Standard deviation of 2D array

Hi,

I am trying to calculate the standard deviation of 2D array 'v' of dimesnion 89 x 97.

I have tried as follows ,but it returns the output in the form of 1 x 97 instread of 89 x 97. Could someone help me with this

V1 = std (v);

Answer 1

[Star Strider]

The standard deviation of a scalar is 0 so the result is —

standard_deviation_v = zeros(size(v))

in this instance.

.

[Turbulence Analysis]

Hi,

Thanks I just checked. Though it yields results in 89 x 97 array, however, all the standard deviation values are zero..

[Star Strider]

As they should be.

The standard deviations are valid and non-zero if taken across rows or columns (on in a multidmiensional array, a specific dimension).

Calculating the standard deivation across the third dimension here (so each individual scalar) produces —

v = rand(89,97)

v = 89×97

0.3176 0.4743 0.4498 0.2482 0.4525 0.6837 0.4908 0.2914 0.9379 0.1937 0.6850 0.5043 0.2961 0.2275 0.7154 0.2022 0.0023 0.9774 0.0146 0.9340 0.9574 0.3732 0.7484 0.0872 0.1360 0.5074 0.5602 0.8739 0.0030 0.5378 0.2584 0.1894 0.3723 0.9644 0.0514 0.3840 0.5639 0.4938 0.4834 0.4695 0.6003 0.3930 0.9223 0.2461 0.2159 0.4884 0.8516 0.6950 0.9837 0.4972 0.1860 0.1820 0.2270 0.2164 0.3897 0.0965 0.4047 0.9546 0.3066 0.9510 0.0362 0.5856 0.0955 0.1356 0.7095 0.5816 0.1061 0.9346 0.1909 0.4830 0.9627 0.5205 0.6587 0.7511 0.4202 0.0762 0.2718 0.0027 0.5365 0.9341 0.5114 0.1364 0.6142 0.8989 0.0643 0.5395 0.2587 0.3957 0.8722 0.8927 0.5580 0.9194 0.7983 0.8412 0.5769 0.8895 0.3469 0.0505 0.1800 0.6799 0.4938 0.5923 0.2852 0.6942 0.6023 0.3313 0.9509 0.0939 0.5642 0.8119 0.9132 0.2708 0.7792 0.8428 0.6634 0.7914 0.1808 0.4120 0.7127 0.8783 0.5743 0.9389 0.4356 0.2958 0.1456 0.0101 0.0334 0.3761 0.0551 0.5322 0.4195 0.3785 0.6602 0.7843 0.1021 0.5288 0.5701 0.9108 0.1013 0.9304 0.1100 0.1890 0.4810 0.9255 0.3429 0.0091 0.4485 0.1633 0.5688 0.0930 0.4730 0.7792 0.0324 0.9049 0.0409 0.9804 0.1001 0.6882 0.8350 0.0176 0.9968 0.2064 0.1408 0.8134 0.8692 0.8671 0.8323 0.2955 0.8186 0.3277 0.0561 0.5148 0.4377 0.1855 0.2647 0.1639 0.6836 0.6931 0.5509 0.3950 0.6487 0.9884 0.9817 0.3008 0.0589 0.3406 0.1499 0.7129 0.7021 0.3067 0.5540 0.4717 0.2021 0.3025 0.2733 0.4091 0.8190 0.3141 0.4931 0.2977 0.8817 0.4532 0.0145 0.5354 0.9743 0.0855 0.2653 0.3339 0.8514 0.1727 0.8610 0.7541 0.0731 0.5767 0.3492 0.6835 0.5188 0.1462 0.9584 0.1433 0.8594 0.1973 0.6940 0.7562 0.7208 0.4494 0.9059 0.5781 0.0174 0.8602 0.1506 0.9939 0.0943 0.9477 0.7425 0.5248 0.5851 0.8669 0.0807 0.4423 0.4303 0.6783 0.5461 0.7124 0.7804 0.7018 0.6898 0.6771 0.7743 0.1767 0.4670 0.4155 0.8837 0.0245 0.7318 0.0056 0.4344 0.6394 0.6097 0.7438 0.0043 0.3886 0.8524 0.8176 0.8685 0.8124 0.8072 0.6733 0.3688 0.1457 0.6304 0.3754 0.7873 0.5024 0.5350 0.9765 0.5470 0.0514 0.9915 0.1818 0.8456 0.2711 0.0711 0.3204 0.8498 0.2127 0.4112 0.8229 0.8036 0.5223 0.8232 0.9784 0.7524 0.1801 0.7947 0.7446 0.5634 0.7837 0.1725 0.1128

standard_deviation_v = std(v,[],3)

standard_deviation_v = 89×97

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

This is of course the expected result.

.

[Turbulence Analysis]

Ok, I will look into this..

[Star Strider]

Thank you.

.