ответвлено от main/it-labs
462 строки
9.7 KiB
Markdown
462 строки
9.7 KiB
Markdown
### пункт 5
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help randn
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```
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'randn' is a built-in function from the file libinterp/corefcn/rand.cc
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```
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```matlab
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-- X = randn (N)
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-- X = randn (M, N, ...)
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-- X = randn ([M N ...])
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-- X = randn (..., "single")
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-- X = randn (..., "double")
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-- V = randn ("state")
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-- randn ("state", V)
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-- randn ("state", "reset")
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-- V = randn ("seed")
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-- randn ("seed", V)
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-- randn ("seed", "reset")
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Return a matrix with normally distributed random elements having
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zero mean and variance one.
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```
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```
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The arguments are handled the same as the arguments for 'rand'.
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```
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### пункт 6
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*матрица А со случайными, нормально распределенными элементами, с 4 строками и 6 столбцам:*
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```matlab
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>> A=randn(4,6)
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A =
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-1.566040 1.022528 -1.082336 1.060574 -1.166946 -0.040025
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0.729186 -0.929840 -1.381007 1.147912 0.360731 -1.612832
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-0.481197 -0.439834 1.347738 -0.398764 -0.024576 0.636071
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-0.607566 0.069257 0.057204 -1.166324 -1.470205 -1.034399
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```
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*матрица В 4х7 со случайными элементами, равномерно распределенными в диапазоне от 0 до 1:*
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```matlab
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>> B=rand(4,7)
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B =
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0.344256 0.014810 0.424571 0.078178 0.264139 0.781169 0.804127
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0.992425 0.465993 0.834274 0.087590 0.053326 0.580783 0.025481
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0.196239 0.896082 0.504587 0.599906 0.332032 0.145209 0.696585
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0.581111 0.135927 0.371084 0.824356 0.089142 0.096275 0.830373
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```
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*вектор С с целыми числами от 4 до 27:*
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```matlab
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>> C = 4:27
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C =
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Columns 1 through 23:
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4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26
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Column 24:
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27
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```
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*символьный вектор Н:*
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```matlab
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>> H='This is a symbols vector'
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H = This is a symbols vector
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```
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*вектор-строка L с 2 комплексными элементами:*
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```matlab
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>> L=[-2+23.1j, 3-5.6j]
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L =
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-2.0000 + 23.1000i 3.0000 - 5.6000i
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```
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### пункт 7
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*преобразование матрицы С в матрицу с 6 столбцами:*
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```matlab
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D=reshape(C,[],6)
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D =
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4 8 12 16 20 24
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5 9 13 17 21 25
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6 10 14 18 22 26
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7 11 15 19 23 27
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```
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*матричное перемножение В и А с транспонированием матрицы В:*
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```matlab
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E=B'*A
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E =
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-0.262949 -0.616852 -1.445425 0.748308 -0.902905 -2.090672
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-0.197173 -0.802869 0.555891 0.034765 -0.071047 -0.322792
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-0.524818 -0.537841 -0.910387 0.773946 -0.752473 -1.425434
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-0.848085 -0.208271 0.650095 -1.017228 -1.286349 -0.615527
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-0.588700 0.080639 0.093061 0.104981 -0.428217 0.022409
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-0.928210 0.201532 -1.446341 1.324983 -0.847188 -0.975195
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-2.080416 0.549677 0.080791 -0.364171 -2.167119 -0.489140
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```
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*создание матрицы путем «горизонтального» соединения матриц А и В:*
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```matlab
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F=[A,B]
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F =
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Columns 1 through 10:
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-1.566040 1.022528 -1.082336 1.060574 -1.166946 -0.040025 0.344256 0.014810 0.424571 0.078178
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0.729186 -0.929840 -1.381007 1.147912 0.360731 -1.612832 0.992425 0.465993 0.834274 0.087590
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-0.481197 -0.439834 1.347738 -0.398764 -0.024576 0.636071 0.196239 0.896082 0.504587 0.599906
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-0.607566 0.069257 0.057204 -1.166324 -1.470205 -1.034399 0.581111 0.135927 0.371084 0.824356
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Columns 11 through 13:
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0.264139 0.781169 0.804127
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0.053326 0.580783 0.025481
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0.332032 0.145209 0.696585
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0.089142 0.096275 0.830373
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```
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*поэлементное перемножение матриц A и D:*
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```matlab
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G=A.*D
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G =
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-6.2642 8.1802 -12.9880 16.9692 -23.3389 -0.9606
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3.6459 -8.3686 -17.9531 19.5145 7.5754 -40.3208
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-2.8872 -4.3983 18.8683 -7.1778 -0.5407 16.5379
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-4.2530 0.7618 0.8581 -22.1602 -33.8147 -27.9288
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```
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*поэлементное деление элементов матрицы G на 4.5:*
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```matlab
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M = G./4.5
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M =
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-1.3920 1.8178 -2.8862 3.7709 -5.1864 -0.2135
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0.8102 -1.8597 -3.9896 4.3366 1.6834 -8.9602
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-0.6416 -0.9774 4.1930 -1.5951 -0.1202 3.6751
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-0.9451 0.1693 0.1907 -4.9245 -7.5144 -6.2064
