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# Thread: Surrender Question

1. Did you find this post helpful? Yes | No
Originally Posted by Cacarulo
After reviewing my code I realized that the method I was using was a Gaussian approximation. Back in the days when computers weren't that fast, doing it under strict combinatorial analysis took a lot of processing time, especially in shoes. In fact, to obtain the probability of a certain RC with N cards remaining, it was much faster to use a Normal approximation (there is an explanation of how to do it in TOB). My idea is to try to improve the results using the Gaussian approach.
Anyway, I can also do it using combinatorial analysis. Here are my numbers to 12 digits of precision so we can see if our programs match:

Code:
```1) RC =  +1 | CR = 38 | A removed (1D)

|   0.118480844761 |   0.062504209740   0.073908841110   0.073908841110   0.073908841110   0.073908841110   0.073908841110   0.078198599809   0.078198599809   0.078198599809    0.333355785282 |
|   0.118480844761 |   2.375159970136   2.808535962172   2.808535962172   2.808535962172   2.808535962172   2.808535962172   2.971546792759   2.971546792759   2.971546792759  12.667519840725 |

2) RC = -13 | CR = 52 | No cards removed (2D)

|   0.001319524919 |   0.051923076923   0.101923076923   0.101923076923   0.101923076923   0.101923076923   0.101923076923   0.076923076923   0.076923076923   0.076923076923    0.207692307692 |
|   0.001319524919 |   2.700000000000   5.300000000000   5.300000000000   5.300000000000   5.300000000000   5.300000000000   4.000000000000   4.000000000000   4.000000000000  10.800000000000 |

3) RC = -13 | CR = 52 | A removed (2D)

|   0.001748370518 |   0.046449210406   0.101757691595   0.101757691595   0.101757691595   0.101757691595   0.101757691595   0.077474361349   0.077474361349   0.077474361349    0.212339247570 |
|   0.001748370518 |   2.415358941111   5.291399962953   5.291399962953   5.291399962953   5.291399962953   5.291399962953   4.028666790158   4.028666790158   4.028666790158  11.041640873651 |

4) RC = -13 | CR = 52 | A,T,7 removed (2D)

|   0.002324475807 |   0.048194174755   0.102325104020   0.102325104020   0.102325104020   0.102325104020   0.102325104020   0.069010552983   0.078869203409   0.078869203409    0.213431345344 |
|   0.002324475807 |   2.506097087263   5.320905409029   5.320905409029   5.320905409029   5.320905409029   5.320905409029   3.588548755129   4.101198577291   4.101198577291  11.098429957881 |

5) RC = -13 | CR = 52 | T,7 removed (2D)

|   0.001752858519 |   0.053838176772   0.102492222353   0.102492222353   0.102492222353   0.102492222353   0.102492222353   0.068501931969   0.078287922250   0.078287922250    0.208622934993 |
|   0.001752858519 |   2.799585192160   5.329595562356   5.329595562356   5.329595562356   5.329595562356   5.329595562356   3.562100462394   4.070971957022   4.070971957022  10.848392619621 |
```
Sincerely,
Cac

PS: These days I am going to publish the exact insurance indices for Hi-Lo taking into account different penetrations.
It appears we are in complete agreement.

This is how I output insurance indexes:
Code:
```Count tags {1,-1,-1,-1,-1,-1,0,0,0,1}
Decks: 8
Insurance Data (without regard to hand comp)
No subgroup (removals) are defined

**** Player hand: x-x ****
Cards   RC      TC ref

384     29      3.93
383     28      3.80
382     27      3.68
379     26      3.57
376     25      3.46
370     24      3.37
362     23      3.30
352     22      3.25
341     21      3.20
327     20      3.18
313     19      3.16
298     18      3.14
283     17      3.12
267     16      3.12
251     15      3.11
234     14      3.11
218     13      3.10
201     12      3.10
185     11      3.09
168     10      3.10
151     9       3.10
134     8       3.10
117     7       3.11
100     6       3.12
83      5       3.13
66      4       3.15
49      3       3.18
32      2       3.25
15      1       3.47
2       0       0.00
1       1       52.00

Press any key to continue```

Above outputs in about a second or so. I can generate indexes for HiLo fairly efficiently. It takes about 3 minutes to generate HiLo RC indexes for a hand of 2-2 for 208 cards remaining from 8 decks for all up cards. T-6 for 8 decks takes only a second or so.

It's a different story for Wong Halves. For 8 decks with 208 cards remaining HiLo has 49 count subsets whereas Wong Halves has 582905. Insurance indexes are somewhat attainable but others are more of a problem.

8 decks is about the worst case to worry about. I wonder if efficiency can be further improved.

k_c

2. Did you find this post helpful? Yes | No
Originally Posted by k_c
It appears we are in complete agreement.

This is how I output insurance indexes:
Code:
```Count tags {1,-1,-1,-1,-1,-1,0,0,0,1}
Decks: 8
Insurance Data (without regard to hand comp)
No subgroup (removals) are defined

