*********************************************** eCalc - A program to find e - about 2.718281828 *********************************************** Requirements to using eCalc V2.5: - Amiga with 68020 or better CPU (a FPU is not needed and not used anyway) - Workbench/Kickstart 2.04 or better (I haven't tested it with less than 3.0) - About twice as much bytes memory as the accuracy you want e - Time (and patience!) It uses no external libraries. This program is Freeware: It may be distributed freely for non-commercial purposes. It should be free and a copying fee must not exceed £2. This program may not be distributed with any magazine-coverdisk without written permission. It may be included in any PD-library or on CDs including PD software, such as the Fish, Aminet and other series including similar free software. The program and this docfile may not be changed or modified! YOU USE THIS PROGRAM ON YOUR OWN RISK. THE AUTHOR CAN NOT AND WILL NOT GUARANTEE ITS ACCURACY, NOR ANY OTHER DAMAGES ARISING FROM ANY USE OR MISUSE OF THIS PROGRAM AND DOCUMENTATION. If publishing a result produced by eCalc, please give credit to the author and state which version of the program you used (V2.5). History ------- This program was originally made in only 20 minutes modifying the sourcecode of my piCalc program (calculates pi). It is many times faster than piCalc though and should be able to calculate How to use it ------------- eCalc is Shell/CLI-only utility. To use it you have to open a shell-window. In its simplest form you write (from Shell) You can always stop the program with Ctrl-C. "eCalc XXXXX" where XXXXX is the number of decimals eCalc should calculate. The higher number of decimals the more time the calculation will take. If you think of calculating many decimals (more than 20000) you should run eCalc with the "ESTIMATE" option: "eCalc estimate 100000" will estimate how much time a calculation of 100000 decimals will take, so that you won't be surprised by how slow things are going. If you want to save the result to a file, use "SAVEFILE=filename", the result will be written to this file when it has finished. Those options in full --------------------- Type "eCalc ?" for the eCalc Template: DECIMALS/N,EVERY/N,SAVEFILE,SAVEEVERY/N,NOTIFY/S,NOOUTPUT/S,ESTIMATE/S DECIMALS is the number of decimal places you want eCalc to calculate, this must be between 1 and 2,147,483,647. Except when "ESTIMATE" is selected, you will need just below twice as much memory free as the number of decimals you want to calculate e to. (e.g. 1,000,000 decimals requires almost 2 MB memory.) (If not specified, the program uses 45 decimals) EVERY is how often you want eCalc to output its current calculation of e. If you use "EVERY 10000" eCalc will output to screen (StdOut) when it has 10000, 20000, 30000 and so on of decimals. This option is probably most useful when used with the "NOTIFY" option. SAVEFILE when specified eCalc will save its calculation to the specified file, this it a much nicer method than running eCalc with a ">" redirection file. Beware: If eCalc can't create this file it would not give any error messages, just continue on! SAVEEVERY specifies how often eCalc should save its current calculation to SAVEFILE. NOTIFY is a very useful option in conjunction with the EVERY and SAVEFILE options. It notifies you how far it has come, writing "Dec: XXXX" to the Shell-window, where XXXX is how many decimals it has calculated so far, so you have some kind of control of the process. Write NOTIFY EVERY 1000 to have eCalc notify you every time it has calculated 1000 new decimals. NOOUTPUT is useful when you use the SAVEFILE option and don't want e to be echoed to screen as this can take quite a while with many decimals. ESTIMATE will estimate the TIME needed to calculate e. The estimating may take a number of seconds (2-6) but will display a rough indication on how long the calculation will take: You should not touch the mouse or keyboard during this test, as this will cause eCalc to over-estimate the time needed. Is eCalc calculating the right value for e? --------------------------------------------- Actually I don't know, it uses the same routines as piCalc and piCalc seems calculate pi correctly. The first decimals of e seems to be correct, as I have made another (extremely much slower) program using the definition and got the same value. You should not depend on eCalc giving you the right value, but it is probably correct (I hope). Please don't have a large number of other programs running when eCalc is busy calculating. A single bug in any of the programs running alongside eCalc could accidentally write to a memory location used by eCalc and giving a wrong result as eCalc does absolutely NONE checking on the result as this would decrease performance considerably. Program technicals (programmers) --------------------------------- This program uses 32/64 bit integer math, using the Mulu.L/Divu.L instructions heavily. The speed of this program therefore is largely dependent on the speed the CPU carries out such multiplications and dividitions. The program stores e in longwords, each containing 9 digits. This limits the program to values multiple by 9. (9,18,27,36...) Why is 68020 required? Just because I was able to make the program 3 times faster when I could 68020 instructions instead of 68000 only. Program technicals (math) ------------------------- Calculation method: e = 1/0! + 1/1! + 1/2! + 1/3! + 1/4! + 1/5! ... where 0! = 1 1! = 1 2! = 1 * 2 = 2 3! = 1 * 2 * 3 = 6 4! = 1 * 2 * 3 * 4 = 24 and so on If you know a better formula/method or know another e-calculation program (that is faster), please write to me! Author ------ Write if you know of any SERIOUS bugs (e is not accurate, fails on 68060, etc.) If you have calculated e with more than 1,000,008 decimals using this program or know a more efficient formula or another Amiga program that is faster, please write! PS: Also try my program piCalc V2.5 that is identical to eCalc V2.5 except that it calculates pi=3.14159265358979323846264338327950... (I only know the number this far by heart!) My address: Steffen Thorsen Fjordgt. 8a N-4300 Sandnes Norway (No EMail yet, but I'll have Internet access from September 1995)