Multi-Threading and Parallel Processing in Matlab

Question

I'm coding a project in Matlab, however I want the great efficiency and speed of my execution, for that sake, I want to use parallel processing threads in Matlab as I have multiple objects working or changing their states in a for loop. Is Multi-Threading is appropriate for this purpose? If so, where can I take start or can create a simple thread?

My Code:

% P=501x3 array
for i=1:length(P)
    % I used position for example's sake, meaning object changing its state
    Object1.position=P(i,:);
    Object2.position=P(i,:);
    Object3.position=P(i,:);
    Object4.position=P(i,:);
    % Mulitple objects changing their state on each iteration, after some calculation/formulation.
end

What I need is the basic structure of Multi-Threads according to my scenario if Threading is appropriate in my case. More suggestions for Parallel-Execution or fast processing are welcomed.

Edit1: Parray:

P =

  -21.8318   19.2251  -16.0000
  -21.7386   19.1620  -15.9640
  -21.6455   19.0988  -15.9279
  -21.5527   19.0357  -15.8918
  -21.4600   18.9727  -15.8556
  -21.3675   18.9096  -15.8194
  -21.2752   18.8466  -15.7831
  -21.1831   18.7836  -15.7468
  -21.0911   18.7206  -15.7105
  -20.9993   18.6577  -15.6741
  -20.9078   18.5947  -15.6377
  -20.8163   18.5318  -15.6012
  -20.7251   18.4689  -15.5647
  -20.6340   18.4061  -15.5281
  -20.5432   18.3432  -15.4915
  -20.4524   18.2804  -15.4548
  -20.3619   18.2176  -15.4181
  -20.2715   18.1548  -15.3814
  -20.1813   18.0921  -15.3446
  -20.0913   18.0293  -15.3078
  -20.0015   17.9666  -15.2709
  -19.9118   17.9039  -15.2340
  -19.8223   17.8412  -15.1970
  -19.7329   17.7786  -15.1601
  -19.6438   17.7160  -15.1230
  -19.5547   17.6534  -15.0860
  -19.4659   17.5908  -15.0489
  -19.3772   17.5282  -15.0117
  -19.2887   17.4656  -14.9745
  -19.2004   17.4031  -14.9373
  -19.1122   17.3406  -14.9001
  -19.0241   17.2781  -14.8628
  -18.9363   17.2156  -14.8254
  -18.8486   17.1532  -14.7881
  -18.7610   17.0907  -14.7507
  -18.6736   17.0283  -14.7132
  -18.5864   16.9659  -14.6758
  -18.4994   16.9035  -14.6383
  -18.4124   16.8412  -14.6007
  -18.3257   16.7788  -14.5632
  -18.2391   16.7165  -14.5255
  -18.1526   16.6542  -14.4879
  -18.0663   16.5919  -14.4502
  -17.9802   16.5296  -14.4125
  -17.8942   16.4673  -14.3748
  -17.8084   16.4051  -14.3370
  -17.7227   16.3429  -14.2992
  -17.6372   16.2807  -14.2614
  -17.5518   16.2185  -14.2235
  -17.4665   16.1563  -14.1856
  -17.3815   16.0941  -14.1477
  -17.2965   16.0320  -14.1097
  -17.2117   15.9698  -14.0718
  -17.1271   15.9077  -14.0338
  -17.0426   15.8456  -13.9957
  -16.9582   15.7835  -13.9576
  -16.8740   15.7214  -13.9196
  -16.7899   15.6594  -13.8814
  -16.7060   15.5973  -13.8433
  -16.6222   15.5353  -13.8051
  -16.5385   15.4733  -13.7669
  -16.4550   15.4113  -13.7287
  -16.3716   15.3493  -13.6904
  -16.2884   15.2873  -13.6521
  -16.2053   15.2253  -13.6138
  -16.1223   15.1634  -13.5755
  -16.0395   15.1014  -13.5372
  -15.9568   15.0395  -13.4988
  -15.8742   14.9776  -13.4604
  -15.7918   14.9157  -13.4220
  -15.7095   14.8538  -13.3835
  -15.6273   14.7919  -13.3451
  -15.5453   14.7301  -13.3066
  -15.4634   14.6682  -13.2681
  -15.3816   14.6063  -13.2295