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```
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*поэлементное возведение в степень элементов матрицы D:*
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```matlab
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DDD=D.^3
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DDD =
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64 512 1728 4096 8000 13824
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125 729 2197 4913 9261 15625
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216 1000 2744 5832 10648 17576
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343 1331 3375 6859 12167 19683
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```
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*создание логической матрицы, совпадающей по размерам с D и с элементами по заданному условию:*
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```matlab
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DL=D>=20
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DL =
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0 0 0 0 1 1
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0 0 0 0 1 1
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0 0 0 0 1 1
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0 0 0 0 1 1
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```
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*превращение матрицы в вектор-столбец:*
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```matlab
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Dstolb=D(:)
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Dstolb =
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4
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5
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6
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7
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8
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9
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10
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11
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12
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13
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14
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15
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16
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17
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18
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19
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20
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21
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22
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23
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24
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25
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26
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27
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```
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### пункт 8
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*математические функции:*
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```matlab
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B1=sqrt(B)
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B1 =
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0.5867 0.1217 0.6516 0.2796 0.5139 0.8838 0.8967
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0.9962 0.6826 0.9134 0.2960 0.2309 0.7621 0.1596
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0.4430 0.9466 0.7103 0.7745 0.5762 0.3811 0.8346
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0.7623 0.3687 0.6092 0.9079 0.2986 0.3103 0.9112
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```
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```matlab
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>> B2=log(B)
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B2 =
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-1.0664e+00 -4.2125e+00 -8.5668e-01 -2.5488e+00 -1.3313e+00 -2.4696e-01 -2.1800e-01
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-7.6041e-03 -7.6358e-01 -1.8119e-01 -2.4351e+00 -2.9313e+00 -5.4338e-01 -3.6698e+00
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-1.6284e+00 -1.0972e-01 -6.8401e-01 -5.1098e-01 -1.1025e+00 -1.9296e+00 -3.6156e-01
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-5.4281e-01 -1.9956e+00 -9.9133e-01 -1.9315e-01 -2.4175e+00 -2.3405e+00 -1.8588e-01
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```
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```matlab
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>> B3=sin(B)
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B3 =
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0.337496 0.014809 0.411930 0.078099 0.261078 0.704110 0.720225
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0.837354 0.449310 0.740809 0.087478 0.053301 0.548679 0.025478
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0.194982 0.780886 0.483446 0.564565 0.325965 0.144699 0.641602
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0.548953 0.135509 0.362626 0.734111 0.089024 0.096126 0.738183
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```
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*операции с матрицами:*
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```matlab
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k=length(B1)
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k = 7
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```
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```matlab
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>> nm=size(B1)
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nm =
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4 7
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```
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```matlab
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>> elem=numel(B1)
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elem = 28
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```
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```matlab
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>> NN=linspace(11.5,34.1,20)
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NN =
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Columns 1 through 13:
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11.500 12.689 13.879 15.068 16.258 17.447 18.637 19.826 21.016 22.205 23.395 24.584 25.774
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Columns 14 through 20:
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26.963 28.153 29.342 30.532 31.721 32.911 34.100
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```
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```matlab
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>> FF=ones(2,4)
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FF =
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1 1 1 1
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1 1 1 1
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```
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```matlab
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GG=zeros(5)
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GG =
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0 0 0 0 0
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0 0 0 0 0
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0 0 0 0 0
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0 0 0 0 0
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0 0 0 0 0
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```
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```matlab
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>> B1D=diag(B1)
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B1D =
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0.5867
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0.6826
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0.7103
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0.9079
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```
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```matlab
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>> DB=diag(B1D)
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DB =
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Diagonal Matrix
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0.5867 0 0 0
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0 0.6826 0 0
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0 0 0.7103 0
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0 0 0 0.9079
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```
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```matlab
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>> BS1=sort(B)
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BS1 =
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0.196239 0.014810 0.371084 0.078178 0.053326 0.096275 0.025481
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0.344256 0.135927 0.424571 0.087590 0.089142 0.145209 0.696585
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0.581111 0.465993 0.504587 0.599906 0.264139 0.580783 0.804127
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0.992425 0.896082 0.834274 0.824356 0.332032 0.781169 0.830373
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```
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```matlab
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>> BS2=sortrows(B,2)
