MATLAB: Let say that I want to generate random numbers between 1-6 for output 5×6..each row will generate random number between 1-6..tq

let say that i want to generate random numbers between 1-6 for output 5x6..each row will generate random number between 1-6..tq

Let say that I want to generate random numbers between 1-6 for output 5×6..each row will generate random number between 1-6..tq

Best Answer

You can use randi to generate uniformly distributed integer values:

>> randi(6, [5,6])
ans =
   5     6     6     3     3     2
   2     4     2     2     5     5
   4     1     5     2     4     5
   5     1     2     4     4     3
   6     2     6     3     6     4
>> randi(6, [5,6])
ans =
   1     1     1     4     3     5
   1     4     5     2     1     4
   4     3     2     4     2     6
   5     1     4     5     6     1
   6     3     1     5     1     3

If you want uniformly distributed decimal values, then use rand:

>> 1+5*rand([5,6])
ans =
     1.5333       5.3435       3.1571       1.6803       5.2652       1.3798
     5.8095       1.4222       5.5532       5.3465       4.1103       2.1996
     1.0232       2.9989       1.9092       3.8985       2.7548       1.6166
     4.8746       2.2994        2.319       3.7493       3.5662       1.9195
     5.0865       5.0003       1.7277       1.7248        3.009       2.1998
>> 1+5*rand([5,6])
ans =
     3.0863       3.4463       4.9013       1.6599       2.1739        1.845
     1.2483       2.6886       2.9487       5.7103       2.7658       4.2456
     5.5136       5.5003       2.2085       5.7807        5.106       4.6586
     5.7239       2.8462       3.0196        3.876        1.077       4.2387
     3.4543        1.556       1.4823       1.2989       1.2151       3.2546

And of course remember that no computer-based "random" number is truly random.

Related Solutions

MATLAB: ERROR Dimensions of arrays being concatenated are not consistent.

