diff

Differences and approximate derivatives.

Syntax

• Y = diff(X)
• Y = diff(X, n)
• Y = diff(X, n, dim)

Input argument

• X - vector or matrix (real or single)
• n - difference order: positive integer scalar or []
• dim - dimension: positive integer scalar

Output argument

• Y - difference array: vector or matrix.

Description

If X is a vector of length n, result of diff(X) is a vector of first differences X(2) - X(1), ..., X(n) - X(n-1).

If X is a matrix, result of diff(X) is a matrix of column differences along the first non-singleton dimension.

Example

h = .01; x = 0:h:pi;
X = sin(x.^2);
R = diff(X)

See also

sum, prod.

History

Author

Allan CORNET