  -15.2999   14.5445  -13.1910
  -15.2184   14.4827  -13.1524
  -15.1370   14.4209  -13.1138
  -15.0557   14.3591  -13.0752
  -14.9746   14.2973  -13.0366
  -14.8936   14.2355  -12.9979
  -14.8127   14.1737  -12.9593
  -14.7319   14.1120  -12.9206
  -14.6513   14.0502  -12.8819
  -14.5707   13.9885  -12.8432
  -14.4903   13.9267  -12.8044
  -14.4100   13.8650  -12.7657
  -14.3299   13.8033  -12.7269
  -14.2498   13.7416  -12.6881
  -14.1699   13.6799  -12.6493
  -14.0901   13.6182  -12.6105
  -14.0104   13.5565  -12.5717
  -13.9308   13.4948  -12.5328
  -13.8513   13.4332  -12.4940
  -13.7720   13.3715  -12.4551
  -13.6927   13.3099  -12.4162
  -13.6136   13.2482  -12.3773
  -13.5346   13.1866  -12.3384
  -13.4556   13.1250  -12.2995
  -13.3768   13.0633  -12.2605
  -13.2982   13.0017  -12.2216
  -13.2196   12.9401  -12.1826
  -13.1411   12.8785  -12.1437
  -13.0627   12.8169  -12.1047
  -12.9845   12.7553  -12.0657
  -12.9063   12.6937  -12.0267
  -12.8283   12.6321  -11.9877
  -12.7503   12.5706  -11.9487
  -12.6725   12.5090  -11.9097
  -12.5947   12.4474  -11.8706
  -12.5171   12.3859  -11.8316
  -12.4395   12.3243  -11.7925
  -12.3621   12.2628  -11.7535
  -12.2848   12.2012  -11.7144
  -12.2075   12.1397  -11.6754
  -12.1304   12.0781  -11.6363
  -12.0533   12.0166  -11.5972
  -11.9764   11.9550  -11.5581
  -11.8995   11.8935  -11.5190
  -11.8228   11.8320  -11.4799
  -11.7461   11.7705  -11.4408
  -11.6695   11.7089  -11.4017
  -11.5930   11.6474  -11.3626
  -11.5166   11.5859  -11.3235
  -11.4403   11.5244  -11.2844
  -11.3641   11.4629  -11.2453
  -11.2880   11.4014  -11.2062
  -11.2120   11.3398  -11.1671
  -11.1360   11.2783  -11.1280
  -11.0602   11.2168  -11.0889
  -10.9844   11.1553  -11.0497
  -10.9087   11.0938  -11.0106
  -10.8331   11.0323  -10.9715
  -10.7576   10.9708  -10.9324
  -10.6821   10.9093  -10.8933
  -10.6068   10.8478  -10.8542
  -10.5315   10.7863  -10.8150
  -10.4563   10.7248  -10.7759
  -10.3812   10.6633  -10.7368
  -10.3062   10.6018  -10.6977
  -10.2312   10.5403  -10.6586
  -10.1564   10.4788  -10.6195
  -10.0816   10.4173  -10.5804
  -10.0068   10.3557  -10.5414
   -9.9322   10.2942  -10.5023
   -9.8576   10.2327  -10.4632
   -9.7831   10.1712  -10.4241
   -9.7087   10.1097  -10.3851
   -9.6343   10.0482  -10.3460
   -9.5600    9.9866  -10.3069
   -9.4858    9.9251  -10.2679
   -9.4117    9.8636  -10.2289
   -9.3376    9.8021  -10.1898
   -9.2636    9.7405  -10.1508
   -9.1897    9.6790  -10.1118
   -9.1158    9.6174  -10.0728
   -9.0420    9.5559  -10.0338
   -8.9683    9.4944   -9.9948
   -8.8946    9.4328   -9.9558
   -8.8210    9.3712   -9.9169
   -8.7474    9.3097   -9.8779
   -8.6739    9.2481   -9.8390
   -8.6005    9.1865   -9.8000
   -8.5272    9.1250   -9.7611
   -8.4539    9.0634   -9.7222
   -8.3806    9.0018   -9.6833
   -8.3074    8.9402   -9.6444
   -8.2343    8.8786   -9.6056
   -8.1612    8.8170   -9.5667
   -8.0882    8.7554   -9.5279
   -8.0152    8.6938   -9.4890
   -7.9423    8.6322   -9.4502
   -7.8695    8.5705   -9.4114
   -7.7967    8.5089   -9.3727
   -7.7239    8.4473   -9.3339
   -7.6513    8.3856   -9.2951
   -7.5786    8.3240   -9.2564
   -7.5060    8.2623   -9.2177
   -7.4335    8.2006   -9.1790
   -7.3610    8.1389   -9.1403
   -7.2885    8.0772   -9.1017
   -7.2161    8.0155   -9.0630
   -7.1438    7.9538   -9.0244
   -7.0715    7.8921   -8.9858
   -6.9992    7.8304   -8.9472
   -6.9270    7.7687   -8.9086
   -6.8548    7.7069   -8.8701
   -6.7827    7.6452   -8.8316
   -6.7106    7.5834   -8.7931
   -6.6385    7.5217   -8.7546
   -6.5665    7.4599   -8.7161
   -6.4945    7.3981   -8.6777
   -6.4226    7.3363   -8.6393
   -6.3507    7.2745   -8.6009
   -6.2788    7.2127   -8.5625
   -6.2070    7.1508   -8.5242
   -6.1352    7.0890   -8.4858
   -6.0635    7.0271   -8.4475
   -5.9917    6.9653   -8.4093
   -5.9200    6.9034   -8.3710
   -5.8484    6.8415   -8.3328
   -5.7768    6.7796   -8.2946
   -5.7052    6.7177   -8.2564
   -5.6336    6.6558   -8.2183
   -5.5621    6.5938   -8.1802
   -5.4906    6.5319   -8.1421
   -5.4191    6.4699   -8.1040
   -5.3476    6.4079   -8.0660
   -5.2762    6.3459   -8.0280
   -5.2048    6.2839   -7.9900
   -5.1334    6.2219   -7.9521
   -5.0621    6.1599   -7.9142
   -4.9908    6.0978   -7.8763
   -4.9194    6.0358   -7.8384
   -4.8482    5.9737   -7.8006
   -4.7769    5.9116   -7.7628
   -4.7057    5.8495   -7.7250
   -4.6344    5.7874   -7.6873
   -4.5632    5.7253   -7.6496
   -4.4920    5.6631   -7.6119
   -4.4209    5.6010   -7.5743
   -4.3497    5.5388   -7.5367
   -4.2786    5.4766   -7.4992
   -4.2074    5.4144   -7.4616
   -4.1363    5.3522   -7.4241
   -4.0652    5.2899   -7.3867
   -3.9941    5.2277   -7.3492
   -3.9231    5.1654   -7.3118
   -3.8520    5.1031   -7.2745
   -3.7809    5.0408   -7.2372
   -3.7099    4.9785   -7.1999
   -3.6389    4.9161   -7.1626
   -3.5678    4.8538   -7.1254
   -3.4968    4.7914   -7.0883
   -3.4258    4.7290   -7.0511
   -3.3548    4.6666   -7.0140
   -3.2838    4.6041   -6.9770
   -3.2128    4.5417   -6.9400
   -3.1418    4.4792   -6.9030
   -3.0708    4.4167   -6.8661
   -2.9998    4.3542   -6.8292
   -2.9288    4.2917   -6.7923
   -2.8578    4.2291   -6.7555
   -2.7868    4.1666   -6.7187
   -2.7158    4.1040   -6.6820
   -2.6448    4.0414   -6.6453
   -2.5738    3.9788   -6.6087
   -2.5028    3.9161   -6.5720
   -2.4318    3.8534   -6.5355
   -2.3608    3.7908   -6.4990
   -2.2897    3.7280   -6.4625
   -2.2187    3.6653   -6.4261
   -2.1477    3.6026   -6.3897
   -2.0766    3.5398   -6.3534
   -2.0056    3.4770   -6.3171
   -1.9345    3.4142   -6.2808
   -1.8634    3.3513   -6.2446
   -1.7924    3.2885   -6.2085
   -1.7213    3.2256   -6.1724
   -1.6501    3.1627   -6.1363
   -1.5790    3.0998   -6.1003
   -1.5079    3.0368   -6.0643
   -1.4367    2.9739   -6.0284
   -1.3656    2.9109   -5.9925
   -1.2944    2.8478   -5.9567
   -1.2232    2.7848   -5.9210
   -1.1519    2.7217   -5.8852
   -1.0807    2.6586   -5.8496
   -1.0094    2.5955   -5.8140
   -0.9381    2.5324   -5.7784
   -0.8668    2.4692   -5.7429
   -0.7955    2.4060   -5.7074
   -0.7242    2.3428   -5.6720
   -0.6528    2.2796   -5.6366
   -0.5814    2.2163   -5.6013
   -0.5100    2.1530   -5.5661
   -0.4385    2.0897   -5.5309
   -0.3670    2.0264   -5.4957
   -0.2955    1.9630   -5.4607
   -0.2240    1.8996   -5.4256
   -0.1524    1.8362   -5.3906
   -0.0808    1.7727   -5.3557
   -0.0092    1.7093   -5.3209
    0.0625    1.6458   -5.2860
    0.1341    1.5822   -5.2513
    0.2059    1.5187   -5.2166
    0.2776    1.4551   -5.1819
    0.3494    1.3915   -5.1474
    0.4212    1.3279   -5.1128
    0.4931    1.2642   -5.0784
    0.5650    1.2005   -5.0440
    0.6369    1.1368   -5.0096
    0.7089    1.0730   -4.9753
    0.7809    1.0092   -4.9411
    0.8530    0.9454   -4.9069
    0.9251    0.8816   -4.8728
    0.9972    0.8177   -4.8388
    1.0694    0.7538   -4.8048
    1.1416    0.6899   -4.7709
    1.2139    0.6260   -4.7370
    1.2862    0.5620   -4.7032
    1.3585    0.4980   -4.6695
    1.4309    0.4339   -4.6358
    1.5034    0.3698   -4.6022
    1.5759    0.3057   -4.5686
    1.6484    0.2416   -4.5352
    1.7210    0.1774   -4.5017
    1.7936    0.1132   -4.4684
    1.8663    0.0490   -4.4351
    1.9391   -0.0153   -4.4019
    2.0119   -0.0796   -4.3687
    2.0847   -0.1439   -4.3356
    2.1576   -0.2083   -4.3026
    2.2306   -0.2726   -4.2697
    2.3036   -0.3371   -4.2368
    2.3767   -0.4015   -4.2040
    2.4498   -0.4660   -4.1712
    2.5230   -0.5305   -4.1385
    2.5962   -0.5951   -4.1059
    2.6695   -0.6597   -4.0734
    2.7429   -0.7243   -4.0409
    2.8163   -0.7890   -4.0085
    2.8898   -0.8537   -3.9762
    2.9634   -0.9184   -3.9439
    3.0370   -0.9831   -3.9117
    3.1106   -1.0479   -3.8796
    3.1844   -1.1128   -3.8476
    3.2582   -1.1776   -3.8156
    3.3320   -1.2425   -3.7837
    3.4060   -1.3075   -3.7519
    3.4800   -1.3724   -3.7201
    3.5541   -1.4374   -3.6884
    3.6282   -1.5025   -3.6568
    3.7024   -1.5675   -3.6253
    3.7767   -1.6327   -3.5939
    3.8510   -1.6978   -3.5625
    3.9255   -1.7630   -3.5312
    4.0000   -1.8282   -3.4999
    4.0745   -1.8935   -3.4688
    4.1492   -1.9588   -3.4377
    4.2239   -2.0241   -3.4067
    4.2987   -2.0895   -3.3758
    4.3736   -2.1549   -3.3450
    4.4485   -2.2203   -3.3142
    4.5236   -2.2858   -3.2835
    4.5987   -2.3513   -3.2529
    4.6739   -2.4169   -3.2224
    4.7491   -2.4825   -3.1920
    4.8245   -2.5481   -3.1616
    4.8999   -2.6138   -3.1313
    4.9755   -2.6795   -3.1011
    5.0511   -2.7453   -3.0710
    5.1267   -2.8111   -3.0409
    5.2025   -2.8769   -3.0110
    5.2784   -2.9428   -2.9811
    5.3543   -3.0087   -2.9513
    5.4303   -3.0747   -2.9216
    5.5065   -3.1407   -2.8920
    5.5827   -3.2067   -2.8624
    5.6590   -3.2728   -2.8330
    5.7354   -3.3389   -2.8036
    5.8118   -3.4051   -2.7743
    5.8884   -3.4713   -2.7451
    5.9651   -3.5375   -2.7160
    6.0418   -3.6038   -2.6870
    6.1187   -3.6701   -2.6580
    6.1957   -3.7365   -2.6292
    6.2727   -3.8029   -2.6004
    6.3498   -3.8693   -2.5717
    6.4271   -3.9358   -2.5431
    6.5044   -4.0024   -2.5146
    6.5819   -4.0690   -2.4862
    6.6594   -4.1356   -2.4579
    6.7370   -4.2023   -2.4296
    6.8148   -4.2690   -2.4015
    6.8926   -4.3357   -2.3734
    6.9706   -4.4025   -2.3455
    7.0486   -4.4694   -2.3176
    7.1268   -4.5362   -2.2898
    7.2050   -4.6032   -2.2621
    7.2834   -4.6702   -2.2345
    7.3619   -4.7372   -2.2070
    7.4405   -4.8042   -2.1796
    7.5191   -4.8713   -2.1523
    7.5979   -4.9385   -2.1250
    7.6769   -5.0057   -2.0979
    7.7559   -5.0730   -2.0709
    7.8350   -5.1402   -2.0439
    7.9142   -5.2076   -2.0171
    7.9936   -5.2750   -1.9903
    8.0731   -5.3424   -1.9637
    8.1526   -5.4099   -1.9371
    8.2323   -5.4774   -1.9106
    8.3122   -5.5450   -1.8842
    8.3921   -5.6126   -1.8580
