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(15C) Accurate TVM for HP-15C - Jeff_Kearns - 01-10-2014 03:36 AM
Note: See post #6 for the latest version (now 40 lines in length). I have left previous posts unedited to avoid causing confusion. This is an adaptation of the Pioneer's (42S/35S/33S/32Sii/32S) Accurate TVM routine for the HP-15C using Karl Schneider's technique for invoking SOLVE with the routine written as a MISO (multiple-input, single-output) function, using indirect addressing. 001 f LBL E 002 STO(i) 003 RCL 2 004 EEX 005 2 006 ÷ 007 ENTER 008 ENTER 009 1 010 + 011 LN 012 X<>Y 013 LSTx 014 1 015 X≠Y 016 - 017 ÷ 018 * 019 RCL * 1 020 e^x 021 ENTER 022 RCL * 3 023 X<>Y 024 1 025 - 026 RCL * 4 027 EEX 028 2 029 RCL ÷ 2 030 RCL + 6 031 * 032 + 033 RCL + 5 034 RTN Usage instructions: 1. Store 4 of the following 5 variables, using appropriate cash flow conventions as follows: - N STO 1 --- Number of compounding periods
- I STO 2 --- Interest rate (periodic) expressed as a %
- B STO 3 --- Initial Balance or Present Value
- P STO 4 --- Periodic Payment
- F STO 5 --- Future Value
- B/E STO 6 --- Begin/End Mode. The default is 0 for regular annuity or End Mode.
2. Store the register number containing the floating variable to the indirect storage register. 3. f SOLVE E Example from the HP-15C Advanced Functions Handbook- "Many Pennies (alternatively known as A Penny for Your Thoughts): A corporation retains Susan as a scientific and engineering consultant at a fee of one penny per second for her thoughts, paid every second of every day for a year. Rather than distract her with the sounds of pennies dropping, the corporation proposes to deposit them for her into a bank account in which interest accrues at the rate of 11.25 percent per annum compounded every second. At year's end these pennies will accumulate to a sum total = (payment) X ((1+i/n)^n-1)/(i/n) where payment = $0.01 = one penny per second, i = 0.1125 = 11.25 percent per annum interest rate, n = 60 X 60 X 24 X 365 = number of seconds in a year. Using her HP-15C, Susan reckons that the total will be $376,877.67. But at year's end the bank account is found to hold $333,783.35 . Is Susan entitled to the $43,094.32 difference?" - 31,536,000 STO 1
- (11.25/31,536,000) STO 2
- 0 STO 3
- -0.01 STO 4
- 5 STO I
- f SOLVE E
The HP-15C now gives the correct result: $333,783.35. Thanks to Thomas Klemm for debugging the above routine. Edit: The code has been edited to reflect Thomas' suggested changes below. Jeff Kearns RE: Accurate TVM for HP-15C - Thomas Klemm - 01-10-2014 05:31 AM
(01-10-2014 03:36 AM)Jeff_Kearns Wrote: 027 RCL 2Any reason for not using: 027 EEX 028 2 029 RCL ÷ 2 Just curios. RE: Accurate TVM for HP-15C - Jeff_Kearns - 01-10-2014 05:38 AM
(01-10-2014 05:31 AM)Thomas Klemm Wrote: Any reason for not using: Oversight! I note that you 'did' suggest this change in the other thread. I will test it tomorrow and edit the post accordingly (or would that cause an issue with the follow-on posts?). Jeff RE: Accurate TVM for HP-15C - Dieter - 01-16-2014 09:32 PM
(01-10-2014 03:36 AM)Jeff_Kearns Wrote: Edit: The code has been edited to reflect Thomas' suggested changes below. There's a 1/x too much now. ;-) Obviously a leftover from the original code. Take a look at line 30. Dieter RE: Accurate TVM for HP-15C - Jeff_Kearns - 01-16-2014 09:38 PM
Dieter wrote: "There's a 1/x too much now. ;-) Obviously a leftover from the original code. Take a look at line 30." Fixed! Thanks Dieter. RE: Accurate TVM for HP-15C - Jeff_Kearns - 05-25-2014 03:03 PM
Most accurate version is now 40 lines: 001 - LBL E 002 - STO (i) 003 - RCL 2 004 - EEX 005 - 2 006 - / 007 - ENTER 008 - ENTER 009 - 1 010 - + 011 - LN 012 - x<>y 013 - LSTx 014 - 1 015 - TEST 6 016 - - 017 - / 018 - x 019 - RCLx 1 020 - ENTER 021 - e^x 022 - RCLx 3 023 - x<>y 024 - 2 025 - / 026 - SINH 027 - LSTx 028 - e^x 029 - x 030 - 2 031 - x 032 - RCLx 4 033 - EEX 034 - 2 035 - RCL/ 2 036 - RCL+ 6 037 - x 038 - + 039 - RCL+ 5 040 - RTN RE: (15C) Accurate TVM for HP-15C - Nick - 08-27-2016 10:07 PM
UI Mod: 40 step version w/ 12C Layout Layout (12C): [A: N], [B: I], [C: PV], [D: PMT], [E: FV] Clear: GSB 2 - Mnemonic: 12C - Note: You must run Clear to initialize the program before use. Store: STO {A..E} Solve: [f] {A..E} or for User Mode simply {A..E} - (Option) Set X & Y to a range of values to search (slightly faster to run and much slower to key) - (Option) Don't bother entering anything as most of the time it will work as-is. Use 1 ENTER or -1 ENTER and re-run if SOLVE fails. (faster to key) Recall: RCL {A..E} Set End (default): 0 STO 2 Set Begin: 1 STO 2 - Mnemonic: 12C Code: `01 LBL A` Comments: - Uses 1x1 Matricies to treat A..E as direct access registers. This requires R0=1 and R1=1 for A..E to function. This is set via MATRIX 1 in the Initialize/Clear routine. The contents of A..E will not be lost if R0 or R1 are changed, but they must be reset with MATRIX 1 (or manually) to restore direct access. - The 12C style version in the 15C Advanced Functions Handbook p24-30 [2012] by contrast is 108 steps long. RE: (15C) Accurate TVM for HP-15C - Nick - 08-27-2016 10:34 PM
Issue: The 40 step version fails when I = 0 (either by setting it as a value or when searching for I). Workaround: Set X & Y = 1 when solving for I (or a similar known range to search) Set I = (a very small interest rate) to approximate 0% interest problems or solve manually. |