tobin

# Solution to https://twitter.com/iwontoffendyou/status/1704935240907518367
# Tobin Fricke 2023-09-22

import numpy as np
import scipy.optimize

def dist_from_circle_center_to_curve(R):
    # Center of circle of radius R that is tangent to the y axis and the unit circle.
    x0 = R
    

tobin

# Solution to the following puzzle:
# Invert three boolean signals Using only two NOT gates,
# and as many AND or OR gates as needed,
#
# Tobin Fricke 2020-09-03

for x in [True, False]:
    for y in [True, False]:
        for z in [True, False]:
            # If we assume that there is only one solution, then, when searching for the input

tobin

#include <stdio.h>
#include <stdlib.h>

int main(int argc, char **argv) {
  const int baz = rand();       // ok!
  baz = 99;                     // compile-time error.

  static int goo = rand();      // compile-time error.
  goo = 99;                     // ok.

tobin

def exact_sqrt(x):
    """Calculate the square root of an arbitrarily large integer. 

    The result of exact_sqrt(x) is a tuple (a, r) such that a**2 + r = x, where
    a is the largest integer such that a**2 <= x, and r is the "remainder".  If
    x is a perfect square, then r will be zero.

    The algorithm used is the "long-hand square root" algorithm, as described at
    http://mathforum.org/library/drmath/view/52656.html

tobin

% Plot the frequency response  of an ideal active twin-T notch, versus
% bootstrap feedback gain \alpha. 
%
% Tobin Fricke <[email protected]>
% 2013-11-21

% Pick the color map (to make the plot pretty)
cm = jet();

% Choose the frequency axis

tobin

A PDH error signal can be calibrated (into Hz per volt) simply by
observing the peak-to-peak amplitude of the PDH signal as the
cavity is swept through resonance.  Here's the math:

An impedance-matched, lossless cavity has amplitude reflectivity of

    r_c(f) = i f / (i f + pcav)

where pcav is the cavity pole, and f is the detuning frequency (i.e.
the difference between the frequency of the light and the resonant

tobin

tobin

This is valid:

M = [1,2,3]    
for M[0] in range(0,10):
    print M[0]

2013-05-14

The star operator opens tuples and other sequences:

tobin

% Program to solve a sort of magic square, where only the rows and columns
% must sum to the magic constant, and not the diagonals.  Some elements of
% the square are given in advance while others (indicated with 0) are
% unknown.
%
% TF Time-Wasting Project 04-2013

function result = fu_puzzle
puzzle = ...
  [ 1  0  0  0 22

tobin

f_mod = 35.5e6
pcav = 300e3

i = {0, 1}
conj(z) = real(z) - i*imag(z)
r_c(f) = i*f / (i*f + pcav)
pdh(f) = imag(r_c(f)*conj(r_c(f+f_mod))-conj(r_c(f))*r_c(f-f_mod))

set samples 501