    8.4721   -5.6803   -1.8318
    8.5523   -5.7480   -1.8057
    8.6326   -5.8157   -1.7797
    8.7130   -5.8835   -1.7539
    8.7935   -5.9514   -1.7281
    8.8742   -6.0193   -1.7024
    8.9549   -6.0873   -1.6768
    9.0358   -6.1553   -1.6513
    9.1169   -6.2233   -1.6260
    9.1980   -6.2914   -1.6007
    9.2793   -6.3596   -1.5755
    9.3607   -6.4278   -1.5504
    9.4422   -6.4960   -1.5254
    9.5238   -6.5643   -1.5006
    9.6056   -6.6327   -1.4758
    9.6875   -6.7011   -1.4511
    9.7695   -6.7695   -1.4266
    9.8517   -6.8380   -1.4021
    9.9340   -6.9066   -1.3778
   10.0164   -6.9752   -1.3535
   10.0990   -7.0438   -1.3294
   10.1817   -7.1125   -1.3053
   10.2645   -7.1813   -1.2814
   10.3475   -7.2501   -1.2576
   10.4306   -7.3189   -1.2338
   10.5138   -7.3878   -1.2102
   10.5972   -7.4568   -1.1867
   10.6807   -7.5258   -1.1633
   10.7644   -7.5949   -1.1400
   10.8482   -7.6640   -1.1168
   10.9321   -7.7332   -1.0938
   11.0162   -7.8024   -1.0708
   11.1004   -7.8717   -1.0479
   11.1848   -7.9410   -1.0252
   11.2693   -8.0104   -1.0026
   11.3539   -8.0798   -0.9800
   11.4387   -8.1493   -0.9576
   11.5237   -8.2188   -0.9353
   11.6087   -8.2884   -0.9131
   11.6940   -8.3581   -0.8910
   11.7794   -8.4278   -0.8691
   11.8649   -8.4976   -0.8472
   11.9506   -8.5674   -0.8255
   12.0364   -8.6373   -0.8038
   12.1224   -8.7072   -0.7823
   12.2085   -8.7772   -0.7609
   12.2948   -8.8472   -0.7396
   12.3813   -8.9173   -0.7185
   12.4679   -8.9875   -0.6974
   12.5546   -9.0577   -0.6765
   12.6415   -9.1279   -0.6557
   12.7286   -9.1983   -0.6350
   12.8158   -9.2686   -0.6144
   12.9032   -9.3391   -0.5939
   12.9907   -9.4096   -0.5735
   13.0784   -9.4801   -0.5533
   13.1663   -9.5507   -0.5332
   13.2543   -9.6214   -0.5132
   13.3425   -9.6921   -0.4933
   13.4309   -9.7629   -0.4735
   13.5194   -9.8337   -0.4539
   13.6080   -9.9046   -0.4344
   13.6969   -9.9756   -0.4150
   13.7859  -10.0466   -0.3957
   13.8751  -10.1177   -0.3765
   13.9644  -10.1888   -0.3575
   14.0539  -10.2600   -0.3386
   14.1436  -10.3313   -0.3198
   14.2334  -10.4026   -0.3011
   14.3235  -10.4740   -0.2826
   14.4137  -10.5454   -0.2641
   14.5040  -10.6169   -0.2458
   14.5946  -10.6884   -0.2277
   14.6853  -10.7600   -0.2096
   14.7761  -10.8317   -0.1917
   14.8672  -10.9035   -0.1739
   14.9584  -10.9753   -0.1562
   15.0499  -11.0471   -0.1387
   15.1414  -11.1190   -0.1213
   15.2332  -11.1910   -0.1040
   15.3252  -11.2631   -0.0868
   15.4173  -11.3352   -0.0697
   15.5096  -11.4073   -0.0528
   15.6021  -11.4796   -0.0360
   15.6948  -11.5519   -0.0194
   15.7876  -11.6242   -0.0029
   15.8806  -11.6966    0.0135
   15.9739  -11.7691    0.0298
   16.0673  -11.8417    0.0459
   16.1609  -11.9143    0.0619
   16.2547  -11.9869    0.0778
   16.3486  -12.0597    0.0936
   16.4428  -12.1325    0.1092
   16.5371  -12.2053    0.1247
   16.6317  -12.2783    0.1400
   16.7264  -12.3513    0.1552
   16.8213  -12.4243    0.1703
   16.9164  -12.4974    0.1853
   17.0117  -12.5706    0.2001
   17.1072  -12.6439    0.2148
   17.2029  -12.7172    0.2293
   17.2988  -12.7906    0.2437
   17.3949  -12.8640    0.2580
   17.4911  -12.9376    0.2721
   17.5876  -13.0111    0.2861
   17.6843  -13.0848    0.3000

