View source for Turing Exercise

= Class Exercise: Understanding Pseudocode and the Turing Machine =

The Diffusion algorithm

* Inputs:
** Two end temperatures (TL and TR)
** A list of 5 starting temperatures.

* Outputs:
** A list of 5 steady-state temperatures and the heat current.

* Pseudocode:
#	Compute QLA = (TL – TA)/2
#	Compute QAB = (TA – TB)/2
#	Compute QBC = (TB – TC)/2
#	Compute QCD = (TC – TD)/2
#	Compute QDE = (TD – TE)/2
#	Compute QER = (TE – TR)/2
#	Set TA = TA + QLA - QAB
#	Set TB = TB + QAB - QBC
#	Set TC = TC + QBC - QCD
#	Set TD = TD + QCD - QDE
#	Set TE= TE  + QDE - QER
#	If there were changes, go to step 1 


Task: Choose 1 person as the CPU, and 11 others as memory locations (5 temperatures in the first row and 6 Q values in the back row).  The CPU runs through the algorithm one step at a time and issues instructions to the memory locations (who hopefully remember their numbers).

Assume the starting conditions are:

 TL=500	TA=100	TB = 200	TC=300	TD=400	TE=500	TR=100
 QLA	QAB	QBC	QCD	QDE	QER (undefined values at start)

=== Notes ===
Our class was able to achieve all 12 steps in about 5 minutes, giving us a processor speed of 0.04 operations per second (compare to giga-flops…).