Matlab diary from lecture 1, Math 445 08/27/2013
format compact 4+2 ans = 6 4*3 % multiplication is star (asterisk) ans = 12 3/4 ans = 0.7500 4\3 ans = 0.7500 % precedence 4+3*2 ans = 10 4+5; % semicolon supresses output x = 3 % assignment: assign 3 to the variable x x = 3 x = 4 + 5 x = 9 x = x + 1 % Note: as an equation, this is nonsense. But it's an assignment! x = 10 x == 10 % This is a boolean expression (Boole) ans = 1 % 1 means true x == 11 % this is a boolean expression ans = 0 % 0 means false x = 10 % examples of boolean expressions x > 7 ans = 1 % true x < 14 ans = 1 % true x <= 10 ans = 1 % true x >= 10 ans = 1 % true x >= 17 ans = 0 % false pi ans = 3.1416 % The Matlab "help" provides help on specific topic and functions, e.g. help format format long pi ans = 3.141592653589793 1/0 ans = Inf acos(2) ans = 0 + 1.316957896924817i NaN % is Not a Number ans = NaN % matlab's basic numerical type is a real (complex) number % plus a couple special numbers: Inf and NaN % Matlab has different "types" to represetn different type of numbers % The function "class" rerurns the type of a number class(pi) ans = double % "double" means "double precision floating-point number, 16 digits" pi ans = 3.141592653589793 class(1) ans = double int32(1) ans = 1 class(int32(1)) ans = int32 n = int32(1) n = 1 class(n) ans = int32 % int32 is a 32-bit integer n = int64(1) n = 1 class(n) ans = int64