Page 371 - Process Modelling and Simulation With Finite Element Methods

358 Process Modelling and Simulation with Finite Element Methods
>> a=[O: 0.1: 1l*pi
a=
Columns 1 through 8
0 0.3142 0.6283 0,9425 1.2566 1.5708 1.8850 2.1991
Columns 9 through 11
2.5133 2.8274 3 I 1416
which produces eleven values equally spaced between 0 and K. So does
a=linspace (O,pi,11)
a=
Columns 1 through 8
0 0.3142 0.6283 0.9425 1.2566 1.5708 1.8850 2.1991
columns 9 through 11
2.5133 2.8274 3.1416
1 inspace is a versatile command for automatic matrix generation, performing
a role that is often done in looping constructs in older programming languages.
>> help linspace
LINSPACE Linearly spaced vector.
LINSPACE(X1, X2) generates a row vector of 100 linearly
equally spaced points between X1 and X2.
LINSPACE(X1, X2, N) generates N points between X1 and X2.
For N < 2, LINSPACE returns X2.
See also LOGSPACE, :.
logspace comes in handy as well.
>> help logspace
LOGSPACE Logarithmically spaced vector.
LOGSPACE(X1, X2) generates a row vector of 50 logarithmically
equally spaced points between decades 1O*X1 and 10AX2. If X2
is pi, then the points are between 10AX1 and pi.
LOGSPACE(X1, X2, N) generates N points.
For N < 2, LOGSPACE returns lO"X2.
See also LINSPACE, :.
Four other common array generators are zeros, ones, rand, and for matrices,
eye. zeros initializes an array with zeros; ones with ones, rand with
uniformly distributed random numbers (randn with normal deviates) and eye
with the identity matrix.
>> help zeros
ZEROS Zeros array.
ZEROS(N) is an N-by-N matrix of zeros.
ZEROS(M,N) or ZEROS( [M,N] is an M-by-N matrix of zeros.
)
ZEROS (M,N,P, . . .) or ZEROS ( [M N P . . .I ) is an M-by-N-by-P-by-. .
array of zeros.
ZEROS(SIZE(A)) is the same size as A and all zeros.
>> help ones
ONES Ones array.
ONES(N) is an N-by-N matrix of ones.
ONES(M,N) or ONES([M,NI) is an M-by-N matrix of ones.
ONES(M,N,P, ... ) or ONES([M N P ... I) is an M-by-N-by-P-by-..
array of ones.
ONES(SIZE(A)) is the same size as A and all ones.