Elementary matrices.
zeros- Zeros array.
ones- Ones array.
eye- Identity matrix.
repmat- Replicate and tile array.
rand- Uniformly distributed random numbers.
randn- Normally distributed random numbers.
linspace- Linearly spaced vector.
logspace- Logarithmically spaced vector.
freqspace- Frequency spacing for frequency response.
meshgrid- X and Y arrays for 3-D plots.
accumarray- Construct an array with accumulation.
:- Regularly spaced vector and index into matrix.
Basic array information.
size- Size of array.
length- Length of vector.
ndims- Number of dimensions.
numel- Number of elements.
disp- Display matrix or text.
isempty- True for empty array.
isequal- True if arrays are numerically equal.
isequalwithequalnans - True if arrays are numerically equal.
Matrix manipulation.
cat- Concatenate arrays.
reshape- Change size.
diag- Diagonal matrices and diagonals of matrix.
blkdiag- Block diagonal concatenation.
tril- Extract lower triangular part.
triu- Extract upper triangular part.
fliplr- Flip matrix in left/right direction.
flipud- Flip matrix in up/down direction.
flipdim- Flip matrix along specified dimension.
rot90- Rotate matrix 90 degrees.
:- Regularly spaced vector and index into matrix.
find- Find indices of nonzero elements.
end- Last index.
sub2ind- Linear index from multiple subscripts.
ind2sub- Multiple subscripts from linear index.
Array utility functions.
isscalar- True for scalar.
isvector- True for vector.
Special variables and constants.
ans- Most recent answer.
eps- Floating point relative accuracy.
realmax- Largest positive floating point number.
realmin- Smallest positive floating point number.
pi- 3.1415926535897....
i, j- Imaginary unit.
inf- Infinity.
NaN- Not-a-Number.
isnan- True for Not-a-Number.
isinf- True for infinite elements.
isfinite- True for finite elements.
why- Succinct answer.