The Bailey-Borwein-Plouffe formula for determining the digits of pi was discovered in 1995. This formula has been utilized to find the exact digits of pi to many decimal places.
I recently re-implemented my legacy C and FreeLIP program that utilized the BBP formula. The new C# application uses a homegrown big unsigned decimal number package that includes methods for +, -, *, / operators and an exponentiation (power) function. I used short integers (16-bit signed integers) to represent the individual digits of the number in any base whose square can be expressed as a positive short integer. That includes the decimal base 10 and hexadecimal base 16. For this application the base was chosen to be 10. Also, included was a n-digits of pi function that used the C# language’s built-in BigInteger data type. Below are some screen shots of the program in action.
As you can easily see the BigInteger implementation is an order of magnitude faster that the BigDecimal version (actually around 27+ times faster).
Last, we include a link to a PDF containing data comparing calculations performed on a Intel based desktop versus an AMD based laptop.
Benchmark Calculations Using the Application BigIntegerPi
Author: jamespatewilliamsjr
My whole legal name is James Pate Williams, Jr. I was born in LaGrange, Georgia approximately 70 years ago. I barely graduated from LaGrange High School with low marks in June 1971. Later in June 1979, I graduated from LaGrange College with a Bachelor of Arts in Chemistry with a little over a 3 out 4 Grade Point Average (GPA). In the Spring Quarter of 1978, I taught myself how to program a Texas Instruments desktop programmable calculator and in the Summer Quarter of 1978 I taught myself Dayton BASIC (Beginner's All-purpose Symbolic Instruction Code) on LaGrange College's Data General Eclipse minicomputer. I took courses in BASIC in the Fall Quarter of 1978 and FORTRAN IV (Formula Translator IV) in the Winter Quarter of 1979. Professor Kenneth Cooper, a genius poly-scientist taught me a course in the Intel 8085 microprocessor architecture and assembly and machine language. We would hand assemble our programs and insert the resulting machine code into our crude wooden box computer which was designed and built by Professor Cooper. From 1990 to 1994 I earned a Bachelor of Science in Computer Science from LaGrange College. I had a 4 out of 4 GPA in the period 1990 to 1994. I took courses in C, COBOL, and Pascal during my BS work. After graduating from LaGrange College a second time in May 1994, I taught myself C++. In December 1995, I started using the Internet and taught myself client-server programming. I created a website in 1997 which had C and C# implementations of algorithms from the "Handbook of Applied Cryptography" by Alfred J. Menezes, et. al., and some other cryptography and number theory textbooks and treatises.
View all posts by jamespatewilliamsjr
Numerical Explorations 
One thought on “The Bailey-Borwein-Plouffe Formula for Calculating the First n Digits of Pi”