(42S) Iterative refinement

[Werner]

See the article with the same subject. I never know where to post these, so I put them in both :-). And comments are disabled for articles, for some reason.
Quick usage instructions:
Put A and b on the stack, just as you would for a normal solve, so b ENTER A
Then XEQ "/IR" will solve the system and perform a corrective refinement step, leaving the result in X. If you are careful to leave the stack undisturbed (as browsing the result with EDIT, arrows, EXITALL will do), you may execute further refinement steps with R/S.

Code:

                L       X       Y       Z       T
00 { 58-Byte Prgm }
01>LBL "/IR"            A       b
02 X<>Y
03 ENTER
04 TRANS                bt      b       A
05 RCL ST Z             A       bt      b       A
06 STO/ ST Z            A       bt      x       A
07 TRANS
08 EDIT
09 INSR                 0       bt      x       A
10 Rv                   bt      x       A
11 PUTM
12 CLX
13 RCLEL
14 EXITALL
15 TRANS                bA      x       A
16 X<>Y
17>LBL 02               x       bA      A
18 STO ST L     x       x       bA      A
19 EDIT
20 INSR
21 -1
22 EXITALL      x       -1x     bA      A
23 X<> ST L     -1x     x       bA      A
24 RCL ST Y     -1x     bA      x       bA      A
25 RCLx ST L            Ax-b    x       bA      A
26 RCL/ ST T            -dx     x       bA      A
27 -                    x       bA      A
28 RTN
29 GTO 02
30 END

Werner