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BS2 =
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0.344256 0.014810 0.424571 0.078178 0.264139 0.781169 0.804127
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0.581111 0.135927 0.371084 0.824356 0.089142 0.096275 0.830373
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0.992425 0.465993 0.834274 0.087590 0.053326 0.580783 0.025481
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0.196239 0.896082 0.504587 0.599906 0.332032 0.145209 0.696585
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```
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```matlab
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>> DS1=sum(D)
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DS1 =
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22 38 54 70 86 102
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```
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```matlab
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DS2=sum(D,2)
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DS2 =
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84
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90
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96
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102
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```
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```matlab
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>> DP1=prod(D)
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DP1 =
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840 7920 32760 93024 212520 421200
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```
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```matlab
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>> dt=det(A*A')
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dt = 246.59
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```
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```matlab
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>> dinv=inv(A*A')
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dinv =
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0.192611 0.079161 0.204485 -0.052344
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0.079161 0.325357 0.425809 0.012347
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0.204485 0.425809 0.973266 -0.029157
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-0.052344 0.012347 -0.029157 0.219869
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```
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### пункт 9
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```matlab
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D1=D(3,5)
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D1 = 22
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```
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```matlab
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>> D2=D(3,4:end)
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D2 =
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18 22 26
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```
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```matlab
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>> D3=D(2:3,3:5)
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D3 =
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13 17 21
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14 18 22
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```
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```matlab
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>> D4=D(16:20)
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D4 =
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19 20 21 22 23
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```
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```matlab
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>> D5=D(3:4,[1,3,6])
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D5 =
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6 14 26
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7 15 27
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```
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### пункт 10
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*цикл по перечислению:*
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```matlab
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Dsum=0
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Dsum = 0
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>> for i=1:6
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Dsum=Dsum+sqrt(D(2,i))
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endfor
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Dsum = 2.2361
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Dsum = 5.2361
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Dsum = 8.8416
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Dsum = 12.965
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Dsum = 17.547
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Dsum = 22.547
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```
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*цикл пока выполняется условие:*
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```matlab
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Dsum2=0;i=1
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i = 1
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>> while (D(i)<22)
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Dsum2=Dsum2+sin(D(i))
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i=i+1
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endwhile
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Dsum2 = -0.7568
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i = 2
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Dsum2 = -1.7157
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i = 3
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Dsum2 = -1.9951
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i = 4
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Dsum2 = -1.3382
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i = 5
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Dsum2 = -0.3488
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i = 6
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Dsum2 = 0.063321
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i = 7
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Dsum2 = -0.4807
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i = 8
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Dsum2 = -1.4807
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i = 9
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Dsum2 = -2.0173
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i = 10
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Dsum2 = -1.5971
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i = 11
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Dsum2 = -0.6065
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i = 12
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Dsum2 = 0.043799
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i = 13
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Dsum2 = -0.2441
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i = 14
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Dsum2 = -1.2055
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i = 15
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Dsum2 = -1.9565
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i = 16
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Dsum2 = -1.8066
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i = 17
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Dsum2 = -0.8937
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i = 18
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Dsum2 = -0.057011
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i = 19
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```
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*условие if:*
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```matlab
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if (D(3,5)>=20)
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printf('D(3,5)>=20')
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else
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printf('D(3,5)<20')
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endif
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D(3,5)>=20
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```
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### пункт 12
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*Программа Progl*
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```matlab
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D1 = 22
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D2 =
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18 22 26
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D3 =
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13 17 21
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14 18 22;
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D4 =
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19 20 21 22 23
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D5 =
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6 14 26
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7 15 27;
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``` |