[CFD-Lover]

Hi,

I am trying to understand how the design variables work in Dakota through the rosenbrock_grad1 example. It is written in the input file the following lines

variables
  continuous_design = 2
    initial_point          -1.2      1.0
    lower_bounds     -2.0     -2.0
    upper_bounds      2.0      2.0
    descriptors           'x1'     "x2"

The output data is as follows;

%eval_id interface             x1             x2         obj_fn 
1            NO_ID           -1.2              1           24.2 
2            NO_ID   -1.190378659    1.003926888    21.86081004 
3            NO_ID   -1.151893297    1.019634439    14.06928675 
4            NO_ID   -1.027899292    1.070241789    4.131048308 
5            NO_ID   -1.107874463    0.927134653    13.45821149 
6            NO_ID   -1.029995089    1.066491582    4.124017963 
7            NO_ID   -1.030081177    1.066337535    4.124007196 
8            NO_ID  -0.9934415994    0.993092869    3.977612177 
9            NO_ID  -0.8468832877   0.7001142034    3.440208959 
10           NO_ID  -0.6352910806   0.2771289646    4.273536585 
11           NO_ID  -0.8200039089   0.7097994601    3.452238244 
12           NO_ID  -0.8339821922    0.704762764    3.372021914 
13           NO_ID  -0.8340799213     0.70472755    3.372018127 
14           NO_ID  -0.7689485777   0.5950579383    3.130604906 
15           NO_ID  -0.5084232035   0.1563794916    3.318080986 
16           NO_ID   -0.638826993   0.3759563064    2.789075148 
17           NO_ID  -0.5622068585    0.280779996    2.565074954 
18           NO_ID  -0.4086444482   0.0900272163    2.576610576 
19           NO_ID  -0.4835270432   0.1830451829    2.458441409 
20           NO_ID  -0.4663406231    0.196691386    2.193344768 
21           NO_ID  -0.4504720302   0.2092912201    2.107921923 
22           NO_ID  -0.4491701003   0.2103249665    2.107440505 
23           NO_ID  -0.3577662921   0.1221538733    1.846943189 
24           NO_ID 0.007848940813  -0.2305304995    6.301635632 
25           NO_ID  -0.3040330414  0.07032102793    1.749409771 
26           NO_ID   -0.213742729  0.02400761733    1.520166441 
27           NO_ID -0.02497648007 -0.07281792863    1.589945896 
28           NO_ID  -0.1271322754 -0.02041825066    1.404243143 
29           NO_ID  -0.1120762928 0.006353353605    1.240567287 
30           NO_ID  -0.1065156038  0.01624102204    1.226773323 
31           NO_ID  -0.1061827682  0.01683284951     1.22672953 
32           NO_ID -0.01826390544 -0.005478836018    1.040239788 
33           NO_ID   0.3334115455 -0.09472557811    4.683361478 
34           NO_ID  0.02758494418 -0.01711416753   0.9775429489 
35           NO_ID  0.09251943246 -0.003801835611   0.8388020962 
36           NO_ID   0.2617739373   0.0308973236   0.6865663948 
37           NO_ID    0.262489943  0.03104411318   0.6872352464 
38           NO_ID   0.2563788697  0.04737722771   0.5866552687 
39           NO_ID   0.2518705717  0.06114838414   0.5602222351 
40           NO_ID   0.2518177932  0.06130960233   0.5602187066 
41           NO_ID    0.326201532   0.1005458628   0.4574401837 
42           NO_ID   0.6237364868   0.2574909045    1.872280251 
43           NO_ID   0.3753564092   0.1264742928   0.4109678949 
44           NO_ID   0.4084155144   0.1654776743    0.350147914 
45           NO_ID   0.4389218895   0.2014693256   0.3225824196 
46           NO_ID   0.4543467131   0.2196676487   0.3152585667 
47           NO_ID   0.4658080147   0.2109892634   0.2889465038 
48           NO_ID   0.4641815195   0.2122208296   0.2881535728 
49           NO_ID   0.4641433383   0.2122497401   0.2881531557 
50           NO_ID   0.5072743882   0.2518835182     0.24574201 
51           NO_ID   0.6797985878   0.4104186306   0.3698953905 
52           NO_ID   0.5690670593   0.3086657439   0.2087208652 
53           NO_ID   0.5938097678   0.3422459421   0.1757319579 
54           NO_ID   0.6673248931     0.44201887   0.1117641324 
55           NO_ID    0.722867765   0.5174002958  0.07944167647 
56           NO_ID   0.7151680181   0.5258778729   0.1019015005 
57           NO_ID   0.7212726929   0.5191565025  0.07780507594 
58           NO_ID    0.721280345   0.5191480773  0.07780504375 
59           NO_ID   0.7491138608   0.5597946525  0.06313344679 
60           NO_ID   0.8604479237   0.7223809534  0.05183762621 
61           NO_ID   0.8206676337   0.6642879491   0.0406377484 
62           NO_ID   0.8326760661   0.6860949613   0.0332600319 
63           NO_ID   0.8807097954   0.7733230101  0.01477152185 
64           NO_ID   0.9070492301   0.8211547634 0.008890606282 
65           NO_ID   0.9039552932   0.8236502842  0.01346925417 
66           NO_ID   0.9065789303   0.8215340998 0.008739834418 
67           NO_ID   0.9065823909   0.8215313085 0.008739832954 
68           NO_ID   0.9168772563   0.8419195211 0.007067048193 
69           NO_ID   0.9380444518   0.8838395721 0.005369003995 
70           NO_ID   0.9491183736   0.9057706477 0.005034203381 
71           NO_ID   0.9594716956   0.9244138797 0.003107859816 
72           NO_ID    1.000884983   0.9989868078 0.0007758166495 
73           NO_ID   0.9889662676   0.9775247703 0.0001497811442 
74           NO_ID   0.9809287789   0.9819336547   0.0392215249 
75           NO_ID   0.9887705737   0.9776321162 0.000126223435 
76           NO_ID   0.9887766559   0.9776287799 0.0001262184309 
77           NO_ID   0.9810392432    1.018933628   0.3195351433 
78           NO_ID   0.9886992817   0.9780418284 0.0001542863079 
79           NO_ID   0.9887719616   0.9776538396 0.000126094937 
80           NO_ID    0.998581376   0.9983193227 0.0001353129642 
81           NO_ID    0.993418846   0.9874434261 7.494350224e-05 
82           NO_ID   0.9940120895   0.9886932116 7.59464524e-05

According to DAKOTA input file, the initial value has to be -1.2, which is clearly the first value in the third column in the output values. However, the rest of the values aren't as the upper and lower bounds. I am not quite sure how Dakota generates these values in this order for both x1 and x2. I have tried to changes these values but am not getting how it works. Assume that I have only one design variable, and it goes from 4-20, meaning that the lower bound is 4 and the upper is 20 and I want these values to be passed to openFoam in the following order;
4.24, 4.5, ........20. How should the input file look like in order to get this specific range? I tried in the input file but it didn't work, implying that I might have misunderstood some concepts in the Dakota input file. I would appreciate any clarification.

Thanks in advance for your time,