Answer 1

Ahsan,

I think parfor might be what you're looking for. It requires the Parallel Computing Toolbox (PCT) to use. It works like this:

parfor i = 1:length(P)
    Object1.position = P(i,:);
end

Also, I would recommend using indexed structure fields, as I've done in the example below, as it increases the flexibility of any code that you write. Let me know if this doesn't work for you, and we'll try something else. I know another technique, but it's much messier. Good luck!

parfor i = 1:length(P)
    Object(i).position = P(i,:);
end

Edit: Ok, this may not work because parfor is pretty particular. But it the general concept should apply to the problem you're trying to solve. I can't be more specific without knowing more about your specific problem. The key point is, inside a parfor, you must iterate something (Object, below) by the parfors iterator (i, below) and assign that thing a value. I'm not sure if you can use a for-loop inside a parfor, so the first example below may break. The point is, this is how you do parallel processing in MATLAB. Try this:

parfor i = 1:4
    Object(i).position = P(i,:);
end

Edit 2:

parfor i = length(P) Object1 = struct(); Object1.position = P(i, :); end

Edit 3: Ok, one last thing. You can't use "sliced" structs (structs with fields) as input or output from a parfor so you have to do this:

parfor i = 1:length(P)
    positionArray1(i) = P(i, :);
end
Object1 = struct('position', positionArray1);