X = [2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23];
Y = [23,22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2];
V = [6.630, 7.650, 8.030, 8.170, 8.370, 8.400, 8.400, 8.370, 8.360, 8.390, 8.280, 8.270, 8.280, 8.290, 8.220, 8.250, 8.160, 8.080, 7.710, 7.370, 7.320, 4.110, 5.050, 6.330, 7.020, 7.350, 7.600, 7.700, 7.740, 7.770, 7.750, 7.750, 7.710, 7.630, 7.560, 7.550, 7.400, 7.300, 7.190, 6.920, 6.420, 5.850, 5.720, 2.920, 4.350, 5.520, 6.230, 6.710, 6.920, 7.100, 7.160, 7.190, 7.180, 7.130, 7.050, 7.050, 6.970, 6.850, 6.660, 6.500, 6.320, 6.010, 5.320, 4.730, 4.570, 2.339, 3.940, 5.000, 5.620, 6.090, 6.280, 6.440, 6.570, 6.590, 6.610, 6.600, 6.500, 6.470, 6.340, 6.220, 5.920, 5.790, 5.550, 5.220, 4.670, 3.980, 3.840, 2.002, 3.725, 4.620, 5.170, 5.550, 5.770, 5.970, 6.100, 6.110, 6.120, 6.070, 6.020, 5.920, 5.800, 5.610, 4.420, 5.190, 4.950, 4.590, 4.070, 3.440, 3.392, 1.860, 3.549, 4.330, 4.790, 5.170, 5.350, 5.580, 5.620, 5.650, 5.660, 5.580, 5.520, 5.450, 5.310, 5.150, 4.800, 4.640, 4.390, 4.060, 3.580, 3.043, 3.035, 1.730, 3.404, 4.110, 4.520, 4.840, 5.010, 5.160, 5.210, 5.220, 5.220, 5.170, 5.110, 4.990, 4.870, 4.670, 4.350, 4.210, 3.960, 3.649, 3.215, 2.718, 2.711, 1.658, 3.301, 3.920, 4.300, 4.550, 4.700, 4.820, 4.840, 4.830, 4.810, 4.740, 4.650, 4.600, 4.450, 4.240, 4.030, 3.830, 3.571, 3.288, 2.900, 2.488, 2.460, 1.554, 3.212, 3.753, 4.110, 4.310, 4.420, 4.500, 4.500, 4.510, 4.450, 4.380, 4.310, 4.210, 4.070, 3.870, 3.627, 3.470, 3.259, 2.937, 2.636, 2.291, 2.243, 1.468, 3.137, 3.615, 3.920, 4.070, 4.130, 4.220, 4.230, 4.190, 4.130, 4.040, 3.980, 3.850, 3.740, 3.540, 3.338, 3.194, 3.010, 2.713, 2.414, 2.115, 2.087, 1.397, 3.069, 3.500, 3.764, 3.900, 3.920, 3.960, 3.940, 3.870, 3.830, 3.787, 3.660, 3.560, 3.427, 3.245, 3.035, 2.903, 2.717, 2.468, 2.222, 1.953, 1.948, 1.323, 2.984, 3.351, 3.616, 3.715, 3.711, 3.717, 3.670, 3.600, 3.540, 3.469, 3.350, 3.266, 3.139, 2.945, 2.760, 2.611, 2.475, 2.248, 2.009, 1.782, 1.758, 1.238, 2.892, 3.224, 3.450, 3.554, 3.465, 3.500, 3.451, 3.369, 3.313, 3.176, 3.097, 2.990, 2.894, 2.712, 2.524, 2.403, 2.240, 2.052, 1.847, 1.626, 1.610, 1.143, 2.779, 3.118, 3.313, 3.367, 3.289, 3.300, 3.193, 3.122, 3.056, 2.936, 2.835, 2.734, 2.622, 2.456, 2.288, 2.155, 2.057, 1.900, 1.679, 1.484, 1.483, 1.042, 2.689, 3.070, 3.161, 3.204, 3.100, 3.079, 2.982, 2.880, 2.800, 2.686, 2.600, 2.499, 2.383, 2.222, 2.070, 2.090, 1.839, 1.691, 1.513, 1.337, 1.325, 0.941, 2.703, 2.952, 3.043, 3.022, 2.931, 2.835, 2.761, 2.646, 2.584, 2.445, 2.360, 2.271, 2.165, 2.027, 1.846, 1.779, 1.656, 1.510, 1.351, 1.210, 1.211, 0.824, 2.643, 2.854, 2.901, 2.830, 2.709, 2.624, 2.523, 2.404, 2.339, 2.213, 2.131, 2.042, 1.936, 1.050, 1.658, 1.593, 1.457, 1.332, 1.210, 1.064, 1.064, 0.715, 2.850, 2.748, 2.718, 2.625, 2.477, 2.389, 2.275, 2.169, 2.084, 1.982, 1.900, 1.810, 1.731, 1.602, 1.468, 1.417, 1.307, 1.170, 1.071, 0.947, 0.946, 0.642, 2.767, 2.590, 2.506, 2.394, 2.241, 2.122, 2.025, 1.927, 1.893, 1.751, 1.743, 1.601, 1.554, 1.408, 1.285, 1.249, 1.142, 1.024, 0.919, 0.815, 0.830, 0.538, 2.651, 2.370, 2.212, 2.045, 1.930, 1.856, 1.741, 1.680, 1.840, 1.505, 1.470, 1.398, 1.320, 1.246, 1.097, 1.078, 0.992, 0.883, 0.787, 0.702, 0.702, 0.436, 2.381, 2.050, 1.791, 1.690, 1.601, 1.558, 1.497, 1.421, 1.360, 1.284, 1.231, 1.188, 1.107, 1.019, 0.924, 0.925, 0.852, 0.743, 0.668, 0.588, 0.601, 0.366, 1.947, 1.489, 1.298, 1.230, 1.211, 1.226, 1.199, 1.182, 1.220, 1.052, 1.008, 0.978, 0.930, 0.852, 0.735, 0.764, 0.706, 0.619, 0.560, 0.492, 0.474, 0.229];
V=reshape(V,numel(X),numel(Y));
contourf (X,Y,V)

MATLAB: “If function” can’t distinguish i ~= 1.6.

"This weird thing only happens when i=1.6."

Nothing weird happens: you generate binary floating point numbers using two different methods and get slightly different output values for some input values. That is in the nature of binary floating point numbers.

"Is it a bug..."

No.

"...or is there something wrong with my code."

Yes. You assumed that numeric mathematics is the same as symbolic or algebraic mathematics. But it isn't.

In your example you did not take into account the acccumulated floating point error, which means that you should never test for exact equality of binary floating point numbers, but should always compare the absolute difference againsts a tolerance: