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+--- Thread: (48G 49 50g) INVERT Transform (/thread-12735.html)
(48G 49 50g) INVERT Transform - John Keith - 04-03-2019 05:27 PM
Programs for the INVERT transform and its inverse.
First, the INVERT transform: Explanation of the algorithm here.
Code:
\<< DUP SIZE \-> n
\<< 1 OVER HEAD 2. \->LIST 2. n
FOR k OVER 1. k SUB REVLIST OVER * \GSLIST +
NEXT NIP TAIL
\>>
\>>Next, the INVERTi transform, the inverse of the INVERT transform.
Explained here.Code:
\<< DUP SIZE \-> n
\<< 1 OVER 1. 2. SUB EVAL SWAP - 2. \->LIST 2. n 1. -
FOR k OVER 1. k SUB REVLIST OVER * \GSLIST PICK3 k 1. + GET SWAP - +
NEXT NIP
\>>
\>>For HP-48G compatibility, replace PICK3 with 3 PICK and replace NIP with SWAP DROP.