 		integer  	ILO,
# 		integer  	IHI,

haampie

import Base: start, next, done

using BenchmarkTools

mutable struct RowJacobi{matT,vecT}
    A::matT
    x::vecT
    next::vecT
    b::vecT
    maxiter::Int

haampie

struct UnsafeView{T, N} <: DenseArray{T, N}
    dim::NTuple{N, Int}
    ptr::Ptr{T}
end

const UnsafeVectorView{T} = UnsafeView{T,1}
const UnsafeMatrixView{T} = UnsafeView{T,2}

@inline Base.size(v::UnsafeView) = v.dim
@inline Base.size(v::UnsafeVectorView, idx::Int) = idx == 1 ? v.dim[idx] : 1

haampie

function literature_example()
    # Problem: Δu + 1000uₓ = f
    # u = 0 on the boundaries
    # f(x, y, z) = exp(xyz) sin(πx) sin(πy) sin(πz)
    # 2nd order central differences (shows serious wiggles)

    # Unknowns per dimension
    N = 50

    # Total number of unknowns

haampie

import Base.LinAlg.BlasFloat
import Base.LinAlg.BLAS: gemv!, gemv, axpy!

using BenchmarkTools

function classical_gram_schmidt!{T<:BlasFloat}(V::StridedMatrix{T}, w::StridedVector{T})
    
    # orthogonalize
    h = gemv('T', one(T), V, w)
    gemv!('N', -one(T), V, h, one(T), w)

haampie

using BenchmarkTools
using IterativeSolvers

module GMRES

using Base.LinAlg.axpy!

function gmres(A, b; outer::Int = 5, restart::Int = 20, tol = sqrt(eps(real(eltype(b)))))
  T = eltype(b)

haampie

<?php

function take(Iterator $it, int $n) {
    for ($i = 0; $i < $n && $it->valid(); $i++, $it->next()) {
        yield $it->current();
    }
}

function filter(Iterator $it, callable $f) {
    foreach ($it as $item) {

haampie

<?php

final class User
{
    private $name;

    public function __construct(string $name)
    {
        $this->name = $name;
    }

haampie

#include <iostream>
#include <tuple>

using pell = std::pair<size_t, size_t>;

inline pell next(pell const &solution)
{
  return {
    2 * solution.first + 3 * solution.second, 
    2 * solution.second + solution.first

haampie

                                                                                                                                                                                                                   3^2 -   2 * 2^2                                                                                                                                                                                                                   = 1
                                                                                                                                                                                                                   9^2 -   5 * 4^2                                                                                                                                                                                                                   = 1