gistfile1.txt

// Heron's method
function sqrt(n){
	var close_enuf = 0.001
	function iterate(guess){
		console.log(guess);
		var next = (guess + n/guess)/2;
		return (Math.abs(guess-next) < close_enuf) ? next : iterate(next); 
	}
	iterate(Math.random()*n); 
}

// My variation
function sqrt(n){
	let close_enuf = 0.001
	function iterate(guess){
		console.log(guess);
		let factor = n/guess;
		let diff = Math.abs(guess - factor);
		let min = (factor > guess) ? guess : factor;
		let next = min + diff*Math.random();
		return (Math.abs(guess-next) < close_enuf) ? next : iterate(next); 
	}
	iterate(Math.random()*n); 
}

//Fixed_point translated from SICP
function fixed_point(f, first_guess){
	let tolerance = 0.001
	function is_close_enuf(a, b){
		return (tolerance > Math.abs(a-b));
	}
	function try_the(guess){
		let next = f(guess);
		if(is_close_enuf(guess,next))
			return next;
		else
			return try_the(next);
	}
	return try_the(first_guess);
}

// Could use fixed_point by calling fixed_point(Math.cos, Math.random());

// Can also use it for Heron's method with the appropriate argument
// This function does that:

function generate(n){
	function heron(x){
		return (x+n/x)/2;
	}
	return heron; 
}

// Find the square root of 4 by calling fixed_point(generate(4), Math.random())