**** Player hand: x-x ****
Cards   RC      TC ref

384     29      3.93
383     28      3.80
382     27      3.68
379     26      3.57
376     25      3.46
370     24      3.37
362     23      3.30
352     22      3.25
341     21      3.20
327     20      3.18
313     19      3.16
298     18      3.14
283     17      3.12
267     16      3.12
251     15      3.11
234     14      3.11
218     13      3.10
201     12      3.10
185     11      3.09
168     10      3.10
151     9       3.10
134     8       3.10
117     7       3.11
100     6       3.12
83      5       3.13
66      4       3.15
49      3       3.18
32      2       3.25
15      1       3.47
2       0       0.00
1       1       52.00

Press any key to continue```

Above outputs in about a second or so. I can generate indexes for HiLo fairly efficiently. It takes about 3 minutes to generate HiLo RC indexes for a hand of 2-2 for 208 cards remaining from 8 decks for all up cards. T-6 for 8 decks takes only a second or so.

It's a different story for Wong Halves. For 8 decks with 208 cards remaining HiLo has 49 count subsets whereas Wong Halves has 582905. Insurance indexes are somewhat attainable but others are more of a problem.

8 decks is about the worst case to worry about. I wonder if efficiency can be further improved.

k_c
Excellent!

Here is my approach for SD:

Code:
```+----------+----------------------------+-----+-----+---------------------+
|   Play   |              TC            |  RC | IRC |          EV         |
+----------+--------------+-------------+-----+-----+---------------------+
|    Ins   |   1.368421   |     1/ 38   |   1 |   0 | 0.00673558467365609 |
+----------+--------------+-------------+-----+-----+---------------------+```
This is the precise index for SD. The first TC where a positive advantage exists occurs exactly when the RC equals +1 and there are 38 cards left in the deck. Index = 1/38*52 = 1.368421
Notice that the EV at this point is equal to 0.00673558467365609%
In the same way, and for a penetration of 32/52 cards or 20 cards remaining, the average RC index between 51 and 20 cards turns out to be equal to +1.

For 2D and 26 cards left:

Code:
```+----------+----------------------------+-----+-----+---------------------+
|   Play   |              TC            |  RC | IRC |          EV         |
+----------+--------------+-------------+-----+-----+---------------------+
|    Ins   |   2.400000   |     3/ 65   |   3 |   0 | 0.07726304005333251 |
+----------+--------------+-------------+-----+-----+---------------------+```

For 3D and 39 cards left:

Code:
```+----------+----------------------------+-----+-----+---------------------+
|   Play   |              TC            |  RC | IRC |          EV         |
+----------+--------------+-------------+-----+-----+---------------------+
|    Ins   |   2.701299   |     4/ 77   |   5 |   0 | 0.01586588260364952 |
+----------+--------------+-------------+-----+-----+---------------------+```

For 4D and 52 cards left:

Code:
```+----------+----------------------------+-----+-----+---------------------+
|   Play   |              TC            |  RC | IRC |          EV         |
+----------+--------------+-------------+-----+-----+---------------------+
|    Ins   |   2.857143   |     5/ 91   |   6 |   0 | 0.00225658769383852 |
+----------+--------------+-------------+-----+-----+---------------------+```
For 5D and 65 cards left:

Code:
```+----------+----------------------------+-----+-----+---------------------+
|   Play   |              TC            |  RC | IRC |          EV         |
+----------+--------------+-------------+-----+-----+---------------------+
|    Ins   |   2.959350   |     7/123   |   8 |   0 | 0.02248153833293021 |
+----------+--------------+-------------+-----+-----+---------------------+```
For 6D and 78 cards left:

Code:
```+----------+----------------------------+-----+-----+---------------------+
|   Play   |              TC            |  RC | IRC |          EV         |
+----------+--------------+-------------+-----+-----+---------------------+
|    Ins   |   3.014493   |     8/138   |   9 |   0 | 0.00370493169572494 |
+----------+--------------+-------------+-----+-----+---------------------+```
Sincerely,
Cac

3. Did you find this post helpful? Yes | No
Wonderful! However, there is not very much meat in 6 or 8 deck games, and also there are no available single deck games. I greatly hope to see these numbers on 2-deck games.

4. Did you find this post helpful? Yes | No
Originally Posted by aceside
Wonderful! However, there is not very much meat in 6 or 8 deck games, and also there are no available single deck games. I greatly hope to see these numbers on 2-deck games.
I've posted a 2D index.

Sincerely,
Cac

5. Did you find this post helpful? Yes | No
For 7D and 52 cards remaining:

Code:
```+----------+----------------------------+-----+-----+---------------------+
|   Play   |              TC            |  RC | IRC |          EV         |
+----------+--------------+-------------+-----+-----+---------------------+
|    Ins   |   3.058824   |     8/136   |   9 |   0 | 0.00005756832546222 |
+----------+--------------+-------------+-----+-----+---------------------+
```

For 8D and 52 cards remaining:

Code:

Code:
```+----------+----------------------------+-----+-----+---------------------+
|   Play   |              TC            |  RC | IRC |          EV         |
+----------+--------------+-------------+-----+-----+---------------------+
|    Ins   |   3.091892   |    11/185   |  10 |   0 | 0.00105372979730678 |
+----------+--------------+-------------+-----+-----+---------------------+
```

Sincerely,
Cac

6. Did you find this post helpful? Yes | No
Originally Posted by Cacarulo
I've posted a 2D index.

Sincerely,
Cac
Nice, I just saw it, but can you dig a little more into this? Post the 2-deck results like what K_C just did for 8-decks, like this:
100 6 3.12
83 5 3.13
66 4 3.15
49 3 3.18
32 2 3.25
15 1 3.47

7. Did you find this post helpful? Yes | No
Originally Posted by aceside
Nice, I just saw it, but can you dig a little more into this? Post the 2-deck results like what K_C just did for 8-decks, like this:
100 6 3.12
83 5 3.13
66 4 3.15
49 3 3.18
32 2 3.25
15 1 3.47
Sorry, that wouldn't be an index. The index should be the minimum TC at which one should buy insurance. That would include any TC greater or equal than the index.

Sincerely,
Cac

8. Did you find this post helpful? Yes | No
Originally Posted by Cacarulo
Sorry, that wouldn't be an index. The index should be the minimum TC at which one should buy insurance. That would include any TC greater or equal than the index.

Sincerely,
Cac
One main point here is to find out how the index varies with the dealing depth. Some indices increase while others decrease. K_C has showed that the insurance index mostly decreases with the dealing depth. It does not strictly decrease all the way though. I guess this is true for both 8-decks and 2-decks.

9. Did you find this post helpful? Yes | No
Originally Posted by aceside
One main point here is to find out how the index varies with the dealing depth. Some indices increase while others decrease. K_C has showed that the insurance index mostly decreases with the dealing depth. It does not strictly decrease all the way though. I guess this is true for both 8-decks and 2-decks.
It is one thing to see how an index varies according to penetration and another thing is the index itself.
K_C showed in his data that the lowest TC at which there is an advantage is found when there are 185 cards remaining and the RC is equal to +11. That corresponds to the index we need to find and the value is 3.091892. Any TC above or equal to that index will have a positive advantage and therefore we must buy insurance.
Suppose we know in advance that the index is 3.09 but we have to play with horrible penetration. When the TC is greater than or equal to 3.09 we will buy insurance. If you look at the data, that will always happen.

Sincerely,
Cac

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